Carrier 48TC__16 User Manual

48TC**16  
Single Package Rooftop  
Gas Heating/Electric Cooling Unit  
with Puronr (R---410A) Refrigerant  
Size 16  
Installation Instructions  
NOTE: Read the entire instruction manual before starting  
the installation  
Units with Factory-Installed Disconnect . . . . . . . 15  
Convenience Outlets . . . . . . . . . . . . . . . . . . . . . . . 16  
Factory-Option Thru-Base Connections  
(Electrical Connections) . . . . . . . . . . . . . . . . . . . . 18  
TABLE OF CONTENTS  
SAFETY CONSIDERATIONS . . . . . . . . . . . . . . . . . . . . 2  
Units without Thru-Base Connections . . . . . . . . . 18  
Field Control Wiring . . . . . . . . . . . . . . . . . . . . . . . 18  
Thermostat . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18  
Unit without Thru-Base Connection Kit . . . . . . . 19  
Heat Anticipator Settings . . . . . . . . . . . . . . . . . . . 19  
Humidi-MiZerR Control Connections . . . . . . . . . . 20  
Humidi-MiZer - Space RH Controller . . . . . . . . 20  
PremierLinkt (Factory Option) . . . . . . . . . . . . . . . . . 21  
Supply Air Temperature (SAT) Sensor . . . . . . . . . 25  
Outdoor Air Temperature (OAT) Sensor . . . . . . . 25  
EconoMi$er2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25  
Field Connections . . . . . . . . . . . . . . . . . . . . . . . . . . 25  
Space Sensors . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27  
Connect Thermostat . . . . . . . . . . . . . . . . . . . . . . . 27  
Configure the Unit for Thermostat Mode . . . . . . 27  
Economizer Controls . . . . . . . . . . . . . . . . . . . . . . . . 28  
Indoor Air Quality (CO2 sensor) . . . . . . . . . . . . . 28  
Outdoor Air Quality Sensor . . . . . . . . . . . . . . . . . 28  
INSTALLATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4  
Jobsite Survey . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4  
Step 1 - Plan for Unit Location . . . . . . . . . . . . . . . . . . 4  
Roof Mount . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5  
Step 2 - Plan for Sequence of Unit Installation . . . . . . 5  
Curb-Mount Installation . . . . . . . . . . . . . . . . . . . . . 5  
Pad-Mount Installation . . . . . . . . . . . . . . . . . . . . . . 5  
Frame-Mount Installation . . . . . . . . . . . . . . . . . . . . 5  
Step 3 - Inspect Unit . . . . . . . . . . . . . . . . . . . . . . . . . . . 5  
Step 4 - Provide Unit Support . . . . . . . . . . . . . . . . . . . 5  
Roof Curb Mount . . . . . . . . . . . . . . . . . . . . . . . . . . 5  
Slab Mount (Horizontal Units Only) . . . . . . . . . . . 5  
Alternate Unit Support  
(In Lieu of Curb or Slab Mount) . . . . . . . . . . . . . . 5  
Step 5 - Field Fabricate Ductwork . . . . . . . . . . . . . . . . 7  
Step 6 - Rig and Place Unit . . . . . . . . . . . . . . . . . . . . . 7  
Positioning on Curb . . . . . . . . . . . . . . . . . . . . . . . . 8  
Step 7 - Convert to Horizontal and Connect Ductwork . . . 8  
Step 8 - Install Outside Air Hood . . . . . . . . . . . . . . . . 9  
Space Relative Humidity Sensor or  
Humidistat Connections . . . . . . . . . . . . . . . . . . . . 29  
Economizer Hood Removal and Setup —  
Factory Option . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9  
Smoke Detector/Fire Shutdown (FSD) . . . . . . . . . 30  
Filter Status Switch . . . . . . . . . . . . . . . . . . . . . . . . 30  
Supply Fan Status Switch . . . . . . . . . . . . . . . . . . . 30  
Remote Occupied Switch . . . . . . . . . . . . . . . . . . . 30  
Power Exhaust (output) . . . . . . . . . . . . . . . . . . . . . 30  
CCN Communication Bus . . . . . . . . . . . . . . . . . . 31  
RTU Open Control System . . . . . . . . . . . . . . . . . . . . . 32  
Supply Air Temperature (SAT) Sensor . . . . . . . . . 35  
Outdoor Air Temperature (OAT) Sensor . . . . . . . 35  
EconoMi$er2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35  
Field Connections . . . . . . . . . . . . . . . . . . . . . . . . . . 35  
Space Temperature (SPT) Sensors . . . . . . . . . . . . 36  
Indoor Air Quality (CO2) Sensor . . . . . . . . . . . . . 36  
Two Position Damper Hood Removal and Setup —  
Factory Option . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9  
Economizer Hood and Two-Position Hood . . . . . 10  
Step 9 - Install Flue Hood . . . . . . . . . . . . . . . . . . . . . 10  
Step 10 - Install Gas Piping . . . . . . . . . . . . . . . . . . . . 11  
Factory-Option Thru-Base Connections  
(Gas Connections) . . . . . . . . . . . . . . . . . . . . . . . . . 11  
Step 11 - Install External Condensate Trap and Line . . 13  
Step 12 - Make Electrical Connections . . . . . . . . . . . 14  
Field Power Supply . . . . . . . . . . . . . . . . . . . . . . . . 14  
All Units . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15  
Units without Factory-Installed Disconnect . . . . 15  
Vertical Connections / Economizer  
Horizontal Connections / Economizer  
C10864A  
Fig. 1 - Unit Dimensional Drawing – 16 Size Unit  
3
C10862A  
Fig. 1 - Unit Dimensional Drawing – 16 Size Unit (cont.)  
INSTALLATION  
Jobsite Survey  
18”  
(457)  
*
Complete the following checks before installation.  
42"  
(1067)  
1. Consult local building codes and the NEC (National  
Electrical Code) ANSI/NFPA 70 for special installa-  
tion requirements.  
2. Determine unit location (from project plans) or select  
unit location.  
42"  
(1067)  
42"  
(1067)  
3. Check for possible overhead obstructions which may  
interfere with unit lifting or rigging.  
Required bottom condensate drain connection.  
Otherwise, 36” (914mm) for condensate connection.  
*
Step 1 — Plan for Unit Location  
C09897  
Fig. 2 - Service Clearance Dimensional Drawing  
Select a location for the unit and its support system (curb  
or other) that provides for at least the minimum clearances  
required for safety. This includes the clearance to  
combustible surfaces, unit performance and service access  
below, around and above unit as specified in unit  
drawings. See Fig. 2.  
Although unit is weatherproof, avoid locations that permit  
water from higher level runoff and overhangs to fall onto  
the unit.  
Select a unit mounting system that provides adequate  
height to allow for removal and disposal of frost and ice  
that will form during the heating-defrost mode as well as  
allow installation of condensate trap per requirements.  
Refer to Step 11 — Install External Condensate Trap and  
Line – for required trap dimensions.  
NOTE: Consider also the effect of adjacent units.  
Unit may be installed directly on wood flooring or on Class  
A, B, or C roof-covering material when roof curb is used  
Do not install unit in an indoor location. Do not locate air  
inlets near exhaust vents, relief valves, or other sources of  
contaminated air.  
4
Roof Mount —  
Step 3 — Inspect Unit  
Inspect unit for transportation damage. File any claim  
with transportation agency.  
Check building codes for weight distribution  
requirements. Unit operating weight is shown in Table 1.  
Confirm before installation of unit that voltage, amperage  
and circuit protection requirements listed on unit data  
plate agree with power supply provided.  
Table 1 – Operating Weights  
48TC**16  
COMPONENT  
Base Unit  
UNITS LB (KG)  
Step 4 — Provide Unit Support  
Roof Curb Mount —  
1380 (627)  
Economizer  
Vertical  
100 (45)  
115 (52)  
62 (28)  
32 (15)  
Accessory roof curb details and dimensions are shown in  
Fig. 3. Assemble and install accessory roof curb in  
accordance with instructions shipped with the curb.  
Horizontal  
R
H u m id i --- MiZ e r System  
Powered Outlet  
Curb  
NOTE: The gasketing of the unit to the roof curb is  
critical for a watertight seal. Install gasket supplied with  
the roof curb as shown in Fig. 3. Improperly applied  
gasket can also result in air leaks and poor unit  
performance.  
14---in/356 mm  
24---in/610 mm  
180 (82)  
235 (107)  
Curb should be level. This is necessary for unit drain to  
function properly. Unit leveling tolerances are show in  
Fig. 4. Refer to Accessory Roof Curb Installation  
Instructions for additional information as required.  
Step 2 — Plan for Sequence of Unit Installation  
The support method used for this unit will dictate different  
sequences for the steps of unit installation. For example,  
on curb-mounted units, some accessories must be  
installed on the unit before the unit is placed on the curb.  
Review the following for recommended sequences for  
installation steps.  
Install insulation, cant strips, roofing felt, and counter  
flashing as shown. Ductwork must be attached to curb and  
not to the unit.  
IMPORTANT:  
Curb-mounted installation —  
If the unit’s gas connection and/or electric and control  
wiring is to be routed through the basepan and the unit  
is equipped with the factory-installed Thru-the-Base  
service option see the following sections:  
Install curb, making sure to position the common cross  
rail (see Fig. 3) for large duct opening.  
Install field-fabricated ductwork inside curb  
Complete installation of the factory-installed  
thru-the-base service connection option  
Prepare bottom condensate drain connection to suit  
planned condensate line routing (refer to Step 9 for  
details)  
S Factory-Option Thru-Base Connections  
(Gas Connection) on page 11  
S Factory-Option Thru-Base Connections  
(Electrical Connections) on page 17  
Rig and place unit  
If using the field-installed Thru-the-Base accessory  
follow the instructions provided with the accessory kit.  
Install outdoor air hood  
Install condensate line trap and piping  
Make electrical connections  
Install other accessories  
NOTE: If gas and/or electrical connections are not  
going to occur at this time, tape or otherwise cover the  
fittings so that moisture does not get into the building or  
conduit in the interim.  
Pad-mounted installation —  
Prepare pad and unit supports  
Slab Mount (Horizontal Units Only) —  
Check and tighten the bottom condensate drain  
connection plug  
Rig and place unit  
Convert unit to side duct connection arrangement  
Install field-fabricated ductwork at unit duct openings  
Install outdoor air hood  
Provide a level concrete slab that extends a minimum of  
6 in. (150 mm) beyond unit cabinet. Install a gravel apron  
in front of condenser coil air inlet to prevent grass and  
foliage from obstructing airflow.  
NOTE: Horizontal units may be installed on a roof curb  
Install condensate line trap and piping  
Make electrical connections  
Install other accessories  
if required.  
Alternate Unit Support  
(In Lieu of Curb or Slab Mount) —  
Frame-mounted installation —  
A non-combustible sleeper rail can be used in the unit curb  
support area. If sleeper rails cannot be used, support the long  
sides of the unit with a minimum of 3 equally spaced 4-in. x  
4-in. (102 mm x 102 mm) pads on each side.  
Frame-mounted applications generally follow the  
sequence for a curb installation. Adapt as required to  
suit specific installation plan.  
5
C10772  
Fig. 3 - Roof Curb Details  
6
!
CAUTION  
PROPERTY DAMAGE HAZARD  
C
Failure to follow this caution may result in damage  
to roofing materials.  
Membrane roofs can be cut by sharp sheet metal  
edges. Be careful when placing any sheet metal parts  
on such roof.  
MAXIMUM ALLOWABLE  
DIFFERENCE IN. (MM)  
A
B
A-B  
0.5” (13)  
B-C  
1.0” (25)  
A-C  
1.0” (25)  
C10001  
Step 6 — Rig and Place Unit  
Fig. 4 - Unit Leveling Tolerances  
Step 5 — Field Fabricate Ductwork  
NOTE: Cabinet return-air static pressure (a negative  
condition) shall not exceed 0.35 in. wg (87 Pa) with  
economizer or 0.45 in. wg (112 Pa) without economizer.  
When the unit is ready to be rigged and no longer will be  
lifted by a fork truck, the wood protector under the basepan  
must be removed. Remove 4 screws from each base rail.  
Wood protector will drop to the ground. See instructions on  
the unit base rails.  
Keep unit upright and do not drop. Spreader bars are  
required. Rollers may be used to move unit across a roof.  
Level by using unit frame as a reference. See Table 1 and  
Fig. 5 for additional information.  
For vertical ducted applications, secure all ducts to roof curb  
and building structure. Do not connect ductwork to unit.  
Fabricate supply ductwork so that the cross sectional  
dimensions are equal to or greater than the unit supply  
duct opening dimensions for the first 18 in. (458 mm) of  
duct length from the unit basepan.  
Lifting holes are provided in base rails as shown in Fig. 5.  
Refer to rigging instructions on unit.  
Insulate and weatherproof all external ductwork, joints,  
and roof openings with counter flashing and mastic in  
accordance with applicable codes.  
!
CAUTION  
UNIT DAMAGE HAZARD  
Ducts passing through unconditioned spaces must be  
insulated and covered with a vapor barrier.  
Failure to follow this caution may result in  
equipment damage.  
All panels must be in place when rigging. Unit is not  
designed for handling by fork truck.  
If a plenum return is used on a vertical unit, the return  
should be ducted through the roof deck to comply with  
applicable fire codes.  
Before setting the unit onto the curb, recheck gasketing on  
curb.  
PLACE ALL SEAL STRIP IN PLACE BEFORE PLACING  
UNIT ON ROOF CURB.  
914 - 1371  
( 36” - 54” )  
“B”  
“C”  
DUCT END  
DETAIL “A”  
“A”  
SEE DETAIL “A”  
C10774  
DIMENSIONS  
MAX WEIGHT  
A
B
C
UNIT  
LB  
2130  
KG  
IN  
MM  
IN  
MM  
IN  
MM  
48TC**16  
NOTES:  
968  
116.0  
2945  
60.5  
1535  
59.5  
1510  
1. SPREADER BARS REQUIRED — Top damage will occur if spreader bars are not used.  
2. Dimensions in ( ) are in millimeters.  
3. Hook rigging shackles through holes in base rail, as shown in detail A.” Holes in base rails are centered around  
the unit center of gravity. Use wooden top to prevent rigging straps from damaging unit.  
Fig. 5 - Rigging Details  
7
Positioning on Curb —  
Remove all shipping materials and top skid. Remove extra  
center post from the condenser end of the unit so that the  
condenser end of the unit matches Figs. 26 and 27.  
Recycle or dispose of all shipping materials.  
For full perimeter curbs CRRFCURB074A00 and 075A00,  
the clearance between the roof curb and the front and rear  
1
base rails should be /4 in (6.4 mm). The clearance between  
the curb and the end base rails should be 1/2 in (13 mm). For  
retrofit applications with curbs CRRFCURB003A01 and  
Step 7 — Convert to Horizontal and Connect  
Ductwork (when required)  
4A01, the unit should be position as shown in Fig. 6.  
Unit is shipped in the vertical duct configuration. Unit  
without factory-installed economizer or return air smoke  
detector option may be field-converted to horizontal ducted  
configuration using accessory CRDUCTCV001A00. To  
convert to horizontal configuration, remove screws from side  
duct opening covers and remove covers.  
5
Maintain the 15.5 in (394 mm) and 8  
/
8
in (220 mm)  
clearances and allow the 22 5/16 in (567 mm) dimension to  
float if necessary.  
Discard the supply duct cover. Install accessory  
CRDUCTCV001A00 to cover the vertical supply duct  
opening. Use the return duct cover removed from the end  
panel to cover the vertical return duct opening.  
C10003  
Field-supplied flanges should be attached to horizontal  
duct openings and all ductwork should be secured to the  
flanges. Insulate and weatherproof all external ductwork,  
joints, and roof or building openings with counter flashing  
and mastic in accordance with applicable codes.  
Fig. 6 - Retrofit Installation Dimensions  
If the alternative condensate drain location through the  
bottom of the unit is used in conjunction with a retrofit  
curb, the hole in the curb must be moved 12.5 in (320  
mm) towards the duct end of the unit. (See Fig. 7.)  
Do not cover or obscure visibility to the unit’s informative  
data plate when insulating horizontal ductwork.  
Original  
Position  
New Position  
(moved 12.5 in.)  
C10904  
Fig. 7 - Alternative Condensate Drain Hole Positions  
Although unit is weatherproof, guard against water from  
higher level runoff and overhangs.  
C06108  
Fig. 8 - Horizontal Conversion Panels  
IMPORTANT:  
If the unit has the factory-installed Thru-the-Base  
option, make sure to complete installation of the option  
before placing the unit on the roof curb.  
See the following sections:  
S Factory-Option Thru-Base Connections  
(Gas Connection) on page 11  
S Factory-Option Thru-Base Connections  
(Electrical Connections) on page 17  
NOTE: If gas and/or electrical connections are not  
going to occur at this time, tape or otherwise cover the  
fittings so that moisture does not get into the building or  
conduit in the interim.  
8
Two Position Damper Hood Removal and Setup -  
Factory Option —  
Step 8 — Install Outside Air Hood  
Economizer Hood Removal and Setup -  
Factory Option —  
1. The hood is shipped in knock-down form and  
assembled to a metal support tray using plastic stretch  
wrap. Located in the return air compartment, the  
assembly’s metal tray is attached to the basepan and  
also attached to the damper using two plastic  
tie-wraps.  
1. The hood is shipped in knock-down form and located  
in the return air compartment. It is attached to the  
economizer using two plastic tie-wraps.  
2. To gain access to the hood, remove the filter access  
panel. (See Fig. 9.)  
3. Locate and cut the (2) plastic tie-wraps, being careful  
to not damage any wiring. (See Fig. 10.)  
4. Carefully lift the hood assembly through the filter  
access opening and assemble per the steps outlined in  
Economizer Hood and Two–Position Hood on page 10.  
2. To gain access to the hood, remove the filter access  
panel. (See Fig. 9.)  
3. Locate the (2) screws holding the metal tray to the  
basepan and remove. In order to remove the screws, it  
may be necessary to remove the panel underneath the  
two-position damper. Remove the two screws. Locate  
and cut the (2) plastic tie-wraps securing the  
assembly to the damper. (See Fig. 11.) Be careful to  
not damage any wiring or cut tie-wraps securing any  
wiring.  
4. Carefully lift the hood assembly (with metal tray)  
through the filter access opening and assemble per the  
steps outlined in Economizer Hood and Two–Position  
Hood on page 10.  
5. If removed, reattach the panel under the damper.  
FILTER ACCESS PANEL  
Hood Parts  
INDOOR COIL ACCESS PANEL  
C10004  
Fig. 9 - Typical Access Panel Locations  
Plastic Tie Wrap  
Qty (2)  
Remove Hood Parts  
Screws for Metal Tray  
Qty (2)  
Cut Plastic Ties  
(2) Places  
C10006  
Fig. 11 - Two-Position Damper Hood Package Location  
Economizer  
C10005  
Fig. 10 - Economizer Hood Package Location  
9
Economizer Hood and Two-Position Hood —  
5. Attach the post that separates the filters with the  
screws provided.  
6. Open the filter clips which are located underneath the  
hood top. Insert the aluminum filters into the bottom  
filter rack (hood divider). Push the filter into position  
past the open filter clips. Close the filter clips to lock  
the filters into place. See Fig. 14.  
NOTE: If the power exhaust accessory is to be installed  
on the unit, the hood shipped with the unit will not be  
used and must be discarded. Save the aluminum filter for  
use in the power exhaust hood assembly.  
1. The indoor coil access panel will be used as the top of  
the hood. If the panel is still attached to the unit, re-  
move the screws along the sides and bottom of the  
panel. See Fig. 12.  
7. Install the two rain deflectors on the edge of the hood  
top as shown in Fig. 12.  
SIDE  
PANEL  
DIVIDER  
OUTSIDE  
AIR  
RAIN DEFLECTORS  
HOOD  
CLEANABLE  
ALUMINUM  
FILTER  
TOP  
PANEL  
CAULK  
HERE  
BAROMETRIC  
FILTER  
RELIEF  
FILTER  
CLIP  
INDOOR  
COIL  
ACCESS  
PANEL  
INDOOR  
COIL  
ACCESS  
PANEL  
C10009  
Fig. 14 - Economizer Filter Installation  
C10007  
8. Caulk the ends of the joint between the unit top panel  
and the hood top as shown in Fig. 12.  
Fig. 12 - Indoor Coil Access Panel Relocation  
2. Swing out indoor coil access panel and insert the  
hood sides under the panel (hood top). Be careful not  
to lift the panel too far as it might fall out. Use the  
screws provided to attach the hood sides to the hood  
top. Use screws provided to attach the hood sides to  
the unit. See Fig. 13.  
9. Replace the filter access panel.  
Step 9 — Install Flue Hood  
The flue hood is shipped screwed to the basepan beside  
the burner compartment access panel. Remove the panel  
below the control box access panel to access the flue hood  
shipping location. Using screws provided, install flue  
hood and screen in location shown in Fig. 15.  
TOP  
PANEL  
INDOOR COIL  
ACCESS PANEL  
SCREW  
LEFT  
HOOD  
SIDE  
HOOD DIVIDER  
C10008  
CONTROL BOX  
ACCESS PANEL  
Fig. 13 - Economizer Hood Construction  
FLUE  
HOOD  
3. Remove the shipping tape holding the economizer  
barometric relief damper in place.  
C10804  
4. Insert the hood divider between the hood sides. See  
Figs. 13 and 14. Secure hood divider with 3 screws on  
each hood side. The hood divider is also used as the  
bottom filter rack for the aluminum filter.  
Fig. 15 - Flue Hood Details  
10  
X
Step 10 — Install Gas Piping  
9” MINIMUM CLEARANCE  
FOR PANEL REMOVAL  
Installation of the gas piping must be accordance with  
local building codes and with applicable national codes.  
In U.S.A., refer to NFPA 54/ANSI Z223.1 National Fuel  
Gas Code (NFGC). In Canada, installation must be  
accordance with the CAN/CSA B149.1 and CAN/CSA  
B149.2 installation codes for gas burning appliances.  
GAS  
FROM  
GAS  
REGULATOR  
*
MANUAL GAS  
METER  
SHUTOFF VALVE  
*
BASE UNIT  
48” MINIMUM  
DRIP LEG  
PER NFGC  
*
This unit is factory equipped for use with Natural Gas fuel  
at elevations up to 2000 ft (610 m) above sea level. Unit  
may be field converted for operation at elevations above  
2000 ft (610 m) and/or for use with liquefied petroleum  
fuel. See accessory kit installation instructions regarding  
these accessories.  
BASE RAIL  
FIELD-  
ROOF  
CURB  
FABRICATED  
SUPPORT  
*
LEGEND  
NFGC – National Fuel Gas Code  
Field supplied.  
*
NOTE: Follow all local codes.  
STEEL PIPE  
SPACING OF SUPPORTS  
NOTE: In U.S.A. the input rating for altitudes above 2000  
ft (610 m) must be derated by 4% for each 1000 ft (305 m)  
above sea level. In Canada the input rating must be derated  
by 10% for altitudes of 2000 ft (610 m) to 4500 ft. (1372 m)  
above sea level.  
For natural gas applications, gas pressure at unit gas  
connection must not be less than 5 in. wg (1250 Pa) or  
greater than 13 in. wg (3240 Pa) while the unit is operating.  
For liquified petroleum applications, the gas pressure must  
not be less than 11 in. wg (2740 Pa) or greater than 13 in.  
wg (3240 Pa) at the unit connection.  
The gas supply pipe enters the unit at the burner access  
panel on the front side of the unit, through the long slot at  
the bottom of the access panel. The gas connection to the  
unit is made to the 3/4-in. FPT gas inlet port on the unit gas  
valve.  
NOMINAL DIAMETER  
(in.)  
X DIMENSION  
(ft)  
1
/
2
6
8
3
/
4 or 1  
11/4 or larger  
10  
C11121  
Fig. 16 - Gas Piping Guide  
Factory-Option Thru-Base Connections  
(Gas Connection) —  
This service connection kit consists of a 3/4-in NPT gasadapter  
1
fitting (stainless steel), a /2-in electrical bulkhead connector  
and a 11/2-in electrical bulkhead connector, connected to an  
“L” bracket covering the embossed (raised) section of the unit  
basepan in the condenser section. See Fig. 17.  
1
2
/ ” ELECTRICAL  
BULKHEAD  
1
2
1 / ” ELECTRICAL  
BULKHEAD  
CONNECTOR  
CONNECTOR  
Table 2 – Natural Gas Supply Line Pressure Ranges  
3
4
/ ” NPT GAS  
UNIT  
MIN  
MAX  
ADAPTER  
FITTING  
48HC**14  
5.0 in. wg (1250 Pa) 13.0 in. wg (3240 Pa)  
!
CAUTION  
EQUIPMENT DAMAGE HAZARD  
Failure to follow this caution may result in damage  
to equipment.  
When connecting the gas line to the unit gas valve,  
the installer MUST use a backup wrench to prevent  
damage to the valve.  
C10905  
Fig. 17 - Thru-the-Base Option, Shipping Position  
1. Remove the “L” bracket assembly from the unit (see  
Fig. 17).  
2. Cut and discard the wire tie on the gas fitting. Hand  
tighten the fitting if it has loosened in transit.  
3. Remove connector plate assembly from the “L”  
bracket and discard the “L” bracket, but retain the  
washer head screws and the gasket (located between  
the “L” bracket and the connector plate assembly  
NOTE: Take care not to damage the gasket, as it is  
reused in the following step.  
4. Place the gasket over the embossed area in the  
basepan, aligning the holes in the gasket to the holes  
in the basepan. See Fig. 18.  
Install a gas supply line that runs to the unit heating  
section. Refer to the NFPA 54/NFGC or equivalent code  
for gas pipe sizing data. Size the gas supply line to allow  
for a maximum pressure drop of 0.5-in wg (124 Pa)  
between gas regulator source and unit gas valve  
connection when unit is operating at high-fire flow rate.  
The gas supply line can approach the unit in three ways:  
horizontally from outside the unit (across the roof),  
thru-curb/under unit basepan (accessory kit required) or  
through unit basepan (factory-option or accessory kit  
required). Consult accessory kit installation instructions  
for details on these installation methods. Observe  
clearance to gas line components per Fig. 16.  
5. Install the connector plate assembly to the basepan  
using 8 of the washer head screws.  
11  
NOTE: If gas and/or electrical connections are not going to  
occur at this time, tape or otherwise cover the fittings so that  
moisture does not get into the building or conduit in the  
interim.  
shutoff valve be located upstream of the sediment trap.  
See Figs. 20 and 21 for typical piping arrangements for  
gas piping that has been routed through the sidewall of the  
curb. See Fig. 22 for typical piping arrangement when  
thru-base is used. Ensure that all piping does not block  
access to the unit’s main control box or limit the required  
working space in front of the control box.  
CONNECTOR  
PLATE  
ASSEMBLY  
9” (229mm) min  
Thru-Curb Adapter  
Union  
GASKET  
Unit Base Rail  
Shut Off  
Valve  
C10906  
Fig. 18 - Completing Installation of Thru-the-Base  
Option  
Drip  
Leg  
C07469  
The thru-base gas connector has male and female threads.  
The male threads protrude above the basepan of the unit;  
the female threads protrude below the basepan.  
Fig. 20 - Gas Piping  
Check tightness of connector lock nuts before connecting  
gas piping.  
9” (229mm) min  
3
Install a /4 -in NPT street elbow (field-supplied) on the  
Burner  
Access  
Panel  
thru-base gas fitting. Attach a 3/4 -in pipe nipple with  
minimum length of 16-in (406 mm) (field-supplied) to  
the street elbow and extend it through the access panel at  
the gas support bracket. (See Fig. 19.)  
Union  
Thru-Curb Adapter  
Unit Base Rail  
Drip  
Leg  
Shut Off  
Valve  
C07470  
GAS  
SUPPORT  
BRACKET  
3
Fig. 21 - Gas Piping  
/ -in NPT  
4
THRU-BASE  
GAS FITTING  
STREET  
ELBOW  
C10806  
Fig. 19 - Gas Line Piping  
Other hardware required to complete the installation of  
the gas supply line will include a manual shutoff valve, a  
sediment trap (drip leg) and a ground-joint union. A  
pressure regulator valve may also be required (to convert  
gas pressure from pounds to inches of pressure). The  
manual shutoff valve must be located within 6-ft (1.83 m)  
of the unit. The union, located in the final leg entering the  
unit, must be located at least 9-in (230 mm) away from  
the access panel to permit the panel to be removed for  
service. If a regulator valve is installed, it must be located  
a minimum of 4-ft (1220 mm) away from the unit’s flue  
outlet. Some municipal codes require that the manual  
Fig. 22 - Gas Piping Thru-Base ConnectionsC10826  
12  
When installing the gas supply line, observe local codes  
pertaining to gas pipe installations. Refer to the NFPA  
54/ANSI Z223.1 NFGC latest edition (in Canada, CAN/CSA  
B149.1). In the absence of local building codes, adhere to  
the following pertinent recommendations:  
1. Avoid low spots in long runs of pipe. Grade all pipe  
1/4-in. in every 15 ft (7 mm in every 5 m) to prevent  
traps. Grade all horizontal runs downward to risers.  
Use risers to connect to heating section and to meter.  
2. Protect all segments of piping system against physical  
and thermal damage. Support all piping with appro-  
priate straps, hangers, etc. Use a minimum of one  
hanger every 8 ft (2.4 m). For pipe sizes larger than  
3/4-in., follow recommendations of national codes.  
BURNER  
ORIFICE  
3. Apply joint compound (pipe dope) sparingly and only  
to male threads of joint when making pipe connec-  
tions. Use only pipe dope that is resistant to action of  
liquefied petroleum gases as specified by local and/or  
national codes. If using PTFE (Teflon) tape, ensure  
the material is Double Density type and is labeled for  
use on gas lines. Apply tape per manufacturer’s in-  
structions.  
A93059  
Fig. 23 - Orifice Hole  
NOTE: If orifice hole appears damaged or it is suspected  
to have been re-drilled, check orifice hole with a  
numbered drill bit of correct size. Never re-drill an  
orifice. A burr-free and squarely aligned orifice hole is  
essential for proper flame characteristics. See Fig. 23.  
4. Pressure-test all gas piping in accordance with local  
and national plumbing and gas codes before connect-  
ing piping to unit.  
Step 11 — Install External Condensate Trap and  
Line  
NOTE: Pressure test the gas supply system after the gas  
supply piping is connected to the gas valve. The supply  
piping must be disconnected from the gas valve during the  
testing of the piping systems when test pressure is in  
excess of 0.5 psig (3450 Pa). Pressure test the gas supply  
piping system at pressures equal to or less than 0.5 psig  
(3450 Pa). The unit heating section must be isolated from  
the gas piping system by closing the external main manual  
shutoff valve and slightly opening the ground-joint union.  
3
The unit has one /4-in. condensate drain connection on  
the end of the condensate pan and an alternate connection  
on the bottom. See Fig. 24. Unit airflow configuration  
does not determine which drain connection to use. Either  
drain connection can be used with vertical or horizontal  
applications.  
Check for gas leaks at the field-installed and  
factory-installed gas lines after all piping connections  
have been completed. Use soap-and-water solution (or  
method specified by local codes and/or regulations).  
!
CONDENSATE PAN (SIDE VIEW)  
WARNING  
ALTERNATE  
BOTTOM DRAIN  
STANDARD  
SIDE DRAIN  
DRAIN PLUG  
(FACTORY-INSTALLED)  
FIRE OR EXPLOSION HAZARD  
C08021  
Failure to follow this warning could result in personal  
injury, death and/or property damage.  
Fig. 24 - Condensate Drain Pan (Side View)  
S Connect gas pipe to unit using a backup wrench to  
avoid damaging gas controls.  
S Never purge a gas line into a combustion chamber.  
S Never test for gas leaks with an open flame. Use a  
commercially available soap solution made  
specifically for the detection of leaks to check all  
connections.  
When using the standard side drain connection, ensure the  
red plug in the alternate bottom connection is tight. Do  
this before setting the unit in place. The red drain pan can  
be tightened with a 1/2 -in. square socket drive extension.  
To use the alternate bottom drain connection, remove the  
1
red drain plug from the bottom connection (use a /2 - i n .  
S Use proper length of pipe to avoid stress on gas  
control manifold.  
square socket drive extension) and install it in the side  
drain connection.  
13  
The piping for the condensate drain and external trap can  
be completed after the unit is in place. See Fig. 25.  
MINIMUM PITCH  
1” (25mm) PER  
10’ (3m) OF LINE  
BASE RAIL  
2˝ (51) MIN  
OPEN  
VENT  
TO ROOF  
DRAIN  
SEE NOTE  
C10884  
Fig. 26 - Conduit into Factory Option Disconnect  
ROOF  
CURB  
DRAIN PLUG  
NOTE: Trap should be deep enough to offset maximum unit static  
difference. A 4” (102) trap is recommend. ed  
C08022  
Fig. 25 - Condensate Drain Piping Details  
All units must have an external trap for condensate  
drainage. Install a trap at least 4-in. (102 mm) deep and  
protect against freeze-up. If drain line is installed  
downstream from the external trap, pitch the line away  
from the unit at 1-in. per 10 ft (25 mm in 3 m) of run. Do  
not use a pipe size smaller than the unit connection  
(3/4-in.).  
C10885  
Fig. 27 - Conduit into Control Box  
Step 12 — Make Electrical Connections  
If the field disconnect is larger than 100A, it must be  
attached to the unit using accessory CRDISBKT001A00  
— disconnect switch bracket — (see Fig. 28). Follow the  
instructions provided with this accessory. For smaller field  
disconnects, be sure to use 1/2” screws to mount the  
disconnect directly to the end panel (see Fig. 29). In either  
case, set the disconnect vertical location on the unit so  
that a 90_ fitting can be used to connect the conduit to the  
disconnect.  
!
WARNING  
ELECTRICAL SHOCK HAZARD  
Failure to follow this warning could result in personal  
injury or death.  
Do not use gas piping as an electrical ground. Unit  
cabinet must have an uninterrupted, unbroken electrical  
ground to minimize the possibility of personal injury if  
an electrical fault should occur. This ground may consist  
of electrical wire connected to unit ground lug in control  
compartment, or conduit approved for electrical ground  
when installed in accordance with NEC (National  
Electrical Code); ANSI/NFPA 70, latest edition (in  
Canada, Canadian Electrical Code CSA [Canadian  
Standards Association] C22.1), and local electrical  
codes.  
NOTE: Field-supplied wiring shall conform with the  
limitations of minimum 63_F (33_C) rise.  
Field Power Supply —  
For those units without through-the-curb power, conduit  
must be used to route the main power from the condenser  
end, via the power entry in the corner post of the unit (see  
Figs. 26 and 27) to either the factory option disconnect or  
the bottom of the control box. 1” conduit is provided  
wrapped around compressor. A second conduit is provided  
with factory installed powered convenience outlet. For those  
units that require conduit larger than 1”, it must be field  
supplied. Figs. 26 and 27 show the wire routings.  
C10853  
Fig. 28 - Mounting Position for Field Disconnects  
(over 100A)  
14  
All Units —  
All field wiring must comply with NEC and all local  
requirements. Size wire based on MCA (Minimum Circuit  
Amps) on the unit informative plate. See Fig. 31 and the  
unit label diagram for power wiring connections to the  
unit power terminal blocks and equipment ground.  
Maximum wire size is 2/0 AWG per pole.  
Provide a ground-fault and short-circuit over-current  
protection device (fuse or breaker) per NEC Article 440  
(or local codes). Refer to unit informative data plate for  
MOCP (Maximum Over-current Protection) device size.  
Voltage to compressor terminals during operation must be  
within voltage range indicated on unit nameplate. See  
Table 10. On 3-phase units, voltages between phases must  
be balanced within 2% and the current within 10%. Use  
the formula shown in the legend for Table 10 (see Note 2  
on page 45) to determine the percent of voltage  
imbalance.  
C10854  
Fig. 29 - Mounting Position for Field Disconnects  
(up to 100A)  
All units except 208/230-v units are factory wired for the  
voltage shown on the nameplate. If the 208/230-v unit is  
to be connected to a 208-v power supply, the control  
transformer must be rewired by moving the black wire  
with the 1/4-in. female spade connector from the 230-v  
connection and moving it to the 200-v 1/4-in. male  
terminal on the primary side of the transformer. Refer to  
unit label diagram for additional information.  
Field power wires are connected to the unit at line-side  
pressure lugs at the main terminal block (TB1) or at  
factory-installed option non-fused disconnect switch.  
Max wire size is #2 AWG (copper only). (See Fig. 31.)  
NOTE: TEST LEADS - Unit may be equipped with  
short leads (pigtails) on the field line connection points off  
the optional disconnect switch. These leads are for factory  
run-test purposes only; remove and discard before  
connecting field power wires to unit connection points.  
Make field power connections directly to line connection  
pressure lugs only.  
!
CAUTION  
UNIT DAMAGE HAZARD  
Failure to follow this caution may result in equipment  
damage.  
!
WARNING  
Operation on improper line voltage or excessive phase  
imbalance constitutes abuse and may cause damage to  
electrical components. Such operation would invalidate  
any applicable Carrier warranty.  
FIRE HAZARD  
Failure to follow this warning could result in  
intermittent operation or performance satisfaction.  
Do not connect aluminum wire between disconnect  
switch and unit. Use only copper wire.  
(See Fig. 30.)  
NOTE: Check all factory and field electrical connections  
for tightness.  
Units Without Factory-Installed Disconnect —  
When installing units, provide a disconnect switch of  
adequate size per NEC (National Electrical Code).  
Disconnect sizing data is provided on the unit informative  
plate. Locate on unit cabinet or within sight of the unit per  
national or local codes. Do not cover unit informative  
plate if mounting the disconnect on the unit cabinet.  
ELECTRIC  
DISCONNECT  
SWITCH  
COPPER  
WIRE ONLY  
Units with Factory-Installed Disconnect —  
The factory-installed option disconnect switch is located in a  
weatherproof enclosure located under the main control box.  
The manual switch handle is accessible through an opening  
in the access panel. Discard the factory test leads (see Fig.  
31). The factory disconnect is an 80A disconnect.  
ALUMINUM  
WIRE  
A93033  
Fig. 30 - Disconnect Switch and Unit  
15  
Non-powered type: This type requires the field  
installation of a general-purpose 125-volt 15-A circuit  
powered from a source elsewhere in the building. Observe  
national and local codes when selecting wire size and  
conduit requirements, fuse or breaker requirements and  
disconnect switch size and location. Route 125-v power  
supply conductors into the bottom of the utility box  
containing the duplex receptacle.  
Units Without Disconnect Option  
TB1  
11  
12  
13  
Disconnect  
per  
NEC  
L1  
L2  
L3  
Unit-powered type: A unit-mounted transformer is  
factory-installed to stepdown the main power supply  
voltage to the unit to 115-v at the duplex receptacle. This  
option also includes a manual switch with fuse, located in  
a utility box and mounted on a bracket behind the  
convenience outlet; access is through the panel beneath  
the control box. See Fig. 32.  
208/230-3-60  
460-3-60  
575-3-60  
Units With Disconnect Option  
L1  
2
1
Optional  
Disconnect  
Switch  
Factory  
Wiring  
The primary leads to the convenience outlet transformer  
are not factory-connected. Selection of primary power  
source is a customer-option. If local codes permit, the  
transformer primary leads can be connected at the  
line-side terminals on the unit-mounted non-fused  
disconnect; this will provide service power to the unit  
when the unit disconnect switch is open. Other connection  
methods will result in the convenience outlet circuit being  
de-energized when the unit disconnect switch is open. See  
Fig. 34. On a unit without a unit-mounted disconnect,  
connect the source leads to the main terminal block  
(TB1).  
L2  
L3  
4
6
3
5
Disconnect factory test leads; discard.  
C10015  
Fig. 31 - Power Wiring Connections  
Convenience Outlets —  
!
WARNING  
ELECTRICAL OPERATION HAZARD  
Failure to follow this warning could result in personal  
injury or death.  
If the convenience outlet transformer is connected to the  
line side of a field disconnect, the conduit provided with  
the unit must be used to protect the wire as they are routed  
from the transformer to the field disconnect. The end of  
the conduit with the straight connector attaches to the  
field disconnect. The other end does not need to connect  
to the transformer; however, the conduit must be routed so  
that all wiring is either in the conduit or behind the access  
panel.  
Units with convenience outlet circuits may use  
multiple disconnects. Check convenience outlet for  
power status before opening unit for service. Locate  
its disconnect switch, if appropriate, and open it.  
Lock-out and tag-out this switch, if necessary.  
If the convenience outlet transformer is connected to the  
line side of the factory disconnect option, route the wires  
through the web bushing located on the bottom of the  
disconnect box. For the load side wiring to the factory  
option disconnect, route the wires through the hole on the  
right side of the disconnect. Be sure to create a drip loop  
at least 6” long.  
Two types of convenience outlets are offered on the  
48TC**16 : non-powered and unit-powered. Both types  
provide a 125-volt GFCI (ground-fault circuit-interrupter)  
duplex receptacle rated at 15-A behind a hinged waterproof  
access cover, located on the panel beneath the control box.  
See Fig. 32.  
Pwd-CO  
Fuse  
Switch  
NOTICE/AVIS  
Convenience Outlet Utilization  
Maximum Intermittent Use 15 - Amps  
Maximum Continuous Use 8 - Amps  
Observe a 50% limit on the circuit  
Loading above 8 - Amps  
Utilisation de la prise utilitaire  
Usage intermittent maximum 15 - Amps  
Usage continu maximum 8 - Amps  
Observez une limite de 50% sur le circuit  
Chargement au-dessus de 8 - Amps  
50HE501288 2.0  
Pwd-CO  
Transformer  
C10077  
Convenience  
Outlet  
GFCI  
Fig. 33 - Convenience Outlet Utilization Notice  
Disconnect  
Access Panel  
C10361  
Fig. 32 - Convenience Outlet Location  
16  
Test the GFCI receptacle by pressing the TEST button on  
the face of the receptacle to trip and open the receptacle.  
Check for proper grounding wires and power line phasing  
if the GFCI receptacle does not trip as required. Press the  
RESET button to clear the tripped condition.  
Installing Weatherproof Cover:  
A
weatherproof  
while-in-use cover for the factory-installed convenience  
outlets is now required by UL standards. This cover cannot  
be factory-mounted due its depth; it must be installed at unit  
installation. For shipment, the convenience outlet is covered  
with a blank cover plate.  
The weatherproof cover kit is shipped in the unit’s control  
box. The kit includes the hinged cover, a backing plate and  
gasket.  
DISCONNECT ALL POWER TO UNIT AND  
CONVENIENCE OUTLET. LOCK-OUT AND TAG-OUT  
ALL POWER.  
Remove the blank cover plate at the convenience outlet;  
discard the blank cover.  
Loosen the two screws at the GFCI duplex outlet, until  
approximately 1/2-in (13 mm) under screw heads are  
exposed. Press the gasket over the screw heads. Slip the  
backing plate over the screw heads at the keyhole slots  
and align with the gasket; tighten the two screws until  
snug (do not over-tighten).  
C08283  
Mount the weatherproof cover to the backing plate as  
shown in Fig. 35. Remove two slot fillers in the bottom of  
the cover to permit service tool cords to exit the cover.  
Check for full closing and latching.  
UNIT  
CONNECT  
AS  
PRIMARY  
TRANSFORMER  
TERMINALS  
VOLTAGE  
CONNECTIONS  
208,  
230  
L1: RED +YEL  
L2: BLU + GRA  
H1 + H3  
H2 + H4  
240  
480  
600  
COVER – WHILE-IN-USE  
RECEPTACLE  
L1: RED  
Splice BLU + YEL  
L2: GRA  
H1  
H2 + H3  
H4  
WEATHERPROOF  
NOT INCLUDED  
460  
575  
L1: RED  
L2: GRA  
H1  
H2  
Fig. 34 - Unit Powered Convenience Outlet Wiring  
Fuse on power type: The factory fuse is a Bussman  
“Fusetron” T-15, non-renewable screw-in (Edison base)  
type plug fuse.  
!
WARNING  
BASE PLATE FOR  
GFCI RECEPTACLE  
ELECTRICAL OPERATION HAZARD  
C09022  
Failure to follow this warning could result in personal  
injury or death.  
Fig. 35 - Weatherproof Cover Installation  
Using unit-mounted convenience outlets: Units with  
unit-mounded convenience outlet circuits will often  
require that two disconnects be opened to de-energize  
all power to the unit. Treat all units as electrically  
energized until the convenience outlet power is also  
checked and de-energization is confirmed. Observe  
National Electrical Code Article 210, Branch Circuits,  
for use of convenience outlets.  
17  
Factory-Option Thru-Base Connections  
(Electrical Connections)—  
Check tightness of connector lock nuts before connecting  
electrical conduits.  
Field-supplied and field-installed liquid tight conduit  
connectors and conduit may be attached to the connectors  
on the basepan. Pull correctly rated high voltage and low  
voltage through appropriate conduits. Connect the power  
conduit to the internal disconnect (if unit is so equipped)  
or to the external disconnect (through unit side panel). A  
hole must be field cut in the main control box bottom on  
the left side so the 24-v control connections can be made.  
Connect the control power conduit to the unit control box  
at this hole.  
1
This service connection kit consists of a /2 -in electrical  
bulkhead connector and a 11/2 -in electrical bulkhead  
connector, connected to an “L” bracket covering the  
embossed (raised) section of the unit basepan in the  
condenser section. See Fig. 36. The 1/2 -in bulkhead  
connector enables the low-voltage control wires to pass  
through the basepan. The 11/2 -in electrical bulkhead  
connector allows the high-voltage power wires to pass  
through the basepan.  
Units without Thru-Base Connections —  
1
2
/ ” ELECTRICAL  
1. Install power wiring conduit through side panel open-  
ings. Install conduit between disconnect and control  
box.  
BULKHEAD  
CONNECTOR  
2. Install power lines to terminal connections as shown  
in Fig. 31.  
Field Control Wiring —  
1
2
1 / ” ELECTRICAL  
BULKHEAD  
The 48TC**16 requires an external temperature control  
device. This device can be a thermostat (field-supplied)  
or a PremierLink controller (available as factory-installed  
option or as field-installed accessory, for use on a Carrier  
Comfort Network or as a stand alone control) or the RTU  
Open Controller for Building Management Systems using  
non-CCN protocols (RTU Open is available as a  
factory-installed option only).  
CONNECTOR  
C10907  
Fig. 36 - Thru-the-Base Option, Shipping Position  
1. Remove the “L” bracket assembly from the unit.  
Thermostat —  
2. Remove connector plate assembly from the “L”  
bracket and discard the “L” bracket, but retain the  
washer head screws and the gasket (located between  
the “L” bracket and the connector plate assembly).  
NOTE: Take care not to damage the gasket, as it is  
reused in the following step.  
3. Place the gasket over the embossed area in the  
basepan, aligning the holes in the gasket to the holes  
in the basepan. See Fig. 37.  
4. Install the connector plate assembly to the basepan  
using 8 of the washer head screws.  
NOTE: If electrical connections are not going to occur at  
this time, tape or otherwise cover the fittings so that  
moisture does not get into the building or conduit in the  
interim.  
Install  
a
Carrier-approved accessory  
2
stage  
Cooling/Heating thermostat according to installation  
instructions included with the accessory. If using an  
electronic thermostat, configure it for “non-heat pump”  
operation. Locate the thermostat accessory on a solid wall  
in the conditioned space to sense average temperature in  
accordance with the thermostat installation instructions.  
If the thermostat contains a logic circuit requiring 24-v  
power, use a thermostat cable or equivalent single leads of  
different colors with minimum of seven leads. If the  
thermostat does not require a 24-v source (no “C”  
connection required), use a thermostat cable or equivalent  
with minimum of six leads. Check the thermostat  
installation instructions for additional features which  
might require additional conductors in the cable.  
CONNECTOR  
PLATE  
For wire runs up to 50 ft. (15 m), use no. 18 AWG  
(American Wire Gage) insulated wire (35_C minimum).  
For 50 to 75 ft. (15 to 23 m), use no. 16 AWG insulated  
wire (35_C minimum). For over 75 ft. (23 m), use no. 14  
AWG insulated wire (35_C minimum). All wire sizes  
larger than no. 18 AWG cannot be directly connected to  
the thermostat and will require a junction box and splice  
at the thermostat.  
ASSEMBLY  
GASKET  
C10908  
Fig. 37 - Completing Installation of Thru-the-Base  
Option  
18  
Unit without Thru-Base Connection Kit —  
Typical  
Thermostat  
Connections  
Central  
Terminal  
Board  
Pass the thermostat control wires through the bushing on the  
unit end panel. Route the wire through the snap-in wire tie  
and up to the web bushing near the control box.. Route the  
wire through the bushing and into the bottom left side of the  
control box after removing one of the two knockouts in the  
corner of the box. Use a connector at the control box to  
protect the wire as it passes into the control box. Pull the  
wires over to the terminal strip at the upper left corner of the  
Central Terminal Board (CTB). Use the connector at the  
control box and the wire tie to take up any slack in the  
thermostat wire to ensure that it will not be damaged by  
contact with the condenser coil. See Fig. 39.  
X
C
G
C
T
H
E
R
M
O
S
T
G
W2  
W1  
Y2  
Y1  
R
W2  
W1  
O/B/Y2  
(see Note)  
A
T
NOTE: If thru-the-bottom connections accessory is  
used, refer to the accessory installation instructions for  
information on routing power and control wiring.  
Y1  
R
Note: Typical multi-function marking. Follow manufacturer’s configuration  
instructions to select Y2. Do not configure for O output.  
Field Wiring  
C10903  
Fig. 38 - Typical Low-Voltage Control Connections  
Thermostat Wire  
C10886  
Fig. 39 - Thermostat Wire Routing  
Heat Anticipator Settings —  
Set heat anticipator settings at 0.14 amp for the first stage  
and 0.14 amp for second-stage heating, when available.  
19  
Humidi--MiZerR Control Connections  
Humidi-MiZer – Space RH Controller —  
NOTE: The Humidi-MiZer is a factory installed option.  
The Humidi-MiZer dehumidification system requires a  
field-supplied and -installed space relative humidity  
control device. This device may be a separate humidistat  
control (contact closes on rise in space RH above control  
setpoint) or a combination thermostat-humidistat control  
device such as Carrier’s EDGER Pro Thermidistat with  
isolated contact set for dehumidification control. The  
humidistat is normally used in applications where a  
temperature control is already provided (units with  
PremierLinkt control).  
% RELATIVE HUMIDITY  
C09295  
Fig. 40 - Accessory Field-Installed Humidistat  
To connect the Carrier humidistat (HL38MG029):  
1. Route the humidistat 2-conductor cable (field-supplied)  
through the bushing the unit’s louvered end panel (see  
Fig. 39).  
2. Route the cable through the snap-in wire tie and up to  
the web bushing near the control box.  
3. Feed the cable through the bushing and into the  
bottom left side of the control box after removing one  
of the two knockouts in the corner of the box. Use a  
connector to protect the cable as it enters the control  
box.  
4. Use the connector and the wire tie to reduce any slack  
in the humidistat cable to ensure that it will not be  
damaged by contact with the condenser coil (see Fig.  
39).  
5. Use wire nuts to connect humidistat cable to two  
PINK leads in the low–voltage wiring as shown in  
Fig. 42.  
®
To connect the Thermidistat device (33CS2PPRH-01):  
C09296  
1. Route the Thermidistat multi-conductor thermostat  
cable (field-supplied) through the bushing the unit’s  
louvered end panel (see Fig. 39).  
Fig. 41 - EDGE Pro Thermidistat  
2. Route the cable through the snap-in wire tie and up to  
the web bushing near the control box.  
3. Feed the cable through the bushing and into the  
bottom left side of the control box after removing one  
of the two knockouts in the corner of the box. Use a  
connector to protect the cable as it enters the control  
box.  
4. Use the connector and the wire tie to reduce any slack  
in the thermostat cable to ensure that it will not be  
damaged by contact with the condenser coil (see Fig.  
39).  
5. The Thermidistat has dry contacts at terminals D1  
and D2 for dehumidification operation (see Fig. 43).  
The dry contacts must be wired between CTB  
terminal R and the PINK lead to the LTLO switch  
with field-supplied wire nuts. Refer to the installation  
instructions included with the Carrier Edge  
Thermidistat device (Form 33CS-65SI or latest) for  
more information.  
20  
HUMIDISTAT  
C11201  
Fig. 42 - Typical Humidi-MiZerR Adaptive Dehumidification System Humidistat Wiring  
EDGE Pro THERMIDISTAT  
Unit CTB  
THERMOSTAT  
X*  
Rc  
Rh  
C
W1  
G
G
Y2  
W2  
C
O/W2/B  
Y1  
W1  
Y2  
Y1  
R
OAT  
RRS  
SRTN  
HUM  
D1  
Humidi-MiZer™ FIOP  
D2  
V+  
Vg  
*Connection not required.  
C09298  
Fig. 43 - Typical Rooftop Unit with Humidi-MiZer Adaptive Dehumidification System  
with EDGE Pro Thermidistat Device  
21  
PremierLinkt (Factory Option)  
C08199  
Fig. 44 - PremierLink Controller  
Refer to Form 33CS-67SI for complete  
NOTE:  
CTB. Field connections are made at a 16-pole terminal  
block (TB3) located on the bottom shelf of the unit  
control box in front of the PremierLink controller. The  
factory-installed PremierLink control includes the  
supply-air temperature (SAT) sensor. The outdoor air  
temperature (OAT) sensor is included in the  
FIOP/accessory EconoMi$ert2 package. (See page 34 for  
accessory enthalpy controls.)  
PremierLink configuration, operating sequences and  
troubleshooting information. Have a copy of this manual  
available at unit start-up.  
The PremierLink controller (see Fig. 44) is compatible  
with Carrier Comfort Networkr (CCN) devices. This  
control is designed to allow users the access and ability to  
change factory-defined settings, thus expanding the  
function of the standard unit control board. CCN service  
access tools include System Pilot (TM), Touch Pilot (TM)  
and Service Tool. (Standard tier display tools Navigatort  
and Scrolling Marquee are not suitable for use with latest  
PremierLink controller (Version 2.x).)  
The PremierLink controller requires the use of a Carrier  
electronic thermostat or a CCN connection for time  
broadcast to initiate its internal timeclock. This is  
necessary for broadcast of time of day functions  
(occupied/unoccupied).  
NOTE: PremierLink controller is shipped in Sensor mode.  
To be used with a thermostat, the PremierLink controller  
must be configured to Thermostat mode. Refer to  
PremierLink Configuration instructions for Operating Mode.  
The PremierLink control is factory-mounted in the  
48TC**16 unit’s main control box to the left of the  
Central Terminal Board (CTB) (see Fig. 45). Factory  
wiring is completed through harnesses connected to the  
C11189  
Fig. 45 - 48HC**14 Control Box Component Locations - PremierLink Controller Location  
22  
C11202  
Fig. 46 - PremierLink Wiring Schematic  
23  
C11203  
Fig. 47 - PremierLink Wiring Schematic with Humidi-MiZerR  
24  
Supply Air Temperature (SAT) Sensor —  
NOTE: The sensor must be mounted in the discharge  
airstream downstream of the cooling coil and any heating  
devices. Be sure the probe tip does not come in contact  
with any of the unit’s heater surfaces.  
On FIOP-equipped 48TC**16 units, the unit is supplied  
with a supply-air temperature (SAT) sensor (33ZCSENSAT).  
This sensor is a tubular probe type, approx 6-inches (12.7  
mm) in length. It is a nominal 10-k ohm thermistor.  
Outdoor Air Temperature (OAT) Sensor —  
The OAT is factory-mounted in the EconoMi$er2 (FIOP or  
accessory). It is a nominal 10k ohm thermistor attached to  
an eyelet mounting ring.  
The SAT is factory-wired. The SAT probe is wire-tied to  
the supply-air opening (on the horizontal opening end) in  
its shipping position. Remove the sensor for installation.  
Re-position the sensor in the flange of the supply-air  
opening or in the supply air duct (as required by local  
EconoMi$er2 —  
1
codes). Drill or punch a /2 -in. hole in the flange or duct.  
The PremierLink control is used with EconoMi$er2  
(option or accessory) for outdoor air management. The  
damper position is controlled directly by the PremierLink  
control; EconoMi$er2 has no internal logic device.  
Use the template provided in the unit control box. Use two  
field-supplied, self-drilling screws to secure the sensor  
probe in a horizontal orientation. See Fig. 48.  
Outdoor air management functions can be enhanced with  
field-installation of these accessory control devices:  
Enthalpy control (outdoor air or differential sensors)  
Space CO2 sensor  
Outdoor air CO2 sensor  
Refer to Table 3 for accessory part numbers.  
Field Connections  
Field connections for accessory sensor and input devices  
are made at the 16-pole terminal block (TB3) located  
beneath the PremierLink control (see Fig. 46). Some input  
devices also require a 24-vac signal source; connect at  
CTB terminal R at “THERMOSTAT” connection strip for  
this signal source. See connections figures on following  
pages for field connection locations (and for continued  
connections at the PremierLink board inputs). Route wires  
to control box as indicated in Fig. 39.  
SUPPLY AIR  
ROOF  
CURB  
TEMPERATURE  
SENSOR  
SUPPLY AIR  
RETURN AIR  
C10020  
Fig. 48 - Typical Mounting Location for Supply Air  
Temperature (SAT) Sensor on Small Rooftop Units  
NOTE:  
Refer to Form 33CS-67SI (or latest) for  
Table 4 provides a summary of field connections for units  
equipped with Space Sensor. Table 5 provides a summary of  
field connections for units equipped with Space Thermostat.  
complete PremierLink configuration, operating sequences  
and troubleshooting information. Have a copy of this  
manual available at unit set-up  
Table 3 – PremierLink Sensor Usage  
OUTDOOR AIR  
TEMPERATURE  
SENSOR  
RETURN AIR  
TEMPERATURE  
SENSOR  
OUTDOOR AIR  
ENTHALPY SENSOR  
RETURN AIR  
ENTHALPY SENSOR  
APPLICATION  
Differential Dry Bulb  
Temperature with  
PremierLink  
(PremierLink requires  
4 --- 20 m A A ctuator)  
R eq uired ---  
33ZCT55SPT  
or equivalent  
I nclud ed ---  
---  
---  
---  
CRTEMPSN001A00  
Single Enthalpy with  
PremierLink  
(PremierLink requires  
4 --- 20m A A ctuator)  
I nclud ed ---  
Not Used  
R eq uires ---  
33CSENTHSW  
---  
---  
Differential Enthalpy  
with PremierLink  
(PremierLink requires  
4 --- 20m A A ctuator)  
R eq uires ---  
33CSENTHSW  
or equivalent  
R eq uires ---  
33CSENTSEN  
or equivalent  
I nclud ed ---  
Not Used  
NOTES:  
CO Sensors (Optional):  
2
33ZCSENCO2 --- Room sensor (adjustable). Aspirator box is required for duct mounting of the sensor.  
33ZCASPCO2 --- Aspirator box used for duct---mounted CO room sensor.  
2
33ZCT55CO2 --- Space temperature and CO room sensor with override.  
2
33ZCT56CO2 --- Space temperature and CO room sensor with override and setpoint.  
2
25  
Table 4 – Space Sensor Mode  
TB3 TERMINAL  
FIELD CONNECTION  
T55 --- S E N /T56 --- S E N  
RMTOCC  
INPUT SIGNAL  
Analog (10k thermistor)  
Discrete, 24VAC  
1
2
3
T55 --- S E N /T56 --- S E N  
CMPSAFE  
Analog (10k thermistor)  
Discrete, 24VAC  
4
5
T56---SET  
Analog (10k thermistor)  
Discrete, 24VAC  
6
FSD  
7
LOOP---PWR  
Analog, 24VDC  
8
SPS  
Discrete, 24VAC  
9
IAQ---SEN  
A nalog, 4 --- 20m A  
Discrete, 24VAC  
10  
11  
12  
13  
14  
15  
16  
FILTER  
I A Q --- CO M /O A Q --- CO M /R H --- CO M  
CCN + (RED)  
OAQ---SEN/RH---SEN  
CCN Gnd (WHT)  
AUX OUT(Power Exhaust)  
CCN --- (BLK)  
A nalog, 4 --- 20m A  
Digital, , 5VDC  
A nalog, 4 --- 20m A  
Digital, 5VDC  
(Output)Discrete 24VAC  
Digital, 5VDC  
LEGEND:  
T 5 5  
T 5 6  
CCN  
C MP SA F E  
F ILT E R  
--- Sp a c e Te m p e r a t u r e S e n so r  
F S D --- F ir e S h u t d o w n  
IA Q --- In d o o r A ir Q u a lit y ( C O )  
OAQ --- Outdoor Air Quality (CO )  
2
R H --- R e la t iv e H u m id it y  
S F S --- S u p p ly Fa n S t a t u s  
--- Sp a c e Te m p e r a t u r e S e n so r  
--- Carrier Comfort Network (communication bus)  
--- C o m p r e sso r S a f e t y  
2
--- D i r t y F i lt e r S w i t c h  
Table 5 – Thermostat Mode  
TB3 TERMINAL  
FIELD CONNECTION  
INPUT SIGNAL  
Analog (10k thermistor)  
Discrete, 24VAC  
1
2
RAT SEN  
G
3
RAT SEN  
Y1  
Analog (10k thermistor)  
Discrete, 24VAC  
4
5
6
Y2  
LOOP---PWR  
Discrete, 24VAC  
Analog, 24VDC  
Discrete, 24VAC  
Analog, 4---20mA  
Discrete, 24VAC  
Analog, 4---20mA  
Digital, 5VDC  
7
8
W1  
9
I A Q --- S E N  
10  
11  
12  
13  
14  
15  
16  
W2  
I A Q --- CO M /O A Q --- CO M /R H --- CO M  
CCN + (RED)  
O A Q --- S E N /R H --- S E N  
CCN Gnd (WHT)  
AUX OUT (Power Exhaust)  
CCN --- (BLK)  
Analog, 4---20mA  
Digital, 5VDC  
(Output) Discrete 24VAC  
Digital, 5VDC  
LEGEND:  
CCN  
G
IAQ  
OAQ  
RAT  
---  
---  
---  
---  
---  
Carrier Comfort Network (communication bus)  
Thermostat Fan  
RH --- Relative Humidity  
W1 --- Thermostat Heat Stage 1  
W2 --- Thermostat Heat Stage 2  
Y1 --- Thermostat Cool Stage 1  
Y2 --- Thermostat Cool Stage 2  
Indoor Air Quality (CO )  
2
Outdoor Air Quality (CO )  
2
Return Air Temperature  
26  
TB3  
1
PL  
Space Sensors —  
SEN  
SEN  
J6-7  
The PremierLink controller is factory-shipped configured  
for Space Sensor Mode. A Carrier T-55 or T-56 space  
sensor must be used. T-55 space temperature sensor  
provides a signal of space temperature to the PremierLink  
control. T-56 provides same space temperature signal plus  
it allows for adjustment of space temperature setpoints  
from the face of the sensor by the occupants.  
PL  
TB3  
3
J6-6  
Jumper  
SET  
SET  
J6-5  
5
C10022  
Fig. 52 - PremierLink T-56 Sensor  
Connect Thermostat —  
A 7-wire thermostat connection requires a 24-v power  
source and a common connection. Use the R and C  
terminals on the CTB’s THERMOSTAT connection strip  
for these. Connect the thermostat’s Y1, Y2, W1, W2 and  
G terminals to PremierLink TB3 as shown in Fig. 53.  
1
2
4
5
6
3
RED(+)  
WHT(GND)  
CCN COM  
BLK(-)  
SEN  
SW1  
BRN (GND)  
BLU (SPT)  
SENSOR WIRING  
If the 48TC**16 unit is equipped with factory-installed  
smoke detector(s), disconnect the factory BLU lead at  
TB3-6 (Y2) before connecting the thermostat. Identify the  
BLU lead originating at CTB-DDC-1; disconnect at  
TB3-6 and tape off. Confirm that the second BLU lead at  
TB3-6 remains connected to PremierLink J4-8.  
SPACE  
THERMOSTAT  
CTB  
THERMOSTAT  
C08201  
Fig. 49 - T-55 Space Temperature Sensor Wiring  
R
TB3  
2
R
Connect T-55: See Fig. 49 for typical T-55 internal  
connections. Connect the T-55 SEN terminals to TB3  
terminals 1 and 3 (see Fig. 50).  
PL  
J4-12  
G
Y1  
Y2  
W1  
W2  
C
4
6
J4-10  
J4-8  
J4-6  
J4-4  
TB3  
1
PL  
SEN  
SEN  
J6-7  
8
J6-6  
3
10  
C
C10023  
Fig. 50 - PremierLink T-55 Sensor  
CTB  
THERMOSTAT  
Connect T-56: See Fig. 51 for T-56 internal connections.  
Install a jumper between SEN and SET terminals as  
illustrated. Connect T-56 terminals to TB3 terminals 1, 3  
and 5 (see Fig. 52).  
C10283  
Fig. 53 - Space Thermostat Connections  
If the 48TC**16 unit has an economizer system and  
free-cooling operation is required, a sensor representing  
Return Air Temperature must also be connected  
(field-supplied and installed). This sensor may be a T-55  
Space Sensor (see Fig. 49) installed in the space or in the  
return duct, or it may be sensor PNO 33ZCSENSAT,  
installed in the return duct. Connect this sensor to TB3-1  
and TB3-3 per Fig. 50.  
1
2
4
5
6
3
RED(+)  
WHT(GND)  
CCN COM  
BLK(-)  
SET  
SEN  
Configure the unit for Thermostat Mode —  
SW1  
BLK  
(T56)  
BRN (GND)  
BLU (SPT)  
SENSOR WIRING  
Connect to the CCN bus using a CCN service tool and  
navigate to PremierLink Configuration screen for Operating  
Mode. Default setting is Sensor Mode (value 1). Change the  
value to 0 to reconfigure the controller for Thermostat Mode.  
JUMPER  
TERMINALS  
AS SHOWN  
When the PremierLink is configured for Thermostat  
Mode, these functions are not available: Fire Shutdown  
(FSD), Remote Occupied (RMTOCC), Compressor Safety  
(CMPSAFE), Supply Fan Status (SFS), and Filter Pressure  
Switch (FILTER).  
Cool  
Warm  
C08202  
Fig. 51 - T-56 Internal Connections  
27  
To connect the sensor to the control, identify the positive  
(4 to 20 mA) and ground (SIG COM) terminals on the  
sensor. See Fig. 54. Connect the 4-20 mA terminal to  
terminal TB3-9 and connect the SIG COM terminal to  
terminal TB3-11. See Fig. 55.  
Economizer Controls  
Indoor Air Quality (CO2 sensor) —  
The indoor air quality sensor accessory monitors space  
carbon dioxide (CO2) levels. This information is used to  
monitor IAQ levels. Several types of sensors are available,  
for wall mounting in the space or in return duct, with and  
without LCD display, and in combination with space  
temperature sensors. Sensors use infrared technology to  
measure the levels of CO2 present in the space air.  
IAQ Sensor  
PL  
J5-5  
TB3  
9
SEN  
TB3  
11  
COM  
J5-3  
24 VAC  
C10284  
The CO2 sensors are all factory set for a range of 0 to  
2000 ppm and a linear mA output of 4 to 20. Refer to the  
instructions supplied with the CO2 sensor for electrical  
requirements and terminal locations. See Fig. 54 for  
typical CO2 sensor wiring schematic.  
Fig. 55 - Indoor CO2 Sensor (33ZCSENCO2)  
Connections  
Refer to Form 33CS-67SI, PremierLink Installation,  
Start-up, and Configuration Instructions, for detailed  
configuration information  
To accurately monitor the quality of the air in the  
conditioned air space, locate the sensor near a return-air  
grille (if present) so it senses the concentration of CO2  
leaving the space. The sensor should be mounted in a  
location to avoid direct breath contact.  
Outdoor Air Quality Sensor  
(PNO 33ZCSENCO2 plus weatherproof enclosure) —  
The outdoor air CO2 sensor is designed to monitor carbon  
dioxide (CO2) levels in the outside ventilation air and  
interface with the ventilation damper in an HVAC system.  
The OAQ sensor is packaged with an outdoor cover. See  
Fig. 56. The outdoor air CO2 sensor must be located in the  
economizer outside air hood.  
Do not mount the IAQ sensor in drafty areas such as near  
supply ducts, open windows, fans, or over heat sources.  
Allow at least 3 ft (0.9 m) between the sensor and any  
corner. Avoid mounting the sensor where it is influenced  
by the supply air; the sensor gives inaccurate readings if  
the supply air is blown directly onto the sensor or if the  
supply air does not have a chance to mix with the room air  
before it is drawn into the return airstream.  
+ 0-10VDC  
-
SIG COM  
4-20mA  
+
ALARM  
NC  
COM RELAY  
}
NO CONTACTS  
COVER REMOVED  
SIDE VIEW  
24 VAC  
OR  
24 VDC  
H G  
C07135  
+
-
Fig. 56 - Outdoor Air Quality Sensor Cover  
2 1  
J3  
5 4 3 2 1  
8 7 6  
J4  
Wiring the Outdoor Air CO2 Sensor: A dedicated  
power supply is required for this sensor. A two-wire cable  
is required to wire the dedicated power supply for the  
sensor. The two wires should be connected to the power  
supply and terminals 1 and 2.  
C08635  
Fig. 54 - Indoor/Outdoor Air Quality (CO2) Sensor  
(33ZCSENCO2) - Typical Wiring Diagram  
To connect the sensor to the control, identify the positive  
(4 to 20 mA) and ground (SIG COM) terminals on the  
OAQ sensor. See Fig. 54. Connect the 4 to 20 mA  
terminal to the TB3-13 terminal of the 48TC**16.  
Connect the SIG COM terminal to the TB3-11 terminal of  
the 48TC**16. See Fig. 57.  
Wiring the Indoor Air Quality Sensor: For each sensor,  
use two 2-conductor 18 AWG (American Wire Gage)  
twisted-pair cables (unshielded) to connect the separate  
isolated 24 vac power source to the sensor and to connect  
the sensor to the control board terminals.  
28  
IAQ Sensor  
24 VAC  
PL  
J5-2  
TB3  
13  
SEN  
TB3  
11  
MOUNTING  
HOLES  
COM  
J5-3  
WIRING  
OPENING  
Io  
Vin Gnd  
Vo  
C10285  
Fig. 57 - Outdoor CO2 Sensor Connections  
Space Relative Humidity Sensor or Humidistat  
Connections —  
3 SW2  
6
5
4
1
2
Space Relative Humidity Sensor connections: The  
accessory space relative humidity sensor (33ZCSENSRH-01)  
is installed on an interior wall to measure the relative  
humidity of the air within the occupied space.  
O N  
The use of a standard 2 X 4 inch electrical box to  
accommodate the wiring is recommended for installation.  
The sensor can be mounted directly on the wall, if  
acceptable by local codes.  
Fig. 58 - Space Relative Humidity Sensor InstallaCti1o10n84  
TB3-7  
!
CAUTION  
TB3-13  
UNIT DAMAGE HAZARD  
Failure to follow this caution may result in  
permanent damage to the sensor.  
DO NOT clean or touch the sensing element with  
chemical solvents as they can permanently damage the  
sensor.  
Io Vin Gnd Vo  
!
CAUTION  
UNIT PERFORMANCE HAZARD  
Failure to follow this caution will result in inaccurate  
sensor readings.  
C11085  
DO NOT mount the sensor in drafty areas such as near  
heating or air-conditioning ducts, open windows, fans,  
or over heat sources such as baseboard heaters,  
radiators, or wall-mounted dimmers. Sensors mounted  
in those areas will produce inaccurate readings.  
Fig. 59 - Space Relative Humidity Sensor Connection  
The power for the sensor is provided by the PremierLink  
control on terminal J5-4 (+33 to +35vdc).  
To wire the sensor:  
1. At the sensor, remove 4 inches of the jacket from the  
If the sensor is installed directly on a wall service, install the  
humidity sensor using 2 screws and 2 hollow wall anchors  
(field supplied). Do not over tighten screws. See Fig. 58.  
The sensor must be mounted vertically on the wall. The  
Carrier logo should be orientated correctly when the  
sensor is properly mounted.  
1
cable. Strip /4 inch of insulation from each conduct-  
or. Route the cable through the wire clearance open-  
ing in the center of the sensor. See Fig. 58.  
2. Connect a field-supplied BLACK wire to the sensor  
screw terminal marked Vin.  
3. Connect a field-supplied RED wire into the sensor  
screw terminal marked Io.  
4. Connect the field-supplied RED wire from the sensor  
to TB3-13.  
5. Connect the field-supplied BLACK wire from the  
sensor to TB3-7.  
Avoid corner locations. Allow at least 4 ft between the  
sensor and any corner. Airflow near corners tends to be  
reduced, resulting in erratic sensor readings. The sensor  
should be vertically mounted approximately 5 ft up from  
the floor, beside the space temperature sensor.  
For wiring distances up to 500 feet, use a 3-conductor, 18  
or 20 AWG cable. ACCN communication cable can be  
used, although the shield is not required. The shield must  
be removed from the sensor end of the cable if this cable  
is used. See Fig. 59 for wiring details.  
Humidistat connections: A humidistat can not be directly  
connected to the PremierLink controller. Follow the  
instructions on pages 20 & 21 to connect a humidistat or a  
thermostat as an electromechanical device.  
29  
Smoke Detector/Fire Shutdown (FSD) —  
Connect one side of the switch’s NO contact set to CTB’s  
THERMOSTAT-R terminal. Connect the other side of the  
NO contact set to TB3-8. Setpoint for Supply Fan Status  
is set at the switch. See Fig. 61.  
This function is available only when PremierLink is  
configured for (Space) Sensor Mode. The unit is  
factory-wired for PremierLink FSD operation when  
PremierLink is factory-installed.  
Fan (Pressure) Switch (NO, close on rise in pressure)  
CTB  
On 48TC**16 units equipped with factory-installed  
Smoke Detector(s), the smoke detector controller  
implements the unit shutdown through its NC contact set  
connected to the unit’s CTB input. The FSD function is  
initiated via the smoke detector’s Alarm NO contact set.  
The PremierLink communicates the smoke detector’s  
tripped status to the CCN building control. See Fig. 46,  
the PremierLink wiring schematic.  
Thermostat  
R
TB3  
8
PL  
J4-6  
C10287  
Fig. 61 - PremierLink Wiring Fan Pressure Switch  
Connection  
Filter Status Switch —  
Remote Occupied Switch —  
This function is available only when PremierLink is  
configured for (Space) Sensor Mode.  
The PremierLink control permits a remote timeclock to  
override the control’s on-board occupancy schedule and  
place the unit into Occupied mode. This function may also  
provide a “Door Switch” time delay function that will  
terminate cooling and heating functions after a 2-20 minute  
delay.  
PremierLink control can monitor return filter status in two  
ways: By monitoring a field-supplied/installed filter  
pressure switch or via supply fan runtime hours.  
Using switch input: Install the dirty filter pressure switch  
according to switch manufacturer’s instructions, to  
measure pressure drop across the unit’s return filters.  
Connect one side of the switch’s NO contact set to CTB’s  
THERMOSTAT-R terminal. Connect the other side of the  
NO contact set to TB3-10. Setpoint for Dirty Filter is set  
at the switch. See Fig. 60.  
Connect one side of the NO contact set on the timeclock  
to CTB’s THERMOSTAT-R terminal. Connect the other  
side of the timeclock contact to the unit’s TB3-2 terminal.  
See Fig. 62.  
LCTB  
Remote Occupied  
Thermostat  
R
Filter Switch (NO, close on rising pressure (high drop))  
CTB  
Time Clock  
TB3  
2
PL  
J4-12  
Thermostat  
R
C10288  
TB3  
10  
PL  
J4-4  
Fig. 62 - PremierLink Wiring Remote Occupied  
Refer to Form 33CS-67SI for additional information on  
configuring the PremierLink control for Door Switch  
timer function.  
C10286  
Fig. 60 - PremierLink Filter Switch Connection  
When the filter switch’s NO contact set closes as filter  
pressure drop increases (indicating dirt-laden filters), the  
input signal to PremierLink causes the filter status point to  
read “DIRTY”.  
Power Exhaust (output) —  
Connect the accessory Power Exhaust contactor coils(s)  
per Fig. 63.  
Power Exhaust  
Using Filter Timer Hours: Refer to Form 33CS-67SI for  
instructions on using the PremierLink Configuration  
screens and on unit alarm sequence.  
TB3  
15  
PL  
J8-3  
PEC  
GRA  
TAN  
CTB  
Supply Fan Status Switch —  
THERMOSTAT  
C
The PremierLink control can monitor supply fan operation  
through a field-supplied/installed differential pressure  
switch. This sequence will prevent (or interrupt) operation  
of unit cooling, heating and economizer functions until  
the pressure switch contacts are closed indicating proper  
supply fan operation.  
C10289  
Fig. 63 - PremierLink Power Exhaust Output  
Connection  
Install the differential pressure switch in the supply fan  
section according to switch manufacturer’s instructions.  
Arrange the switch contact to be open on no flow and to  
close as pressure rises indicating fan operation.  
30  
CCN Communication Bus —  
The communication bus shields must be tied together at  
each system element. If the communication bus is entirely  
within one building, the resulting continuous shield must  
be connected to ground at only one single point. If the  
communication bus cable exits from one building and  
enters another building, the shields must be connected to  
the grounds at a lightning suppressor in each building (one  
point only).  
The PremierLink controller connects to the bus in a daisy  
chain arrangement. Negative pins on each component  
must be connected to respective negative pins, and  
likewise, positive pins on each component must be  
connected to respective positive pins. The controller  
signal pins must be wired to the signal ground pins.  
Wiring connections for CCN must be made at the 3-pin  
plug.  
Connecting CCN Bus:  
NOTE: When connecting the communication bus cable,  
At any baud (9600, 19200, 38400 baud), the number of  
controllers is limited to 239 devices maximum. Bus length  
may not exceed 4000 ft, with no more than 60 total  
devices on any 1000-ft section. Optically isolated RS-485  
repeaters are required every 1000 ft.  
a
color code system for the entire network is  
recommended to simplify installation and checkout. See  
Table 7 for the recommended color code.  
Table 7 – Color Code Recommendations  
NOTE: Carrier device default is 9600 band.  
CCN BUS WIRE  
COLOR  
CCN PLUG PIN  
NUMBER  
SIGNAL TYPE  
Communications Bus Wire Specifications: The CCN  
Communication Bus wiring is field-supplied and  
field-installed. It consists of shielded 3-conductor cable  
with drain (ground) wire. The cable selected must be  
identical to the CCN Communication Bus wire used for  
the entire network.  
+
Ground  
---  
Red  
White  
Black  
1
2
3
See Table 6 for recommended cable.  
Connect the CCN (+) lead (typically RED) to the unit’s  
TB3-12 terminal. Connect the CCN (ground) lead  
(typically WHT) to the unit’s TB3-14 terminal. Connect  
the CCN (-) lead (typically BLK) to the unit’s TB3-16  
terminal. See Fig. 64.  
Table 6 – Recommended Cables  
MANUFACTURER  
Alpha  
CABLE PART NO.  
2413 or 5463  
A22503  
CCN Bus  
American  
Belden  
PL  
J2-1  
TB3  
12  
8772  
+ (RED)  
GND (WHT)  
– (BLK)  
Columbia  
02525  
TB3  
14  
J2-2  
J2-3  
NOTE: Conductors and drain wire must be at least 20  
AWG, stranded, and tinned copper. Individual conductors  
must be insulated with PVC, PVC/nylon, vinyl, Teflon, or  
polyethylene. An aluminum/polyester 100% foil shield  
and an outer jacket of PVC, PVC/nylon, chrome vinyl, or  
Teflon with a minimum operating temperature range of  
- 2 0 _C to 60_C is required. Do not run communication  
wire in the same conduit as or next to any AC voltage  
wiring.  
TB3  
16  
C10290  
Fig. 64 - PremierLink CCN Bus Connections  
31  
The RTU Open controller is an integrated component of  
the Carrier rooftop unit. Its internal application  
programming provides optimum performance and energy  
efficiency. RTU Open enables the unit to run in 100%  
stand-alone control mode, Carrier’s I-Vu Open network,  
or a Third Party Building Automation System (BAS).  
On-board DIP switches allow you to select your protocol  
(and baud rate) of choice among the four most popular  
protocols in use today: BACnet, Modbus, Johnson N2 and  
LonWorks. (See Fig. 65.)  
RTU Open Control System  
The RTU Open control is factory-mounted in the  
48TC**16 unit’s main control box, to the left of the CTB.  
See Fig. 66. Factory wiring is completed through  
harnesses connected to the CTB. Field connections for  
RTU Open sensors will be made at the Phoenix connectors  
on the RTU Open board. The factory-installed RTU Open  
control includes the supply-air temperature (SAT) sensor.  
The outdoor air temperature (OAT) sensor is included in  
the FIOP/accessory EconoMi$er2 package.  
Refer to Table 8, RTU Open Controller Inputs and Outputs  
for locations of all connections to the RTU Open board.  
C10811  
Fig. 65 - RTU Open Multi-Protocol Control Board  
C10810  
Fig. 66 - 48TC**16 Control Box Component Locations  
32  
C11204  
Fig. 67 - RTU Open System Control Wiring Diagram  
33  
C11205  
Fig. 68 - RTU Open System Control Wiring Diagram with Humidi-MiZerR  
34  
Table 8 – RTU Open Controller Inputs and Outputs  
BACnet OBJECT  
TYPE OF I/O  
NAME  
CONNECTION PIN  
NUMBER(S)  
POINT NAME  
DEDICATED INPUTS  
Space Temp / Zone Temp  
Supply Air Temperature  
Outdoor Air Temperature  
Space Temperature Offset Pot  
Safety Chain Feedback  
Compressor Safety Status  
Fire Shutdown Status  
zone_temp  
sa_temp  
oa_temp  
stpt_adj_offset  
safety_status  
comp_status  
firedown_status  
enthalpy_status  
humstat_status  
AI (10K Thermistor)  
AI (10K Thermistor)  
AI (10K Thermistor)  
AI (100K Potentiometer)  
DI (24 VAC)  
J 2 0 --- 1 , 2  
J 2 --- 1 , 2  
J 2 --- 3 , 4  
J 2 0 --- 3  
J 1 --- 9  
J 1 --- 2  
J 1 --- 1 0  
J 2 --- 6  
DI (24 VAC)  
DI (24 VAC)  
DI (24 VAC)  
DI (24 VAC)  
Enthalpy Status  
Humidistat Input Status  
J 5 --- 7  
CONFIGURABLE INPUTS  
Indoor Air CO2  
iaq  
oaq  
space_rh  
A I ( 4 --- 2 0 m a )  
A I ( 4 --- 2 0 m a )  
A I ( 4 --- 2 0 m a )  
DI (24 VAC)  
DI (24 VAC)  
DI (24 VAC)  
DI (24 VAC)  
Outdoor Air CO2  
Space Relative Humidity  
Supply Fan Status*  
Filter Status*  
Door Contact Input*  
Occupancy Contact*  
J 4 --- 2 o r J 4 --- 5  
sfan_status  
filter_status  
door_contact_status  
occ_contact_status  
J 5 --- 1 o r J 5 --- 3 o r  
J5 5 or J5---7  
OUTPUTS  
Economizer Output  
econ_output  
sfan  
A O ( 4 --- 2 0 m a )  
J 2 --- 5  
J 1 --- 4  
J 1 --- 8  
J 1 --- 7  
J 1 --- 6  
J 1 --- 5  
J 1 1 --- 3  
J 1 1 --- 7 , 8  
Supply Fan Relay State  
Compressor 1 Relay State  
Compressor 2 Relay State  
Heat Stage 1 Relay State  
Heat Stage 2 Relay State  
Power Exhaust Relay State  
Dehumidification Relay State  
DO Relay (24VAC , 1A)  
DO Relay (24VAC , 1A)  
DO Relay (24VAC , 1A)  
DO Relay (24VAC , 1A)  
DO Relay (24VAC , 1A)  
DO Relay (24VAC , 1A)  
DO Relay (24VAC, 1A)  
comp_1  
comp_2  
heat_1  
heat_2  
pexh  
dehum  
LEGEND  
AI --- An al og In pu t  
AO --- An al og Ou tpu t  
DI --- D iscr ete In pu t  
DO --- Discrete Output  
*
These inputs (if installed) take the place of the default input on the specific channel according to schematic.  
Par al l el pin s J 5 --- 1 = J 2 --- 6, J 5 --- 3 = J 1 --- 10, J 5 --- 5 = J 1 --- 2 ar e u sed f or f iel d --- in stal l ation .  
The RTU Open controller requires the use of a Carrier  
space sensor. A standard thermostat cannot be used with  
the RTU Open system.  
EconoMi$er2 —  
The RTU Open control is used with EconoMi$er2 (option  
or accessory) for outdoor air management. The damper  
position is controlled directly by the RTU Open control;  
EconoMi$er2 has no internal logic device.  
Supply Air Temperature (SAT) Sensor —  
On FIOP-equipped 48TC**16 unit, the unit is supplied with  
a supply-air temperature (SAT) sensor (33ZCSENSAT). This  
sensor is a tubular probe type, approx 6-inches (12.7 mm) in  
length. It is a nominal 10-k ohm thermistor.  
Outdoor air management functions can be enhanced with  
field-installation of these accessory control devices:  
Enthalpy control (outdoor air or differential sensors)  
Space CO2 sensor  
Outdoor air CO2 sensor  
The SAT is factory-wired. The SAT probe is wire-tied to  
the supply-air opening (on the horizontal opening end) in  
its shipping position. Remove the sensor for installation.  
Re-position the sensor in the flange of the supply-air  
opening or in the supply air duct (as required by local  
Field Connections  
1
codes). Drill or punch a /2 -in. hole in the flange or duct.  
Field connections for accessory sensors and input devices  
are made the RTU Open, at plugs J1, J2, J4, J5, J11 and  
J20. All field control wiring that connects to the RTU  
Open must be routed as shown in Fig. 39. This routing  
provides the UL required clearance between high- and  
low-voltage wiring. Connect to the wires to the  
removable Phoenix connectors and then reconnect the  
connectors to the board.  
Use two field-supplied, self-drilling screws to secure the  
sensor probe in a horizontal orientation. See Fig. 48.  
Outdoor Air Temperature (OAT) Sensor —  
The OAT is factory-mounted in the EconoMi$er2 (FIOP  
or accessory). It is a nominal 10k ohm thermistor attached  
to an eyelet mounting ring.  
35  
Space Temperature (SPT) Sensors —  
Connect T  
                                                                                                                             
-59: The T-59 space sensor requires a  
                                                                                                                                                
separate, isolated power supply of 24 VAC. See Fig. 71  
for internal connections at the T-59. Connect the SEN  
terminal (BLU) to RTU Open J20-1. Connect the COM  
terminal (BRN) to J20-2. Connect the SET terminal (STO  
or BLK) to J20-3.  
There are two types of SPT sensors available from Carrier,  
resistive input non-communicating (T55, T56, and T59)  
and Rnet communicating (SPS, SPPL, SPP, and SPPF)  
sensors. Each type has a variety of options consisting of:  
timed override button, set point adjustment, a LCD  
screen, and communication tie in. Space temperature can  
be also be written to from a building network or zoning  
system. However, it is still recommended that return air  
duct sensor be installed to allow stand-alone operation for  
back-up. Refer to the configuration section for details on  
controller configurations associated with space sensors.  
BLK (STO)  
J20-3  
BRN (COM)  
SENSOR  
J20-2  
WIRING  
BLU (SPT)  
J20-1  
Field connections to T-55, T-56 and T-59 are provided as  
examples.  
OR  
SET SEN  
S 33ZCT55SPT, space temperature sensor with override  
button (T-55)  
S 33ZCT56SPT, space temperature sensor with override  
OPB COM- PWR+  
button and setpoint adjustment (T-56)  
S 33ZCT59SPT, space temperature sensor with LCD  
(liquid crystal display) screen, override button, and  
setpoint adjustment (T-59)  
POWER  
WIRING  
24 VAC  
NOTE: Must use a separate isolated transformer.  
Use 20 gauge wire to connect the sensor to the controller.  
The wire is suitable for distances of up to 500 ft. Use a  
three-conductor shielded cable for the sensor and setpoint  
adjustment connections. If the setpoint adjustment  
(slidebar) is not required, then an unshielded, 18 or 20  
gauge, two-conductor, twisted pair cable may be used.  
C10291  
Fig. 71 - Space Temperature Sensor Typical Wiring  
(33ZCT59SPT)  
Indoor Air Quality (CO2 sensor) —  
Connect T-55: See Fig. 49 for typical T-55 internal  
connections. Connect the T-55 SEN terminals to RTU Open  
J20-1 and J20-2. See Fig. 69.  
The indoor air quality sensor accessory monitors space  
carbon dioxide (CO2) levels. This information is used to  
monitor IAQ levels. Several types of sensors are available,  
for wall mounting in the space or in return duct, with and  
without LCD display, and in combination with space  
temperature sensors. Sensors use infrared technology to  
measure the levels of CO2 present in the space air.  
J20-1  
J20-2  
SEN  
SEN  
The CO2 sensors are all factory set for a range of 0 to  
2000 ppm and a linear mA output of 4 to 20. Refer to the  
instructions supplied with the CO2 sensor for electrical  
requirements and terminal locations. See Fig. 54 for  
typical CO2 sensor wiring schematic.  
C08460  
Fig. 69 - RTU Open T-55 Sensor Connections  
Connect T-56: See Fig. 51 for T-56 internal connections.  
Install a jumper between SEN and SET terminals as  
illustrated. Connect T-56 terminals to RTU Open J20-1,  
J20-2 and J20-3 per Fig. 70.  
To accurately monitor the quality of the air in the  
conditioned air space, locate the sensor near a return-air  
grille (if present) so it senses the concentration of CO2  
leaving the space. The sensor should be mounted in a  
location to avoid direct breath contact.  
SEN  
SEN  
J20-1  
J20-2  
Do not mount the IAQ sensor in drafty areas such as near  
supply ducts, open windows, fans, or over heat sources.  
Allow at least 3 ft (0.9 m) between the sensor and any  
corner. Avoid mounting the sensor where it is influenced  
by the supply air; the sensor gives inaccurate readings if  
the supply air is blown directly onto the sensor or if the  
supply air does not have a chance to mix with the room air  
before it is drawn into the return airstream.  
Jumper  
SET  
SET  
J20-3  
C08461  
Fig. 70 - RTU Open T-56 Sensor Connections  
36  
Wiring the Indoor Air Quality Sensor: For each sensor,  
use two 2-conductor 18 AWG (American Wire Gage)  
twisted-pair cables (unshielded) to connect the separate  
isolated 24 vac power source to the sensor and to connect  
the sensor to the control board terminals.  
Space Relative Humidity Sensor or Humidistat —  
Humidi-MiZerR Control Wiring: In units equipped  
with the Humidi-MiZer option there are two pink (PNK)  
wires loose in the control box used to control the  
dehumidification function of the unit. These pink wires  
are meant to be tied to a space humidistat or thermidistat  
on an electromechanical unit. On RTU Open equipped  
units these pink wires must be connected to J11-7 & 8 to  
allow the Open board to operate the dehumidification  
function for the unit. Disconnect the J11 Phoenix style  
connector from the board and use the plug screws to  
secure the pink wires in pins 7 and 8, reconnect the plug  
to the board at J11.  
To connect the sensor to the control, identify the positive  
(4 to 20 mA) and ground (SIG COM) terminals on the  
sensor. See Fig. 54. Connect the 4-20 mA terminal to  
RTU Open J4-2 and connect the SIG COM terminal to  
RTU Open J4-3. See Fig. 72.  
IAQ Sensor  
Relative Humidity Sensors (Space or Duct Mounted):  
The accessory space humidity sensor (33ZCSENSRH-01)  
or duct humidity sensor (33ZCSENDRH-01) is used to  
measure the relative humidity of air within the space or  
return air duct. The RH reading is used to control the  
Humidi-MiZer option of the rooftop unit. For wiring  
distances up to 500 ft (152 m), use a 3-conductor, 18 or  
20 AWG shielded cable. The shield must be removed  
from the sensor end of the cable and grounded at the unit  
end. The current loop power for sensor is provided by the  
RTU Open controller as 24vdc. Refer to the instructions  
supplied with the RH sensor for the electrical  
requirements and terminal locations. RTU Open  
configurations must be changed after adding an RH  
sensor. See Fig. 74 and 75 for typical RH sensor wiring.  
4-20mA  
J4-2  
J4-3  
C10738  
SIG COM  
24 VAC  
Fig. 72 - RTU Open / Indoor CO2 Sensor  
(33ZCSENCO2) Connections  
Outdoor Air Quality Sensor  
(PNO 33ZCSENCO2 plus weatherproof enclosure) —  
The outdoor air CO2 sensor is designed to monitor carbon  
dioxide (CO2) levels in the outside ventilation air and  
interface with the ventilation damper in an HVAC system.  
The OAQ sensor is packaged with an outdoor cover. See  
Fig. 56. The outdoor air CO2 sensor must be located in the  
economizer outside air hood.  
S J4-1 or J4-4 = 24vdc loop power  
S J4-2 or J4-5 = 4-20mA signal input  
NOTE: The factory default for dehumidification control  
is normally open humidistat.  
Wiring the Outdoor Air CO2 Sensor: A dedicated  
power supply is required for this sensor. A two-wire cable  
is required to wire the dedicated power supply for the  
sensor. The two wires should be connected to the power  
supply and terminals 1 and 2.  
MOUNTING  
HOLES  
To connect the sensor to the control, identify the positive  
(4 to 20 mA) and ground (SIG COM) terminals on the  
OAQ sensor. See Fig. 54. Connect the 4 to 20 mA  
terminal to RTU Open J4-5. Connect the SIG COM  
terminal to RTU Open J4-6. See Fig. 73.  
WIRING  
Io  
Gnd  
Vin  
Vo  
OPENING  
OAQ Sensor/RH Sensor  
4-20mA  
J4-5  
J4-6  
C10739  
3 SW2  
6
5
4
1
2
O N  
SIG COM  
24 VAC  
Fig. 73 - RTU Open / Outdoor CO2 Sensor  
(33ZCSENCO2) Connections  
Vin - J4-1 or J4-4 24Vdc  
Io - J4-2 or J4-5 -20mA output  
C11087  
Fig. 74 - Space Relative Humidity Sensor Typical Wiring  
37  
J4-1 or J4-4 + 24 VDC Supply Voltage  
J4-2 or J4-5 (-) 4 to 20 mA Current Loop Output  
to RTU-OPEN  
Relative Humidity Sensor  
(Polarized Male Connector)  
SPAN  
ZERO  
4-20 VAC GND 0-5V  
mA or  
VDC  
or  
0-10V  
C10839  
Fig. 75 - Duct Relative Humidity Sensor Typical Wiring  
Humidistat: The accessory humidistat provides the RTU  
Open insight to the relative humidity in the space. The  
humidistat reads the RH level in the space and compares it  
to its setpoint to operate a dry contact. The humidistat is a  
dedicated input on the configurable input 9 and tells the  
RTU Open when the RH level is HIGH or LOW. The  
normal condition for humidity is LOW. A normally open  
humidistat is the factory default control for the  
Humidi-MiZerR option.  
Fan Status: The fan status accessory is a field-installed  
accessory. This accessory detects when the indoor fan is  
blowing air. When installing this accessory, the unit must  
be  
configured  
for  
fan  
status  
by  
setting  
MENUConfigInputsinput 3, 5, 8, or 9 to Fan  
Status and normally open (N/O) or normally closed (N/C).  
Input 8 or 9 is recommended for easy of installation. Refer  
to Fig. 65 and Fig. 67 or Fig. 68 for wire terminations at  
J5.  
To wire in the field:  
S J5-8 = 24 VAC source for dry contact  
Remote Occupancy: The remote occupancy accessory is  
a field-installed accessory. This accessory overrides the  
unoccupied mode and puts the unit in occupied mode.  
When installing this accessory, the unit must be  
S J5-7 = Signal input  
configured for  
remote occupancy by setting  
Smoke Detector/Fire Shutdown (FSD) —  
MENUConfigInputsinput 3, 5, 8, or 9 to Remote  
Occupancy and normally open (N/O) or normally closed  
(N/C).  
Also set MENUSchedulesoccupancy source to DI  
on/off. Input 8 or 9 is recommended for easy of  
installation. Refer to Fig. 65 and Table 8 for wire  
terminations at J5.  
On 48TC**16 units equipped with factory-installed  
Smoke Detector(s), the smoke detector controller  
implements the unit shutdown through its NC contact set  
connected to the unit’s CTB input. The FSD function is  
initiated via the smoke detector’s Alarm NO contact set.  
The RTU Open controller communicates the smoke  
detector’s tripped status to the BAS building control. See  
Fig. 67, the RTU Open System Control Wiring Diagram.  
Power Exhaust (output): The relay used by the RTU  
Open board to control power exhaust is a dry contact  
which means it does not have 24vac. This 24vac must be  
connected to the relay to allow it to operate the power  
exhaust relay in the PE accessory. A 24vac source must be  
provided to J11-2 on the RTU Open control board. This  
can be provided by the unit’s transformer from various  
sources. The “R” terminal on the unit’s low voltage  
terminal board (LVTB) is a logical source. Refer to Fig.  
65 and Fig. 67 or Fig. 68 for wire terminations at J11.  
The  
Fire  
Shutdown  
Switch  
configuration,  
MENUConfigInputsinput 5, identifies the normally  
open status of this input when there is no fire alarm.  
Connecting Discrete Inputs —  
Filter Status: The filter status accessory is a field-installed  
accessory. This accessory detects plugged filters. When  
installing this accessory, the unit must be configured for  
filter status by setting MENUConfigInputsinput 3, 5,  
8, or 9 to Filter Status and normally open (N/O) or normally  
closed (N/C). Input 8 or 9 is recommended for easy of  
installation. Refer to Fig. 65 and Fig. 67 or Fig. 68 for wire  
terminations at J5.  
38  
The RTU Open can be set to communicate on four  
different protocols: BACnet, Modbus, N2, and LonWorks.  
Switch 3 (SW3) on the board is used to set protocol and  
baud rate. Switches 1 and 2 (SW1 and SW2) are used to  
set the board’s network address. See Fig. 76 and 77 for  
protocol switch settings and address switches. The 3rd  
party connection to the RTU Open is through plug J19.  
See Fig. 78 for wiring.  
NOTE: Power must be cycled after changing the SW1-3  
switch settings.  
Refer to the RTU Open Controller Integration Guide  
(Catalog No. 11-808-428-01) for more detailed information  
on protocols, 3rd party wiring, and networking.  
Communication Wiring -- Protocols  
General —  
Protocols are the communication languages spoken by  
control devices. The main purpose of a protocol is to  
communicate information in the most efficient method  
possible. Different protocols exist to provide different  
kinds of information for different applications. In the BAS  
application, many different protocols are used, depending  
on manufacturer. Protocols do not change the function of  
a controller; just make the front end user different.  
SW3 Protocol Selection  
DS6 DS5  
OFF OFF  
PROTOCOL  
DS8  
DS7  
DS4  
DS3  
DS2  
DS1  
BACnet MS/TP  
(Master)  
Unused  
OFF  
ON  
OFF  
Select Baud Select Baud  
Select Baud Select Baud  
Modbus  
(Slave)  
Unused  
OFF  
OFF  
ON  
ON  
OFF  
N2  
Unused  
Unused  
OFF  
ON  
OFF  
ON  
OFF  
OFF  
ON  
ON  
ON  
OFF  
OFF  
OFF  
OFF  
(Slave)  
LonWorks  
OFF  
NOTE:  
DS = Dip Switch  
BACnet MS/TP SW3 example shown  
Baud Rate Selections  
BAUD RATE  
9600  
DS2  
OFF  
ON  
DS1  
OFF  
OFF  
ON  
19,200  
38,400  
OFF  
ON  
76,800  
ON  
C07166  
Fig. 76 - RTU Open SW3 Dip Switch Settings  
C10815  
Fig. 77 - RTU Open Address Switches  
C10816  
Fig. 78 - Network Wiring  
39  
Local Access —  
Virtual BACview: Virtual BACview is a freeware computer  
program that functions as the BACview6 Handheld. The  
USB Link interface (USB-L) is required to connect a  
computer to the RTU Open board. The link cable connects  
a USB port to the J12 local access port. This program  
functions and operates identically to the handheld.  
6
6
BACview Handheld: The BACview is a keypad/display  
interface used to connect to the RTU Open to access the  
control information, read sensor values, and test the RTU,  
see Fig. 79. This is an accessory interface that does not  
come with the RTU Open controller and can only be used  
at the unit. Connect the BACview6 to the RTU Open’s J12  
local access port. There are 2 password protected levels in  
the display (User and Admin). The user password is  
defaulted to 0000 but can be changed. The Admin  
password is 1111 and cannot be changed. There is a 10  
minute auto logout if a screen is idle. See Form  
48-50HCTQ-01T, Appendix A for navigation and screen  
content.  
RTU Open Troubleshooting —  
Communication LEDs: The LEDs indicate if the  
controller is speaking to the devices on the network. The  
LEDs should reflect communication traffic based on the  
baud rate set. The higher the baud rate the more solid the  
LEDs will appear. See Table 9.  
Access Port  
P1 P1  
Protocol Selector  
RTU Open  
J12  
P5 P5  
Cable  
BACview6 Local Access Cable  
C10812  
Fig. 79 - BACview6 Handheld Connections  
40  
Table 9 – LEDs  
The LEDs on the RTU Open Control Board (see Fig. 65) show the status of certain functions:  
If this LED is on...  
Status is...  
Power  
Rx  
Tx  
RTU Open has power  
RTU Open is receiving data from the network segment  
RTU Open is transmitting data over the network segment  
The digital output is active  
DO#  
The Run and Error LEDs indicate control module and network status  
If Run LED shows...  
And Error LED shows...  
Status is...  
2 flashes per second  
Off  
Normal  
2 flashes,  
2 flashes per second  
2 flashes per second  
2 flashes per second  
2 flashes per second  
Five minute auto---restart delay after system error  
Control module has just been formatted  
alternating with Run LED  
3 flashes,  
then off  
4 flashes,  
then pause  
Two or more devices on this network have the  
same ARC156 network address  
Exec halted after frequent system errors or  
control programs halted  
On  
5 flashes per second  
5 flashes per second  
On  
Off  
Exec start---up aborted, Boot is running  
Firmware transfer in progress, Boot is running  
7 flashes per second, alternating with  
7 flashes per second  
14 flashes per second  
Ten second recovery period after brownout  
Run LED  
14 flashes per second,  
alternating with Run LED  
Brownout  
Failure. Try the following solutions:  
S
S
S
S
Turn RTU Open off, then on.  
Format RTU Open.  
Download memory to RTU Open.  
Replace RTU Open.  
On  
On  
NOTE:  
Refer to Catalog No. 48-50HCTQ-01T for  
Differential Enthalpy Control —  
complete configuration of RTU Open, operating sequences  
and troubleshooting information. Refer to RTU Open  
Controller Integration Guide (Catalog No. 11-808-428-01)  
for details on configuration and troubleshooting of connected  
networks. Have a copy of these manuals available at unit  
start-up.  
Differential enthalpy control is provided by sensing and  
comparing the outside air and return air enthalpy conditions.  
Install the outdoor air enthalpy control as described above.  
Add and install a return air enthalpy sensor.  
Return Air Enthalpy Sensor —  
Mount the return-air enthalpy sensor (33CSENTSEN) in the  
return-air section of the economizer. The return air sensor is  
wired to the enthalpy controller (33CSENTHSW). See  
Fig. 80.  
Outdoor Air Enthalpy Control  
(PNO 33CSENTHSW)  
The enthalpy control (33CSENTHSW) is available as a  
field-installed accessory to be used with the EconoMi$er2  
damper system. The outdoor air enthalpy sensor is part of  
the enthalpy control. (The separate field-installed  
accessory return air enthalpy sensor (33CSENTSEN) is  
required for differential enthalpy control. See Fig. 80.)  
24V  
RED  
PL6-1 (24-V)  
PL6-4 (COM)  
4-20  
Main  
BLK  
GND  
LOW  
+ VDC  
Out  
CTB ECON  
(P’LINK: to J4-2) or  
(RTU Open: to J2-6)  
GRA  
7
Outside Air  
Enthalpy Switch  
Locate the enthalpy control in the economizer next to the  
Actuator Motor. Locate two GRA leads in the factory  
harness and connect the gray lead labeled “ESL” to the  
terminal labeled “LOW”. See Fig. 80. Connect the  
enthalpy control power input terminals to economizer  
actuator power leads RED (connect to 24V) and BLK  
(connect to GND).  
+ 24-36  
Return Air  
Enthalpy  
Sensor  
VDC In  
4-20 Main  
Out  
C11161  
Fig. 80 - Outside and Return Air Enthalpy Sensor  
Wiring  
The outdoor enthalpy changeover setpoint is set at the  
enthalpy controller.  
41  
To wire the return air enthalpy sensor, perform the  
following:  
1. Use a 2-conductor, 18 or 20 AWG, twisted pair cable  
to connect the return air enthalpy sensor to the en-  
thalpy controller.  
2. Connect the field-supplied RED wire to (+) spade con-  
nector on the return air enthalpy sensor and the (+) ter-  
minal on the enthalpy controller. Connect the BLK wire  
to (-) spade connector on the return air enthalpy sensor  
and the (-) terminal on the enthalpy controller.  
Duct smoke sensor  
controller  
Conduit nuts  
(supplied by installer)  
Conduit support plate  
Smoke Detectors  
Terminal block cover  
Cover gasket  
(ordering option)  
Controller housing  
and electronics  
Controller cover  
Smoke detectors are available as factory-installed options on  
48TC**16 units. Smoke detectors may be specified for  
Supply Air only or for Return Air without or with  
economizer or in combination of Supply Air and Return Air.  
Return Air smoke detectors are arranged for vertical return  
configurations only. All components necessary for operation  
are factory-provided and mounted. The unit is  
factory-configured for immediate smoke detector shutdown  
operation; additional wiring or modifications to unit terminal  
board may be necessary to complete the unit and smoke  
detector configuration to meet project requirements.  
Conduit couplings  
(supplied by installer)  
Fastener  
(2X)  
Trouble  
Alarm  
Power  
Test/reset  
switch  
Units equipped with factory-optional Return Air smoke  
detectors require a relocation of the sensor module at unit  
installation. See “Completing Installation of Return Air  
Smoke Sensor:” on page 37 for details.  
C08208  
Fig. 81 - Controller Assembly  
System —  
The smoke detector system consists of a four-wire  
controller and one or two sensors. Its primary function is  
to shut down the rooftop unit in order to prevent smoke  
from circulating throughout the building. It is not to be  
used as a life saving device.  
Duct smoke sensor  
Exhaust tube  
Controller —  
Exhaust gasket  
Sensor housing  
and electronics  
The controller (see Fig. 81) includes a controller housing,  
a printed circuit board, and a clear plastic cover. The  
controller can be connected to one or two compatible duct  
smoke sensors. The clear plastic cover is secured to the  
housing with a single captive screw for easy access to the  
wiring terminals. The controller has three LEDs (for  
Power, Trouble and Alarm) and a manual test/reset button,  
all located on the cover face.  
See  
Detail A  
Intake  
gasket  
Cover gasket  
(ordering option)  
TSD-CO2  
(ordering option)  
Sensor cover  
Plug  
Sampling tube  
(ordered separately)  
Sensor Module —  
Coupling  
The sensor module (see Fig. 82) includes a plastic housing, a  
printed circuit board, a clear plastic cover, a sampling tube  
inlet and an exhaust tube. The sampling tube (when used)  
and exhaust tube are attached during installation. The  
sampling tube varies in length depending on the size of the  
rooftop unit. The clear plastic cover permits visual  
inspections without having to disassemble the sensor. The  
cover attaches to the sensor housing using four captive  
screws and forms an airtight chamber around the sensing  
electronics. Each sensor includes a harness with an RJ45  
terminal for connecting to the controller. Each sensor has  
four LEDs (for Power, Trouble, Alarm and Dirty) and a  
manual test/reset button (on the left-side of the housing).  
Detail A  
Magnetic  
test/reset  
switch  
Alarm  
Trouble  
Power  
Dirty  
C08209  
Fig. 82 - Smoke Detector Sensor Module  
42  
Air is introduced to the duct smoke detector sensor’s  
sensing chamber through a sampling tube that extends into  
the HVAC duct and is directed back into the ventilation  
system through a (shorter) exhaust tube. The difference in  
air pressure between the two tubes pulls the sampled air  
through the sensing chamber. When a sufficient amount of  
smoke is detected in the sensing chamber, the sensor  
signals an alarm state and the controller automatically  
takes the appropriate action to shut down fans and  
blowers, change over air handling systems, notify the fire  
alarm control panel, etc.  
Return Air without Economizer —  
The sampling tube is located across the return air opening  
on the unit basepan. See Fig. 86. The holes in the  
sampling tube face downward, into the return air stream.  
The sampling tube is connected via tubing to the return air  
sensor that is mounted on a bracket high on the partition  
between return filter and controller location. (This sensor  
is shipped in a flat-mounting location. Installation  
requires that this sensor be relocated to its operating  
location and the tubing to the sampling tube be connected.  
See “Completing Installation of Return Air Smoke  
Sensor:” for details.)  
The sensor uses a process called differential sensing to  
prevent gradual environmental changes from triggering  
false alarms. A rapid change in environmental conditions,  
such as smoke from a fire, causes the sensor to signal an  
alarm state but dust and debris accumulated over time  
does not.  
Return Air with Economizer —  
The sampling tube is inserted through the side plates of  
the economizer housing, placing it across the return air  
opening on the unit basepan. See Fig. 84. The holes in the  
sampling tube face downward, into the return air stream.  
The sampling tube is connected via tubing to the return air  
sensor that is mounted on a bracket high on the partition  
between return filter and controller location. (This sensor  
is shipped in a flat-mounting location. Installation  
requires that this sensor be relocated to its operating  
location and the tubing to the sampling tube be connected.  
See the following installation procedure.)  
For installations using two sensors, the duct smoke  
detector does not differentiate which sensor signals an  
alarm or trouble condition.  
Smoke Detector Locations  
Supply Air —  
The Supply Air smoke detector sensor is located to the  
left of the unit’s indoor (supply) fan. See Fig. 83. Access  
is through the left side blower access panel. There is no  
sampling tube used at this location. The sampling tube  
inlet extends through the side plate of the fan housing  
(into a high pressure area). The controller is located on a  
bracket to the right of the return filter, accessed through  
the lift-off filter panel.  
Flexible  
Exhaust Tube  
Return Air  
Sampling Tube  
Smoke Detector Sensor  
C10330  
C08245  
Fig. 83 - Typical Supply Air Smoke Detector Sensor  
Location  
Fig. 84 - Return Air Sampling Tube Location  
43  
Completing Installation of Return Air Smoke Sensor:  
1. Unscrew the two screws holding the Return Air  
Sensor detector plate. See Fig. 85. Save the screws.  
2. Remove the Return Air Sensor and its detector plate.  
3. Rotate the detector plate so the sensor is facing out-  
wards and the sampling tube connection is on the bot-  
tom. See Fig. 86.  
4. Screw the sensor and detector plate into its operating  
position using screws from Step 1. Make sure the  
sampling tube connection is on the bottom and the ex-  
haust tube is on the top. See Fig. 86.  
5. Connect the flexible tube on the sampling inlet to the  
sampling tube on the basepan.  
Controller  
Screws  
Sampling Tube  
C10332  
Fig. 86 - Return Air Sensor Operating Position  
Flexible  
Exhaust  
Tubes  
Additional Application Data —  
Refer to Catalog No. HKRNKA-1XA for discussions on  
additional control features of these smoke detectors  
including multiple unit coordination.  
Sampling Tube  
C10331  
Fig. 85 - Return Air Detector Shipping Position  
44  
Table 10 – Unit Wire/Fuse or HACR Breaker Sizing Data  
COMBUSTION  
FAN MOTOR  
POWER  
EXHAUST  
NO C.O. or UNPWR C.O.  
w/ P.E. (pwrd fr/ unit)  
NO P.E.  
NOM.  
V --- P h --- H z  
IFM  
TYPE  
FUSE  
FUSE  
or  
HACR  
BRKR  
DISC. SIZE  
DISC. SIZE  
FLA  
FLA  
or  
MCA  
MCA  
HACR  
BRKR  
FLA  
LRA  
FLA  
LRA  
STD  
MED  
HIGH  
STD  
68.3  
70.8  
81.2  
34  
80  
80  
100  
45  
45  
50  
30  
30  
40  
71  
74  
86  
35  
37  
43  
28  
28  
35  
396  
413  
432  
234  
243  
252  
184  
184  
196  
72.1  
74.6  
85.0  
35.8  
36.8  
42.6  
30.3  
30.3  
36.5  
80  
90  
100  
45  
45  
50  
40  
40  
45  
76  
79  
91  
37  
39  
45  
32  
32  
39  
400  
417  
436  
236  
245  
254  
188  
188  
200  
208/230---3---60  
4 6 0 --- 3 --- 6 0  
0.48  
0.25  
0.24  
3.8  
1.8  
3.8  
MED  
HIGH  
STD  
35.0  
40.8  
26.5  
26.5  
32.7  
MED  
HIGH  
5 7 5 --- 3 --- 6 0  
Table 10 — Unit Wire/Fuse or HACR Breaker Sizing Data (cont)  
COMBUSTION  
FAN MOTOR  
POWER  
EXHAUST  
w/ PWRD C.O.  
NO P.E.  
w/ P.E. (pwrd fr/ unit)  
FUSE  
NOM.  
V --- P h --- H z  
IFM  
TYPE  
FUSE  
DISC. SIZE  
DISC. SIZE  
FLA  
FLA  
or  
or  
MCA  
MCA  
HACR  
BRKR  
HACR  
BRKR  
FLA  
LRA  
FLA  
LRA  
STD  
MED  
HIGH  
STD  
73.1  
75.6  
86.0  
36.2  
37.2  
43.0  
28.2  
28.2  
34.4  
80  
100  
100  
45  
77  
80  
92  
38  
39  
46  
30  
30  
37  
401  
418  
437  
236  
245  
254  
186  
186  
198  
76.9  
79.4  
89.8  
38  
100  
100  
100  
50  
81  
84  
96  
40  
41  
48  
34  
34  
41  
405  
422  
441  
238  
247  
256  
190  
190  
202  
208/230---3---60  
4 6 0 --- 3 --- 6 0  
0.48  
0.25  
0.24  
3.8  
1.8  
3.8  
MED  
HIGH  
STD  
50  
39.0  
44.8  
32  
50  
50  
50  
35  
40  
MED  
HIGH  
35  
32  
40  
5 7 5 --- 3 --- 6 0  
40  
38.2  
45  
Legend and Notes for Table 10  
LEGEND:  
Example: Supply voltage is 230-3-60  
BRKR  
CO  
--- Circuit breaker  
--- Convenience outlet  
--- Disconnect  
--- Full load amps  
--- Indoor fan motor  
--- Locked rotor amps  
--- Minimum circuit amps  
--- Po w e r e x h a u st  
--- Powered convenient outlet  
--- Unpowered convenient outlet  
AB = 224 v  
BC = 231 v  
AC = 226 v  
DISC  
FLA  
IFM  
LRA  
(224 + 231 + 226)  
681  
Average Voltage =  
3
=
MCA  
3
P. E .  
=
227  
PWRD CO  
UNPWR CO  
NOTES:  
Determine maximum deviation from average voltage.  
(AB) 227 – 224 = 3 v  
(BC) 231 – 227 = 4 v  
(AC) 227 – 226 = 1 v  
Maximum deviation is 4 v.  
1. In compliance with NEC requirements for multimotor and  
combination load equipment (refer to NEC Articles 430 and  
440), the overcurrent protective device for the unit shall be  
fuse or HACR breaker. Canadian units may be fuse or circuit  
breaker.  
Determine percent of voltage imbalance.  
2. Unbalanced 3-Phase Supply Voltage  
4
% Voltage Imbalance  
= 100 x  
= 1.76%  
Never operate a motor where a phase imbalance in supply  
voltage is greater than 2%. Use the following formula to de-  
termine the percentage of voltage imbalance.  
227  
This amount of phase imbalance is satisfactory as it is below the  
maximum allowable 2%.  
IMPORTANT: If the supply voltage phase imbalance is more than  
2%, contact your local electric utility company immediately.  
max voltage deviation from average voltage  
% Voltage Imbalance = 100 x  
average voltage  
45  
Unit Without Economizer or  
2 Position Damper  
Economizer  
2 Position Damper  
C10333  
Fig. 87 - EconoMi$ert IV Wiring  
Barometric relief  
Power Exhaust  
Step 13 — Adjust Factory--Installed Options  
Smoke Detectors —  
Differential dry-bulb sensor (EconoMi$er IV)  
Outdoor enthalpy sensor  
Differential enthalpy sensor  
Time Guard II compressor anti-cycle control  
Outdoor coil protector grille  
Head pressure control  
Programmable setback thermostat  
Electrical/Mechanical thermostat and subbase  
Thermidistatt device  
Humidistat  
Thermostat / Sensors  
CO2 sensor  
DDC interface (PremierLink)  
Louvered hail guard  
Smoke detector(s) will be connected at the Central Terminal  
Board (CTB), at terminals marked “Smoke Shutdown”.  
Remove jumper JMP 3 when ready to energize unit.  
EconoMi$er IV Occupancy Switch —  
Refer to Fig. 87 for general EconoMi$er IV wiring.  
External occupancy control is managed through a  
connection on the Central Terminal Board.  
If external occupancy control is desired, connect a time  
clock or remotely controlled switch (closed for Occupied,  
open for Unoccupied sequence) at terminals marked  
OCCUPANCY on CTB. Remove or cut jumper JMP 2 to  
complete the installation.  
Step 14 — Install Accessories  
Available accessories include:  
Phase monitor control  
Roof Curb (must be installed before unit)  
Thru-base connection kit (must be installed before unit  
is set on curb)  
Refer to separate installation instructions for information  
on installing these accessories.  
Pre--Start and Start--Up  
Manual outside air damper  
This completes the mechanical installation of the unit.  
Refer to the unit’s Service Manual for detailed Pre-Start  
and Start-up instructions.  
Two-Position motorized outside air damper  
EconoMi$er IV (with control and integrated barometric  
relief)  
EconoMi$er2 (without control/for external signal and  
integrated barometric relief)  
46  
47  
Catalog No: 48TC---14SI  
Copyright 2011 Carrier Corp. D 7310 W. Morris St. D Indianapolis, IN 46231  
Printed in U.S.A.  
Edition Date: 05/11  
Manufacturer reserves the right to change, at any time, specifications and designs without notice and without obligations.  
Replaces: 48TC---11SI  
48  

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