50VT---A
Performancet 14 SEER Single---Packaged Heat Pump
System with Puron® (R---410A) Refrigerant
Single and Three Phase
2 --- 5 N o m i n a l To n s ( S i z e s 2 4 --- 6 0 )
Installation Instructions
NOTE: Read the entire instruction manual before starting the
installation.
NOTE: Installer: Make sure the Owner’s Manual and Service
Instructions are left with the unit after installation.
TABLE OF CONTENTS
PAGE
SAFETY CONSIDERATIONS . . . . . . . . . . . . . . . . . . . . . . . . . 1
INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
RECEIVING AND INSTALLATION . . . . . . . . . . . . . . . . . . 2--9
Check Equipment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Identify Unit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Inspect Shipment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Provide Unit Support . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Roof Curb . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Slab Mount . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Provide Clearances . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Rig and Place Unit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Inspection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Rigging/Lifting of Unit . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Select and Install Ductwork . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Converting Horizontal Discharge Units to Downflow
A09033
(Vertical) Discharge Units . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Provide for Condensate Disposal . . . . . . . . . . . . . . . . . . . . . . 8
Install Electrical Connections . . . . . . . . . . . . . . . . . . . . . . . . . 8
High--Voltage Connections . . . . . . . . . . . . . . . . . . . . . . . . . 8
Special Procedures for 208--V Operation . . . . . . . . . . . . . . . 9
Control Voltage Connections . . . . . . . . . . . . . . . . . . . . . . . . 9
Standard Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Transformer Protection . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Accessory Electric heaters Installation . . . . . . . . . . . . . . . . . 9
Sequence of Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
PRE--START--UP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
START--UP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17--20
Checking Cooling & Heating Control Operation . . . . . . . . 17
Check for Refrigerant Leaks . . . . . . . . . . . . . . . . . . . . . . . . . 17
Start--Up Adjustments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Checking & Adjusting Refrigerant Charge . . . . . . . . . . . . 18
Indoor Airflow & Airflow Adjustments . . . . . . . . . . . . . . 18
Continuous Fan Operation . . . . . . . . . . . . . . . . . . . . . . . . 19
Defrost Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
Quiet Shift . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
Defrost . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
MAINTENANCE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23--28
Air Filter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
Indoor Blower and Motor . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
Outdoor Coil, Indoor Coil, & Condensate Drain Pan . . . . . . 26
Outdoor Fan . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
Electrical Controls and Wiring . . . . . . . . . . . . . . . . . . . . . . . 26
Refrigerant Circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
Indoor Airflow . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
Metering Devices-- TXV & Piston . . . . . . . . . . . . . . . . . . . . 26
Pressure Switches . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
Loss of Charge Switch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
High Pressure Switch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
Fig. 1 -- Unit 50VT--A
Copeland Scroll compressor (Puron Refrigerant) . . . . . . . . . 27
Refrigerant System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
Refrigerant . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
Compressor Oil . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
Servicing Systems on Roofs with Synthetic Materials . . . . 27
Liquid Line Filter Drier . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
PuronR (R--410A) Refrigerant Charging . . . . . . . . . . . . . 28
System Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
Loss of Charge Switch . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
Check Defrost Thermostat . . . . . . . . . . . . . . . . . . . . . . . . . 28
TROUBLESHOOTING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
START--UP CHECKLIST . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
SAFETY CONSIDERATIONS
Installation and servicing of this equipment can be hazardous due
to mechanical and electrical components. Only trained and
qualified personnel should install, repair, or service this equipment.
Untrained personnel can perform basic maintenance functions such
as cleaning and replacing air filters. All other operations must be
performed by trained service personnel. When working on this
equipment, observe precautions in the literature, on tags, and on
labels attached to or shipped with the unit and other safety
precautions that may apply.
Follow all safety codes. Wear safety glasses, protective clothing,
and work gloves. Use quenching cloth for brazing operations.
Have
a
fire extinguisher available. Read these instructions
thoroughly and follow all warnings or cautions included in
literature and attached to the unit. Consult local building codes, the
current editions of the National Electrical Code (NEC) NFPA 70.
In Canada refer to the current editions of the Canadian Electrical
Code CSA C22.1.
1
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A09410
Fig. 2 -- 50VT--A24--30 Unit Dimensions
3
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A09411
Fig. 3 -- 50VT--A36--60 Unit Dimensions
4
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Dashed lines show cross support
location for large basepan units.
B
G
C
HVAC unit
basepan
HVAC unit
base rails
Sealing
Gasket
Roofcurb
H
F
A
Anchor screw
Wood nailer*
Roofcurb*
Flashing field
supplied
Insulation
(field supplied)
Roofing material
field supplied
E
D
Cant strip
field supplied
A09413
SMALL/COMMON CURB
*Provided with roofcurb
A09090
ROOF CURB DETAIL
B
C
SMALL
BASE
UNIT
SUPPLY
AIR
G
H
A
LARGE
BASE
UNIT
F
RETURN
AIR
E
D
UNIT PLACEMENT ON
COMMON CURB
A09094
A09415
SMALL OR LARGE BASE UNIT
LARGE CURB
A09414
Fig. 4 -- Roof Curb Dimensions
A
B (small/common
C
F
UNIT
SIZE
CATALOG
NUMBER
B (large base)
IN. (mm)*
D
E
G
H
IN.
base)
IN.
IN.
IN. (mm)
IN. (mm)
IN. (mm)
IN. (mm)
(mm)
IN. (mm)*
(mm)
(mm)
Small
or
CPRFCURB010A00 11 (279)
10 (254)
14 (356)
32.4 (822)
30.6 (778)
CPRFCURB011A00 14 (356)
CPRFCURB012A00 11 (279)
CPRFCURB013A00 14 (356)
Large
14 (356)
16 (406) 47.8 (1214)
2.7 (69)
46.1 (1170)
Large
43.9 (1116)
42.2 (1072)
* Part Numbers CPRCURB010A00 and CPRCURB011A00 can be used on both small and large basepan units. The cross supports must be located based on
whether the unit is a small basepan or a large basepan.
NOTES:
1. Roof curb must be set up for unit being installed.
2. Seal strip must be applied, as required, to unit being installed.
3. Roof curb is made of 16---gauge steel.
4. Attach ductwork to curb (flanges of duct rest on curb).
5. Insulated panels: 1---in. (25 mm) thick fiberglass 1 lb. density.
5
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CAUTION - NOTICE TO RIGGERS
PRUDENCE - AVIS AUX MANIPULATEUR
ACCESS PANELS MUST BE IN PLACE WHEN RIGGING.
PANNEAUX D'ACCES DOIT ÊTRE EN PLACE POUR MANIPULATION.
Use top skid as spreader bar. / Utiliser la palette du haut comme barre de répartition
DUCTS
MINIMUM HEIGHT: 36" (914.4 mm)
HAUTEUR MINIMUM
BANDE SCELLANT DOIT ÊTRE
EN PLACE AVANT DE PLACER
L'UNITÉ SUR LA BASE DE TOIT
SEAL STRIP MUST BE IN
PLACE BEFORE PLACING
UNIT ON ROOF CURB
UNIT HEIGHT
HAUTEUR D'UNITÉ
DETAIL A
VOIR DÉTAIL A
SEE DETAIL A
VOIR DÉTAIL A
50CY502286 2.0
A09051
RIGGING WEIGHTS (SMALL CABINET)
RIGGING WEIGHTS (LARGE CABINET)
36* 42* 48*
24
30
60*
Unit
Unit
lb
kg
lb
kg
lb
kg
lb
kg
lb
kg
lb
kg
Rigging
Weight
Rigging
Weight
354
161
346
157
426
193
472
214
460
209
506
230
* For 460 volt units, add 14 lb (6.4 kg) to the weight.
NOTE: See dimensional drawing for corner weight distribution.
Fig. 5 -- Rigging Weights
Step 4 — Rig and Place Unit
Rigging and handling of this equipment can be hazardous for
many reasons due to the installation location (roofs, elevated
structures, etc.).
!
WARNING
UNIT FALLING HAZARD
Failure to follow this warning could result in personal
injury or death.
Only trained, qualified crane operators and ground support staff
should handle and install this equipment.
When working with this equipment, observe precautions in the
literature, on tags, stickers, and labels attached to the equipment,
and any other safety precautions that might apply.
Training for operators of the lifting equipment should include, but
not be limited to, the following:
Never stand beneath rigged units or lift over people.
1. Leave top shipping skid on the unit for use as a spreader bar
to prevent the rigging straps from damaging the unit. If the
skid is not available, use a spreader bar of sufficient length
to protect the unit from damage.
1. Application of the lifter to the load, and adjustment of the
lifts to adapt to various sizes or kinds of loads.
!
WARNING
2. Instruction in any special operation or precaution.
PROPERTY DAMAGE HAZARD
3. Condition of the load as it relates to operation of the lifting
kit, such as balance, temperature, etc.
Failure to follow this warning could result in personal injury
or death.
Follow all applicable safety codes. Wear safety shoes and work
gloves.
When straps are taut, the clevis should be a minimum of 36
in. (914 mm) above the unit top cover.
Inspection
Prior to initial use, and at monthly intervals, all rigging shackles,
clevis pins, and straps should be visually inspected for any damage,
evidence of wear, structural deformation, or cracks. Particular
attention should be paid to excessive wear at hoist hooking points
and load support areas. Materials showing any kind of wear in
these areas must not be used and should be discarded.
Rigging/Lifting of Unit (See Fig. 5)
Lifting holes are provided in base rails as shown.
1. Attach shackles, clevis pins, and straps to the base rails of
the unit. Be sure materials are rated to hold the weight of the
unit (See Fig. 5).
2. Attach a clevis of sufficient strength in the middle of the
straps. Adjust the clevis location to ensure unit is lifted level
with the ground.
After the unit is placed on the roof curb or mounting pad, remove
the top skid.
6
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CONFIGURING UNITS FOR DOWNFLOW
(VERTICAL) DISCHARGE
Step 5 — Select and Install Ductwork
The design and installation of the duct system must be in
accordance with the standards of the NFPA for installation of
non--residence type air conditioning and ventilating systems,
NFPA 90A or residence--type, NFPA 90B and/or local codes and
ordinances.
!
WARNING
ELECTRICAL SHOCK HAZARD
Failure to follow this warning could result in personal
injury or death.
Select and size ductwork, supply--air registers, and return air grilles
according to ASHRAE (American Society of Heating,
Refrigeration, and Air Conditioning Engineers) recommendations.
Before performing service or maintenance operations on the
system, turn off main power to unit and install lockout tag.
There may be more than one disconnect switch.
The unit has duct flanges on the supply-- and return--air openings
on the side of the unit.
1. Open all electrical disconnects and install lockout tag before
starting any service work.
2. Remove horizontal (metal) ductcovers to access vertical
(downflow) discharge duct knockouts in unit basepan. (See
Fig. 6.)
!
WARNING
PERSONAL INJURY HAZARD
Failure to follow this warning could result in personal
injury or death.
3. To remove downflow return and supply knockout covers,
For vertical supply and return units, tools or parts could
drop into ductwork Install a 90 degree turn in the return
ductwork between the unit and the conditioned space. If a
90 degree elbow cannot be installed, then a grille of
sufficient strength and density should be installed to
prevent objects from falling into the conditioned space.
Units with electric heaters require 90 degree elbow in
supply duct.
break front and right side connecting tabs with
a
screwdriver and hammer. Push cover down to break rear
and left side tabs.
When designing and installing ductwork, consider the following:
1. All units should have field--supplied filters or accessory
filter rack installed in the return--air side of the unit.
Recommended sizes for filters are shown in Table 1.
2. Avoid abrupt duct size increases and reductions. Abrupt
change in duct size adversely affects air performance.
IMPORTANT: Use flexible connectors between ductwork and
unit to prevent transmission of vibration. Use suitable gaskets to
ensure weather tight and airtight seal. When electric heat is
installed, use fireproof canvas (or similar heat resistant material)
connector between ductwork and unit discharge connection. If
flexible duct is used, insert a sheet metal sleeve inside duct. Heat
resistant duct connector (or sheet metal sleeve) must extend 24--in.
(610 mm) from electric heater element.
Horizontal Duct Covers
A09076
Basepan
Downflow
(Vertical)
Supply
Knockout
Basepan
Downflow
(Vertical)
Return
3. Size ductwork for cooling air quantity (cfm). The minimum
air quantity for proper electric heater operation is listed in
Table 2. Heater limit switches may trip at air quantities
below those recommended.
Knockout
A09093
4. Seal, insulate, and weatherproof all external ductwork. Seal,
insulate and cover with a vapor barrier all ductwork passing
through conditioned spaces. Follow latest Sheet Metal and
Air Conditioning Contractors National Association
(SMACNA) and Air Conditioning Contractors Association
(ACCA) minimum installation standards for residential
heating and air conditioning systems.
5. Secure all ducts to building structure. Flash, weatherproof,
and vibration--isolate duct openings in wall or roof
according to good construction practices.
Fig. 6 -- Supply and Return Duct Opening
NOTE: These panels are held in place with tabs similar to an
electrical knockout. Reinstall horizontal duct covers (Fig. 6)
shipped on unit from factory. Insure openings are air and
watertight.
NOTE: The design and installation of the duct system must be in
accordance with the standards of the NFPA for installation of
nonresidence--type air conditioning and ventilating systems, NFPA
90A or residence--type, NFPA 90B; and/or local codes and
ordinances.
Adhere to the following criteria when selecting, sizing, and
installing the duct system:
1. Units are shipped for side shot installation.
2. Select and size ductwork, supply--air registers, and
return--air grilles according to American Society of Heating,
Refrigeration and Air Conditioning Engineers (ASHRAE)
recommendations.
3. Use flexible transition between rigid ductwork and unit to
prevent transmission of vibration. The transition may be
7
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screwed or bolted to duct flanges. Use suitable gaskets to
ensure weather--tight and airtight seal.
4. All units must have field--supplied filters or accessory filter
rack installed in the return--air side of the unit.
Recommended sizes for filters are shown in Table 1.
5. Size all ductwork for maximum required airflow (either
heating or cooling) for unit being installed. Avoid abrupt
duct size increases or decreases or performance may be
affected.
least 1 in. (25 mm) every 10 ft (3 m) of horizontal run. Be sure to
check the drain trough for leaks. Prime the trap at the beginning of
the cooling season start--up.
TRAP
OUTLET
1-in. (25 mm) min.
2-in. (51 mm) min.
6. Adequately insulate and weatherproof all ductwork located
outdoors. Insulate ducts passing through unconditioned
space, and use vapor barrier in accordance with latest issue
of Sheet Metal and Air Conditioning Contractors National
Association (SMACNA) and Air Conditioning Contractors
of America (ACCA) minimum installation standards for
heating and air conditioning systems. Secure all ducts to
building structure.
A09052
Fig. 9 -- Condensate Trap
Step 7 — Install Electrical Connections
!
CAUTION
UNIT COMPONENT DAMAGE HAZARD
7. Flash, weatherproof, and vibration--isolate all openings in
building structure in accordance with local codes and good
building practices.
Failure to follow this caution may result in damage to the unit
being installed.
1. Make all electrical connections in accordance with NEC
NFPA 70 (latest edition) and local electrical codes
governing such wiring. In Canada, all electrical
connections must be in accordance with CSA standard
C22.1 Canadian Electrical Code Part 1 and applicable
local codes. Refer to unit wiring diagram.
2. Use only copper conductor for connections between
field--supplied electrical disconnect switch and unit. DO
NOT USE ALUMINUM WIRE.
A
C
MAXIMUM ALLOWABLE
DIFFERENCE in. (mm)
B
B-C
(6.35)
A-B
(6.35)
A-C
(6.35)
1/4
1/4
1/4
3. Be sure that high--voltage power to unit is within
operating voltage range indicated on unit rating plate. On
3--phase units, ensure phases are balanced within 2
percent. Consult local power company for correction of
improper voltage and/or phase imbalance.
A07925
Fig. 7 -- Unit Leveling Tolerances
OPTIONAL
RETURN
AIR
OPTIONAL
SUPPLY
AIR
OPENING
OPENING
4. Do not damage internal components when drilling
through any panel to mount electrical hardware, conduit,
etc.
2˝
(50.8mm)
!
WARNING
EVAP. COIL
COND. COIL
ELECTRICAL SHOCK HAZARD
A07926
Failure to follow this warning could result in personal injury
or death.
Fig. 8 -- Slab Mounting Detail
Step 6 — Provide for Condensate Disposal
NOTE: Ensure that condensate--water disposal methods comply
with local codes, restrictions, and practices.
The unit cabinet must have an uninterrupted, unbroken
electrical ground. This ground may consist of an electrical
wire connected to the unit ground screw in the control
compartment, or conduit approved for electrical ground when
installed in accordance with NEC,NFPA 70 National Fire
Protection Association (latest edition) (in Canada, Canadian
Electrical Code CSA C22.1) and local electrical codes.
The 50VT--A units dispose of condensate through a 3/4 in. NPT
female fitting that exits on the compressor end of the unit.
Condensate water can be drained directly onto the roof in rooftop
installations (where permitted) or onto a gravel apron in ground
level installations. Install a field--supplied condensate trap at end of
condensate connection to ensure proper drainage. Make sure that
the outlet of the trap is at least 1 in. (25 mm) lower than the
drain--pan condensate connection to prevent the pan from
overflowing. Prime the trap with water. When using a gravel apron,
make sure it slopes away from the unit.
High-Voltage Connections
The unit must have
a
separate electrical service with
a
field--supplied, waterproof disconnect switch mounted at, or within
sight from the unit. Refer to the unit rating plate, NEC and local
codes for maximum fuse/circuit breaker size and minimum circuit
amps (ampacity) for wire sizing.
If the installation requires draining the condensate water away from
the unit, install a field--supplied 2 --in. (51mm) trap at the
condensate connection to ensure proper drainage. Condensate trap
is available as an accessory or is field--supplied. Make sure that the
outlet of the trap is at least 1 in. (25 mm) lower than the unit
drain--pan condensate connection to prevent the pan from
The field--supplied disconnect may be mounted on the unit over
the high--voltage inlet hole when the standard power and
low--voltage entry points are used. See Fig. 2 and 3 for acceptable
location. Remove high voltage knockout.
See unit wiring label (Fig. 12--14) and Fig. 10 for reference when
making high voltage connections. Proceed as follows to complete
the high--voltage connections to the unit.
overflowing. Connect
a
drain tube using
a
minimum of
field--supplied 3/4--in. PVC or field--supplied 3/4--in. copper pipe
at outlet end of the 2--in. (51 mm) trap. (See Fig. 9) Do not
undersize the tube. Pitch the drain tube downward at a slope of at
8
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control voltage wires), use no. 16 AWG color--coded, insulated
(35° C minimum) wires.
HIGH VOLTAGE
POWER LEADS
(SEE UNIT WIRING
LABEL)
POWER
SUPPLY
Standard Connections
Locate the eight (nine on 3--phase) low voltage thermostat leads in
24 volt splice box. See Fig. 10 for connection diagram. Run the
low--voltage leads from the thermostat, through the control wiring
inlet hole grommet (Fig. 2 and 3), and into the low--voltage splice
box. Provide a drip loop before running wires through panel.
Secure and strain relief all wires so that they do not interfere with
operation of unit. A gray wire is standard on 3--phase units for
connection to an economizer.
3-PHASE SHOWN
1-PHASE USES
TWO POWER
EQUIP GR
LEADS
FIELD-SUPPLIED
FUSED DISCONNECT
CONTROL BOX
WHT(W1)
W1
W2
Y
VIO (W2)
YEL(Y)
GRN(G)
If an accessory electric heater is installed, low voltage leads from
heater must be connected to factory supplied control leads from
Indoor Fan Board P4 connector.
NOTE: If the unit 24V wires do not have a matching receptacle,
cut the 24V wires from the electric heater plug, strip the ends, and
wire nut together to match the schematic connections. If the electric
heater 24V wires do not have a matching plug, cut the 24V wires
from the unit receptacle, strip the ends, and wire nut together to
match the schematic connections.
G
THERMOSTAT
(TYPICAL)
LOW-VOLTAGE
POWER LEADS
RED(R)
BRN(C)
R
)
(SEE UNIT
C
O
WIRING LABEL
ORN(O)
BLU(DH)
GRA(Y2)
DH
3-Phase
Only
SPLICE BOX
A09071
Factory wires are provided for electric heat staging W1 and W2
(W2 and W3 on IFB). If room thermostat has only one stage of
supplemental heat, connect white and violet wires shown in Fig. 10
to second stage heat field wire.
Some electric heaters have four control wires (plus common wire).
Consult unit wiring diagram and electric heater wiring diagram for
additional details.
Fig. 10 -- High-- and Control--Voltage Connections
Single phase units:
1. Run the high--voltage (L1, L2) and ground lead into the
control box.
2. Connect ground lead to chassis ground connection.
3. Locate the black and yellow wires connected to the line side
of the contactor.
4. Connect field L1 to black wire on connection 11 of the
compressor contactor.
5. Connect field wire L2 to yellow wire on connection 23 of
the compressor contactor.
Transformer Protection
The transformer is of the energy--limiting type. It is set to withstand
a 30--second overload or shorted secondary condition. If an
overload or short is present, correct overload condition and check
for blown fuse on Interface Fan Board. Replace fuse as required
with correct size and rating.
Three--phase units:
1. Run the high--voltage (L1, L2, L3) and ground lead into the
control box.
2. Connect ground lead to chassis ground connection.
Accessory Electric Heaters Installation
Electric heaters may be installed with the 50VT--A units per
instructions supplied with electric heater package. See unit rating
plate for factory--approved electric heater kits.
3. Locate the black and yellow wires connected to the line side
of the contactor.
Sequence of Operation
4. Connect field L1 to black wire on connection 11 of the
compressor contactor.
5. Connect field wire L3 to yellow wire on connection 13 of
the compressor contactor.
a. CONTINUOUS FAN
(1.) Thermostat closes circuit R to G energizing the
blower motor for continuous fan.
b. COOLING MODE
6. Connect field wire L2 to blue wire from compressor.
(1.) If indoor temperature is above temperature set
point, thermostat closes circuits R to G, R to Y and
R to O--The unit delivers cooling airflow.
Special Procedures for 208-V Operation
c. ELECTRIC HEATING MODE
(1.) Thermostat closes circuit R to W/W1, or W2 and R
to G. There are no on or off delays.
!
WARNING
ELECTRICAL SHOCK HAZARD
d. HEAT PUMP HEATING MODE
Failure to follow this warning could result in personal
injury or death.
(1.) Thermostat closes circuits R to G and R to Y. The
compressor, indoor and outdoor fans are energized.
e. HEAT PUMP HEATING WITH AUXILIARY
ELECTRIC HEAT
Before installing or servicing system, always turn off main
power to system. Tag the disconnect switch with a suitable
warning label. With disconnect switch open, move black
wire from transformer (3/16 in.) terminal marked 230 to
terminal marked 208. This retaps transformer to primary
voltage of 208 vac.
(1.) Thermostat closes circuits R to G, R to Y and R to
W/W1 or W2. The compressor, indoor and outdoor
fans are energized, as well as the electric heat
relays.
f. DEFROST MODE
Control Voltage Connections
The defrost mode is automatically energized by the
defrost board during heating mode. The defrost board
energizes “O” (reversing valve) and “W2” (electric
heat). It also de--energizes the outdoor fan. When defrost
is complete, unit will return to heating mode. If room
thermostat is satisfied during defrost, unit will shut
down and restart in defrost on next call for heat.
NOTE: Do not use any type of power--stealing thermostat. Unit
control problems may result.
Use no. 18 American Wire Gage (AWG) color--coded, insulated
(35°C minimum) wires to make the control voltage connections
between the thermostat and the unit. If the thermostat is located
more than 100 ft (30.5 m) from the unit (as measured along the
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Table 1 – Physical Data -- Unit 50VT--A
50VT-A24
50VT-A30
2.5
50VT-A36
50VT-A42
3.5
50VT-A48
50VT-A60
Unit Size
2
3
4
5
Shipping Weight (lb)
(kg)
354
161
346
426
193
472
460
209
506
230
157
214
Compressor Quantity
Type
1
Scroll
Refrigerant
R-410A
Refrigerant Quantity (lb)
Quantity (kg)
11.1
5.0
10.3
4.7
9.9
4.5
11.3
5.1
12.5
5.7
15.2
6.9
Refrigerant Metering Device
Orifice OD (in)
(mm)
Indoor TXV, Outdoor Dual Accuraters
0.032 (2)
0.81 (2)
0.037 (2)
0.94 (2)
0.038 (2)
0.97 (2)
0.040 (2)
1.02 (2)
0.040 (2)
1.02 (2)
0.049 (2)
1.24 (2)
Outdoor Coil
Rows...Fins/in,
face area (sq. ft.)
Outdoor Fan
2...21
13.6
2...21
13.6
2...21
13.6
2...21
17.5
2...21
17.5
2...21
23.3
Nominal Airflow (cfm)
Diameter (in.)
Diameter (mm)
Motor hp (rpm)
Indoor Coil
2500
24
610
2700
24
610
3100
26
660
3100
26
660
3100
26
660
3500
26
660
1/10 (810)
1/5 (810)
1/5 (810)
1/5 (810)
1/5 (810)
1/4 (810)
Rows...Fins/in,
face area (sq. ft.)
Indoor Blower
Nominal Airflow (cfm)
Size (in.)
3...17
3.7
3...17
3.7
3...17
4.7
3...17
4.7
3...17
5.6
3...17
5.6
800
10 x 10
254 x 254
1/2
1000
10 x 10
254 x 254
1/2
1200
11 x 10
279 x 254
3/4
1400
11 x 10
279 x 254
3/4
1600
11 x 10
279 x 254
1
1750
11 x 10
279 x 254
1
Size (mm)
Motor hp (rpm)
High Pressure Switch (psig)
Cutout
650 +/- 15
420 +/- 25
Reset (Auto)
Loss-of-Charge/Low Pressure Switch (psig)
Cutout
20 +/- 5
45 +/- 10
Reset (Auto)
Return Air Filters
disposable (in)
(mm)
20x20x1
508x508x25
20x24x1
508x610x25
24x30x1
610x762x25
24x36x1
610x914x25
*Required filter sizes shown are based on the larger of the AHRI (Air Conditioning Heating and Refrigeration Institute) rated cooling airflow or the heating airflow
velocity of 300 ft/minute for throwaway type or 450 ft/minute for high---capacity type. Air filter pressure drop for non---standard filters must not exceed 0.08 IN.
W.C.
{ If using accessory filter rack refer to the filter rack installation instructions for correct filter size and quantity.
}
For 460 volt units, add 14 lb (6.4 kg) to the weight.
Table 2 – Minimum Airflow for Reliable Electric Heater Operation (CFM)
SIZE
AIRFLOW (CFM)
50VT -A24
50VT -A30
50VT -A36
50VT -A42
50VT -A48
50VT -A60
800
1025
1250
1400
1710
1800
INDOOR
THERMOSTAT
RETURN
AIR
FROM
TOP COVER
POWER
SOURCE
DISCONNECT
PER NEC
POWER ENTRY
CONTROL ENTRY
A09098
Fig. 11 -- Typical Installation
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A11002
Fig. 12 -- Connection Wiring Schematics 208/230--1--60
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A11001
Fig. 12 Cont. -- Ladder Wiring Schematics 208/230--1--60
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A11006
Fig. 13 -- Connection Wiring Schematics -- 208/230--3--60
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A11005
Fig. 13 Cont. -- Ladder Wiring Schematics -- 208/230--3--60
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A10195
Fig. 14 -- Connection Wiring Diagram 460--3--60
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A10195
Fig. 14 Cont. -- Ladder Wiring Diagram 460--3--60
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high--side Schrader fitting located on the compressor
discharge line. Be sure that caps on the ports are tight.
PRE--START--UP
START--UP
!
WARNING
Checking Cooling and Heating Control Operation
FIRE, EXPLOSION, ELECTRICAL SHOCK AND
ENVIRONMENTAL HAZARD
Start and check the unit for proper control operation as follows:
(1.) Place room thermostat SYSTEM switch or MODE
control in OFF position. Observe that blower
motor starts when FAN mode is placed in FAN ON
position and shuts down when FAN MODE switch
is placed in AUTO position.
Failure to follow this warning could result in personal injury,
death or property damage.
1. Follow recognized safety practices and wear protective
goggles when checking or servicing refrigerant system.
2. Relieve and recover all refrigerant from system before
touching or disturbing compressor plug if refrigerant
leak is suspected around compressor terminals.
3. Do not remove compressor plug until all electrical
sources are disconnected and tagged.
4. Never attempt to repair soldered connection while
refrigerant system is under pressure.
(2.) Thermostat:
When the room temperature rises to a point that is
slightly above the cooling control setting of the
thermostat, the thermostat completes the circuit
between thermostat terminal R to terminals Y, O
and G.These completed circuits through the
thermostat connect contactor coil (C) (through unit
wire Y) and Indoor Fan board (through unit wire
G) across the 24--v. secondary of transformer
(TRAN).
5. Do not use torch to remove any component. System
contains oil and refrigerant under pressure.
To remove a component, wear protective goggles and
proceed as follows:
(3.) Place system switch or MODE control in HEAT
position. Set control above room temperature.
Observe that compressor, outdoor fan, and indoor
blower motors start. Observe that heating cycle
shuts down when control setting is satisfied.
(4.) When using an automatic changeover room
thermostat place both SYSTEM or MODE control
and FAN mode switches in AUTO positions.
Observe that unit operates in Cooling mode when
temperature control is set to “call for Cooling”
(below room temperature), and unit operates in
Heating mode when temperature control is set to
“call for Heating” (above room temperature).
NOTE: Once the compressor has started and then has stopped, it
should not be started again until 5 minutes have elapsed. The
defrost board has a built--in 5 minute delay between cycles. The 5
minute compressor delay also applies to heat pump heating mode.
a. Shut off electrical power to unit and install lockout
tag.
b. Relieve and reclaim all refrigerant from system
using both high-- and low--pressure ports.
c. Cut component connecting tubing with tubing
cutter and remove component from unit.
d. Carefully unsweat remaining tubing stubs when
necessary. Oil can ignite when exposed to torch
flame.
Use the Start--Up Checklist supplied at the end of this book and
proceed as follows to inspect and prepare the unit for initial
start--up:
1. Remove all access panels (see Fig. 21).
2. Read and follow instructions on all DANGER, WARNING,
CAUTION, and INFORMATION labels attached to, or
shipped with, unit.
Step 1 — Check for Refrigerant Leaks
Proceed as follows to locate and repair a refrigerant leak and to
charge the unit:
3. Make the following inspections:
a. Inspect for shipping and handling damages such as
broken lines, loose parts, disconnected wires, etc.
1. Locate leak and make sure that refrigerant system pressure
has been relieved and reclaimed from both high-- and
low--pressure ports.
b. Inspect for oil at all refrigerant tubing connections and
on unit base. Detecting oil generally indicates a
refrigerant leak. Leak--test all refrigerant tubing
connections using electronic leak detector, or
2. Repair leak following Refrigerant Service procedures.
NOTE: Install a bi--flow filter drier whenever the system has been
opened for repair.
liquid--soap solution. If a refrigerant leak is detected, see
following Check for Refrigerant Leaks section.
3. Add a small charge of R--410A refrigerant vapor to system
and leak--test unit.
c. Inspect all field and factory--wiring connections. Be sure
that connections are completed and tight. Ensure wires
do not touch refrigerant tubing or sharp sheet metal
edges.
d. Inspect coil fins. If damaged during shipping and
handling, carefully straighten fins with a fin comb.
4. Recover refrigerant from refrigerant system and evacuate to
500 microns if no additional leaks are not found.
5. Charge unit with Puron (R--410A) refrigerant, using an
electronic scale. Refer to unit rating plate for required
charge.
Step 2 — Start--Up Adjustments
4. Verify the following conditions:
Complete the required procedures given in the Pre--Start--Up
section before starting the unit. Do not jumper any safety devices
when operating the unit. Do not operate the unit in Cooling mode
when the outdoor temperature is below 40_F (4_C) (unless
accessory low--ambient kit is installed).
a. Make sure that outdoor--fan blade is correctly positioned
in fan orifice.
b. Make sure that air filter(s) is in place.
c. Make sure that condensate drain pan and trap are filled
with water to ensure proper drainage.
d. Make sure that all tools and miscellaneous loose parts
have been removed.
IMPORTANT: Three--phase, scroll compressors are direction
oriented. Unit must be checked to ensure proper compressor
3--phase power lead orientation. If not corrected within 5 minutes,
the internal protector will shut off the compressor. The 3--phase
power leads to the unit must be reversed to correct rotation. When
5. Each unit system has 2 Schrader--type ports, one low--side
Schrader fitting located on the suction line, and one
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turning backwards, the difference between compressor suction and
discharge pressures may be near zero.
!
WARNING
Checking and Adjusting Refrigerant Charge
The refrigerant system is fully charged with Puron (R--410A)
refrigerant and is tested and factory sealed.
ELECTRICAL SHOCK HAZARD
Failure to follow this warning could result in personal
injury or death.
NOTE:
Adjustment of the refrigerant charge is not required
Disconnect electrical power to the unit and install lockout
tag before changing blower speed.
unless the unit is suspected of not having the proper Puron
(R--410A) charge.
A subcooling charging chart is attached to the inside of the
compressor access panel (see Fig. 21). The chart includes the
required liquid line temperature at given discharge line pressures
and outdoor ambient temperatures.
This unit is factory-set up for use with a single cooling fan speed.
In addition, this unit has the field-selectable capability to run two
different cooling fan speeds: The rated cooling fan speed (350~400
CFM/Ton) and an enhanced dehumidification fan speed (As low as
320 CFM/Ton) for use with either a dehumidistat or a thermostat
that supports dehumidification.
An accurate thermocouple-- or thermistor--type thermometer, and a
gauge manifold are required when using the subcooling charging
method for evaluating the unit charge. Do not use mercury or small
dial--type thermometers because they are not adequate for this type
of measurement.
NOTE: Allow system to operate for a minimum of 15 minutes
before checking or adjusting refrigerant charge.
The cooling speed is marked “LOW” on the interface fan board
(IFB) (See Fig. 16) . The factory-shipped settings are noted in
Table 4. There are 4 additional speed tap wires available for use in
either electric heating or cooling (For color coding on the indoor
fan motor leads, see Table 3). The additional 4 speed tap wires are
shipped loose with vinyl caps and are located in the control box,
near the interface fan board (IFB) (See Fig. 16).
IMPORTANT: When evaluating the refrigerant charge, an
indicated adjustment to the specified factory charge must always be
very minimal. If a substantial adjustment is indicated, an abnormal
condition exists somewhere in the cooling system, such as
insufficient airflow across either coil or both coils.
Single Cooling Fan Speed Set-up (Dehumidification
feature not used)
To change cooling speed:
Proceed as follows:
1. Remove the vinyl cap off of the desired speed tap wire
(Refer to Table 3 for color coding). Add the wet coil
pressure drop in Table 7 to the system static to determine the
correct cooling airflow speed in Table 4 that will deliver the
nominal cooling airflow as listed in Table 1 for each size.
1. Remove caps from low-- and high--pressure service fittings.
2. Using hoses with valve core depressors, attach low-- and
high--pressure gauge hoses to low-- and high--pressure
service fittings, respectively.
3. Start unit and let run until system pressures stabilize.
4. Measure and record the following:
2. Remove the current speed tap wire from the “LOW”
terminal on the interface fan board (IFB) (See Fig. 16) and
place vinyl cap over the connector on the wire.
3. Connect the desired speed tap wire to the “LOW” terminal
on the interface fan board (IFB).
a. Outdoor ambient--air temperature (°F [°C] db).
b. Liquid line temperature (°F [°C]) at TXV.
c. Discharge (high--side) pressure (psig).
NOTE: If accessory electric heat is installed, and the electric heat
fan speed is chosen to be the same as the normal cooling fan speed,
the dry airflow must meet or exceed the minimum airflow speed
specified in Table 2 for the specific size unit.
d. Suction (low--side) pressure (psig) (for reference only).
5. Using Cooling Charging Charts compare outdoor--air
temperature (°F [°C] db) with the discharge line pressure
(psig) to determine desired system operating liquid line
temperature (See Fig. 18).
6. Compare actual liquid line temperature with desired liquid
line temperature. Using a tolerance of ±2°F (±1.1°C), add
refrigerant if actual temperature is more than 2°F (1.1°C)
higher than proper liquid line temperature, or remove
refrigerant if actual temperature is more than 2°F (1.1°C)
lower than required liquid line temperature.
Two Cooling Fan Speeds Set-up (Dehumidification
feature used)
IMPORTANT: Dehumidification control must open control
circuit on humidity rise above set point.
Use of the dehumidification cooling fan speed requires use of
either a 24 VAC dehumidistat or a thermostat which includes
control of a 24 VAC dehumidistat connection. In either case, the
dehumidification control must open the control circuit on humidity
rise above the dehumidification set point.
NOTE:
If the problem causing the inaccurate readings is a
refrigerant leak, refer to Check for Refrigerant Leaks section.
Indoor Airflow and Airflow Adjustments
1. Using Fig. 16, move the two pin DEHUM jumper from the
“STD” position to the “DEHUM” position.
2. Remove fan speed tap wire from the “LOW” terminal on
the interface fan board (IFB) (See Fig. 16).
3. Determine correct normal cooling fan speed for unit and
application. Add the wet coil pressure drop in Table 7 to
the system static to determine the correct cooling airflow
speed in Table 4 that will deliver the nominal cooling
airflow as listed in Table 1 for each size.
!
CAUTION
UNIT OPERATION HAZARD
Failure to follow this caution may result in unit damage.
For cooling operation, the recommended airflow is 350 to
450 cfm for each 12,000 Btuh of rated cooling capacity. For
heating operation, the airflow must produce a temperature
rise that falls within the range stamped on the unit rating
plate.
NOTE: If accessory electric heat is installed, the dry
airflow must meet or exceed the minimum airflow speed
specified in Table 2 for the specific size unit. The electric
heat fan speed will be the same as the normal cooling fan
speed.
NOTE: Be sure that all supply--and return--air grilles are open,
free from obstructions, and adjusted properly.
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4. Remove the vinyl cap off of the desired speed tap wire
(Refer to Table 3 for color coding) for the normal cooling
fan speed and place desired speed tap wire on “HIGH” on
the interface board.
!
CAUTION
UNIT OPERATION HAZARD
5. Refer to airflow tables (Table 4) to determine allowable
speeds for the dehumidification cooling fan speed. In Table
4, speeds that are not allowed for dehumidification cooling
are shaded.
Failure to follow this caution may result in unit component
damage or improper operation.
To use this mode, a speed connection must be made on the
“HIGH” terminal that meets or exceeds the minimum
airflow found in Table 2.
6. Remove the vinyl cap off of the desired speed tap wire
(Refer to Table 3 for color coding) for the dehumidification
cooling fan speed and place desired speed tap wire on the
“LOW” connection on the interface board (IFB). Verify
that static pressure is in the acceptable range for the speed
tap to be used for dehumidification cooling.
Table 3 – Color Coding for Indoor Fan Motor Leads
Black = High Speed
Orange = Med--High Speed
Red = Med Speed
Pink = Med--Low Speed
7. Use any spare vinyl plugs to cap any unused speed tap
wires.
Blue = Low Speed
Single Speed Cooling With Higher Electric Heat Speed
This unit can also be configured to operate with single speed
cooling and a higher speed for an accessory electric heater.
!
WARNING
1. Move the two pin DEHUM jumper located on control
board (see Fig. 16) from the “STD” position to the
“DEHUM” position.
ELECTRICAL SHOCK HAZARD
Failure to follow this warning could result in personal
injury or death.
2. See Table 2 for minimum airflow for electric heat operation.
Add electric heater and filter pressure drop to duct system
static pressure to determine total external static pressure.
Disconnect electrical power to the unit and install lockout
tag before changing blower speed.
3. Select speed tap from Table 4 that will achieve required
airflow from Table 2.
Continuous Fan Operation
When the DEHUM feature is not used, the continuous fan speed
will be the same as cooling fan speed. When the DEHUM feature
is used, the continuous fan will operate on IFB “LOW” speed
when the DH control lead is not energized, or IFB “HIGH” speed
when the DH lead is energized (see Fig. 16).
4. Remove the vinyl cap off of the desired speed tap wire
(Refer to Table 3 for color coding).
5. Connect the desired speed tap wire to the “HIGH” terminal
on the interface fan board (IFB).
INDOOR COIL
OUTDOOR COIL
TXV in Metering
Position
LCS
HPS
Bypass
Position
LEGEND
HPS – High Pressure Switch
LCS – Loss of Charge Switch
®
Accurater Metering Device
Arrow indicates direction of flow
C03011
Fig. 15 -- Typical Heat Pump Operation, Cooling Mode
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HIGH
QC5
LOW
QC4
COM
QC3
KL
D2
KZ
DCR
QCR
QC1
C
R13 C8 R11
Q1
07 09 0L0 08
ALO
Q3
AL2
C9
RL
C4
G1
G2
01
QIL
Z2 06 04
A7 R9 AB A15
F1
C0
Z1
U1
R4
RL4
C3
D5 D3
C7
JWZ
JW5
QCB
R3 R5 R6
P2 JW3
R2
P4
Y
R
W2
Y
C
W3 W3 W2 W2
JW4
C
SSTZ-8
P1
Y2
DH
Y1
Y
W3 W2
G
C
R
A09059
Fig. 16 -- Interface Fan Board (IFB)
INDOOR COIL
OUTDOOR COIL
TXV in Bypass
Position
LCS
HPS
Metering
Position
LEGEND
HPS – High Pressure Switch
LCS – Loss of Charge Switch
®
Accurater Metering Device
Arrow indicates direction of flow
C03012
Fig. 17 -- Typical Heat Pump Operation, Heating Mode
If defrost thermostat is closed, speed--up pins (J1) must be shorted
by placing a flat head screw driver in between for 5 sec and
releasing, to observe a complete defrost cycle. When the Quiet
Shift switch is selected, compressor will be turned off for two 30
sec intervals during this complete defrost cycle, as explained
previously. When Quiet Shift switch is in factory default OFF
position, a normal and complete defrost cycle will be observed.
Step 3 — Defrost Control
Quiet Shift
Quiet Shift is a field--selectable defrost mode, which will eliminate
occasional noise that could be heard at the start of defrost cycle and
restarting of heating cycle. It is selected by placing DIP switch 3
(on defrost board) in ON position.
When Quiet Shift switch is placed in ON position, and a defrost is
initiated, the following sequence of operation will occur. Reversing
valve will energize, outdoor fan will turn off, compressor will turn
off for 30 sec and then turn back on to complete defrost. At the
start of heating after conclusion of defrost reversing valve will
de--energize, compressor will turn off for another 30 sec, and the
outdoor fan will stay off for 40 sec, before starting in the Heating
mode.
If defrost thermostat is in open position, and speedup pins are
shorted (with a flat head screw driver) for 5 sec and released, a
short defrost cycle will be observed (actual length is dependent
upon the selected Quiet Shift position). When Quiet Shift switch is
in ON position, the length of defrost is 1 minute (30 sec
compressor off period followed by 30 sec of defrost with
compressor operation). On return to heating operation, compressor
will again turn off for an additional 30 sec and the outdoor fan for
40 sec. When the Quiet Shift is in OFF position, only a brief 30
sec. cycle will be observed.
Defrost
The defrost control is a time/temperature control which includes a
field--selectable time period (DIP switch 1 and 2 on the board)
between defrost cycles of 30, 60, 90, or 120 minutes (factory set at
60 minutes). To initiate a forced defrost, two options are available
depending on the status of the defrost thermostat.
NOTE: Unit will remain in defrost until defrost thermostat
reopens at approximately 65_F (18_C) coil temperature at liquid
line or remainder of defrost cycle time.
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Indoor Blower and Motor
NOTE: All motors are pre--lubricated. Do not attempt to lubricate
these motors.
MAINTENANCE
To ensure continuing high performance, and to minimize the
possibility of premature equipment failure, periodic maintenance
must be performed on this equipment. This heat pump unit should
be inspected at least once each year by a qualified service person.
To troubleshoot unit, refer to Table 10.
NOTE: 460 volt units have a stepdown autotransformer that
supplies approximately 230 volts to a nominal 230 volt indoor
blower motor.
NOTE: TO EQUIPMENT OWNER: Consult your local dealer
about the availability of a maintenance contract.
For longer life, operating economy, and continuing efficiency,
clean accumulated dirt and grease from the blower wheel and
motor annually.
!
WARNING
!
WARNING
PERSONAL INJURY AND UNIT DAMAGE HAZARD
ELECTRICAL SHOCK HAZARD
Failure to follow this warning could result in personal injury
or death and unit component damage.
Failure to follow this warning could result in personal injury
or death.
The ability to properly perform maintenance on this
equipment requires certain expertise, mechanical skills, tools
and equipment. If you do not possess these, do not attempt to
perform any maintenance on this equipment, other than those
procedures recommended in the Owner’s Manual.
Disconnect and tag electrical powerto theunit beforecleaning
the blower motor and wheel.
To clean the blower motor and wheel:
1. Remove and disassemble blower assembly as follows:
a. Remove blower access panel (see Fig 22).
!
WARNING
b. Disconnect 5 pin plug and 4 pin plug from indoor
blower motor. Remove capacitor if required.
ELECTRICAL SHOCK HAZARD
c. On all units remove blower assembly from unit.
Remove screws securing blower to blower partition and
slide assembly out. Be careful not to tear insulation in
blower compartment.
Failure to follow these warnings could result in personal
injury or death:
1. Turn off electrical power to the unit and install a lockout
tag before performing any maintenance or service on this
unit.
d. Ensure proper reassembly by marking blower wheel and
motor in relation to blower housing before disassembly.
2. Use extreme caution when removing panels and parts.
e. Loosen setscrew(s) that secures wheel to motor shaft,
remove screws that secure motor mount brackets to
housing, and slide motor and motor mount out of
housing.
3. Never place anything combustible either on or in contact
with the unit.
2. Remove and clean blower wheel as follows:
a. Ensure proper reassembly by marking wheel orientation.
!
CAUTION
b. Lift wheel from housing. When handling and/or
cleaning blower wheel, be sure not to disturb balance
weights (clips) on blower wheel vanes.
UNIT OPERATION HAZARD
Failure to follow this caution may result in improper
operation.
c. Remove caked--on dirt from wheel and housing with a
brush. Remove lint and/or dirt accumulations from
wheel and housing with vacuum cleaner, using soft
brush attachment. Remove grease and oil with mild
solvent.
Errors made when reconnecting wires may cause improper
and dangerous operation. Label all wires prior to
disconnecting when servicing.
d. Reassemble wheel into housing.
The minimum maintenance requirements for this equipment are as
follows:
e. Reassemble motor into housing. Be sure setscrews are
tightened on motor shaft flats and not on round part of
shaft. Reinstall blower into unit. Reinstall capacitor.
1. Inspect air filter(s) each month. Clean or replace when
necessary.
f. Connect 5 pin plug and 4 pin plug to indoor blower
motor.
2. Inspect indoor coil, drain pan, and condensate drain each
cooling season for cleanliness. Clean when necessary.
g. Reinstall blower access panel (see Fig. 21).
3. Inspect blower motor and wheel for cleanliness each
cooling season. Clean when necessary.
3. Restore electrical power to unit. Start unit and check for
proper blower rotation and motor speeds during cooling
cycles.
4. Check electrical connections for tightness and controls for
proper operation each cooling season. Service when
necessary.
Step 1 — Air Filter
IMPORTANT: Never operate the unit without a suitable air filter
in the return--air duct system. Always replace the filter with the
same dimensional size and type as originally installed. See Table 1
for recommended filter sizes.
Inspect air filter(s) at least once each month and replace
(throwaway--type) or clean (cleanable--type) at least twice during
each cooling season and twice during the heating season, or
whenever the filter becomes clogged with dust and lint.
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A09412
Fig. 18 -- Cooling Charging Table--Subcooling
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Speedup
Pins
Quiet
Shift
Defrost interval
DIP switches
A08020
Fig. 19 -- Defrost Control
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If no refrigerant leaks are found and low performance is suspected,
refer to Checking and Adjusting Refrigerant Charge section.
Step 2 — Outdoor Coil, Indoor Coil, and
Condensate Drain Pan
Inspect the condenser coil, evaporator coil, and condensate drain
pan at least once each year.
The coils are easily cleaned when dry; therefore, inspect and clean
the coils either before or after each cooling season. Remove all
obstructions, including weeds and shrubs, that interfere with the
airflow through the condenser coil.
Straighten bent fins with a fin comb. If coated with dirt or lint,
clean the coils with a vacuum cleaner, using the soft brush
attachment. Be careful not to bend the fins. If coated with oil or
grease, clean the coils with a mild detergent--and--water solution.
Rinse coils with clear water, using a garden hose. Be careful not to
splash water on motors, insulation, wiring, or air filter(s). For best
results, spray condenser coil fins from inside to outside the unit. On
units with an outer and inner condenser coil, be sure to clean
between the coils. Be sure to flush all dirt and debris from the unit
base.
Step 6 — Indoor Airflow
The heating and/or cooling airflow does not require checking
unless improper performance is suspected. If a problem exists, be
sure that all supply--air and return--air grilles are open and free
from obstructions, and that the air filter is clean. When necessary,
refer to Indoor Airflow and Airflow Adjustments section to check
the system airflow.
Step 7 — Metering Devices--TXV & Piston
This unit uses 2 types of metering devices. The outdoor metering
device is a fixed orifice and is contained in the brass hex--body in
each liquid line feeding the outdoor coils. The indoor metering
device is a TXV type device.
Inspect the drain pan and condensate drain line when inspecting
the coils. Clean the drain pan and condensate drain by removing all
foreign matter from the pan. Flush the pan and drain trough with
clear water. Do not splash water on the insulation, motor, wiring, or
air filter(s). If the drain tube is restricted, clear it with a plumbers
snake or similar probe device.
Step 3 — Outdoor Fan
Keep the condenser fan free from all obstructions to ensure proper
cooling operation. Never place articles on top of the unit. Damage
to unit may result.
1. Remove 6 screws holding outdoor grille and motor to top
cover.
2. Turn motor/grille assembly upside down on top cover to
expose fan blade.
3. Inspect the fan blades for cracks or bends.
4. If fan needs to be removed, loosen setscrew and slide fan off
motor shaft.
C99097
5. When replacing fan blade, position blade back to same posi-
tion as before.
Fig. 20 -- Refrigerant Circuit
6. Ensure that setscrew engages the flat area on the motor shaft
when tightening.
7. Replace grille.
Step 4 — Electrical Controls and Wiring
Inspect and check the electrical controls and wiring annually. Be
sure to turn off the electrical power to the unit.
Remove access panels (see Fig 22) to locate all the electrical
controls and wiring. Check all electrical connections for tightness.
Tighten all screw connections. If any discolored or burned
connections are noticed, disassemble the connection, clean all the
parts, restrip the wire end and reassemble the connection properly
and securely.
After inspecting the electrical controls and wiring, replace all the
panels. Start the unit, and observe at least one complete cooling
cycle to ensure proper operation. If discrepancies are observed in
operating cycle, or if a suspected malfunction has occurred, check
each electrical component with the proper electrical
instrumentation. Refer to the unit wiring label when making these
checkouts.
Control
Access
Panel
Blower
Access
Panel
Step 5 — Refrigerant Circuit
Inspect all refrigerant tubing connections and the unit base for oil
Compressor
Access Panel
accumulation annually. Detecting oil generally indicates
refrigerant leak.
a
A09214
Fig. 21 -- Unit Access Panels
If oil is detected or if low performance is suspected, leak--test all
refrigerant tubing using an electronic leak detector, or liquid--soap
solution. If a refrigerant leak is detected, refer to Check for
Refrigerant Leaks section.
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Refrigerant
Step 8 — Pressure Switches
Pressure switches are protective devices wired into control circuit
(low voltage). They shut off compressor if abnormally high or low
pressures are present in the refrigeration circuit. These pressure
switches are specifically designed to operate with Puron (R--410A)
systems. R--22 pressure switches must not be used as replacements
for the Puron (R--410A) system.
!
WARNING
PROPERTY HAZARD, PERSONAL INJURY OR
ENVIRONMENTAL HAZARD
Failuretofollowthiswarning couldresult in propertydamage
or personal injury or death.
Step 9 — Loss of Charge Switch
This system uses Puron (R--410A) refrigerant which has
higher operating pressures than R--22 and other refrigerants.
No other refrigerant may be used in this system. Gauge set,
hoses, and recoverysystem mustbe designedto handlePuron.
If you are unsure consult the equipment manufacturer.
This switch is located on the liquid line and protects against low
suction pressures caused by such events as loss of charge, low
airflow across indoor coil, dirty filters, etc. It opens on a pressure
drop at about 20 psig. If system pressure is above this, switch
should be closed. To check switch:
1. Turn off all power to unit.
2. Disconnect leads on switch.
Compressor Oil
The Copeland scroll compressor uses 3MAF POE oil. If additional
oil is needed, use Uniqema RL32--3MAF. If this oil is not
available, use Copeland Ultra 32 CC or Mobil Arctic EAL22 CC.
This oil is extremely hygroscopic, meaning it absorbs water
readily. POE oils can absorb 15 times as much water as other oils
designed to HCFC and CFC refrigerants. Take all necessary
precautions to avoid exposure of the oil to the atmosphere.
3. Apply ohm meter leads across switch. You should have
continuity on a good switch.
NOTE: Because these switches are attached to refrigeration
system under pressure, it is not advisable to remove this device for
troubleshooting unless you are reasonably certain that a problem
exists. If switch must be removed, remove and recover all system
charge so that pressure gauges read 0 psig. Never open system
without breaking vacuum with dry nitrogen.
Servicing Systems on Roofs with Synthetic Materials
POE (polyolester) compressor lubricants are known to cause long
term damage to some synthetic roofing materials. Exposure, even if
immediately cleaned up, may cause embrittlement (leading to
cracking) to occur in one year or more. When performing any
service that may risk exposure of compressor oil to the roof, take
appropriate precautions to protect roofing. Procedures which risk
oil leakage include, but are not limited to, compressor replacement,
repairing refrigerant leaks, replacing refrigerant components such
as filter drier, pressure switch, metering device, coil, accumulator,
or reversing valve.
Step 10 — High--Pressure Switch
The high--pressure switch is located in the discharge line and
protects against excessive condenser coil pressure. It opens at 650
psig.
High pressure may be caused by a dirty outdoor coil, failed fan
motor, or outdoor air recirculation.
To check switch:
1. Turn off all power to unit.
2. Disconnect leads on switch.
3. Apply ohm meter leads across switch. You should have
continuity on a good switch.
Synthetic Roof Precautionary Procedure
1. Cover extended roof working area with an impermeable
polyethylene (plastic) drip cloth or tarp. Cover an
approximate 10x10 ft (3x3 m) area.
Step 11 — Copeland Scroll Compressor (Puron
Refrigerant)
The compressor used in this product is specifically designed to
operate with Puron (R--410A) refrigerant and cannot be
interchanged.
2. Cover area in front of the unit service panel with a terry
cloth shop towel to absorb lubricant spills and prevent
run--offs, and protect drop cloth from tears caused by tools
or components.
3. Place terry cloth shop towel inside unit immediately under
component(s) to be serviced and prevent lubricant run--offs
through the louvered openings in the unit base.
!
WARNING
4. Perform required service.
EXPLOSION HAZARD
5. Remove and dispose of any oil contaminated material per
local codes.
Failure to follow this warning could result in personal injury,
death or property damage.
Liquid Line Filter Drier
Wear safety glasses and gloves when handling refrigerants.
Keep torches and other ignition sources away from refrigerant
and oils.
The biflow filter drier is specifically designed to operate with
Puron. Use only factory--authorized components. Filter drier must
be replaced whenever the refrigerant system is opened. When
removing a filter drier, use a tubing cutter to cut the drier from the
system. Do not unsweat a filter drier from the system. Heat from
unsweating will release moisture and contaminants from drier into
system.
The scroll compressor pumps refrigerant throughout the system by
the interaction of a stationary and an orbiting scroll. The scroll
compressor has no dynamic suction or discharge valves, and it is
more tolerant of stresses caused by debris, liquid slugging, and
flooded starts. The compressor is equipped with an internal
pressure relief port. The pressure relief port is a safety device,
designed to protect against extreme high pressure. The relief port
has an operating range between 550 and 625 psig differential
pressure.
Step 12 — Refrigerant System
This step covers the refrigerant system of the 50VT--A, including
the compressor oil needed, servicing systems on roofs containing
synthetic materials, the filter drier and refrigerant charging.
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The defrost thermostat signals heat pump that conditions are right
for defrost or that conditions have changed to terminate defrost. It
is a thermally actuated switch clamped to outdoor coil to sense its
temperature. Normal temperature range is closed at 32_ 3_F (0
1.7_C) and open at 65_ 5_F (18 2.8_C).
NOTE: The defrost thermostat must be located on the liquid side
of the outdoor coil on the bottom circuit and as close to the coil as
possible.
Puron (R-410A) Refrigerant Charging
Refer to unit information plate and charging chart. Some R--410A
refrigerant cylinders contain a dip tube to allow liquid refrigerant to
flow from cylinder in upright position. For cylinders equipped
with a dip tube, charge Puron units with cylinder in upright
position and a commercial metering device in manifold hose.
Charge refrigerant into suction--line.
Step 13 — System Information
Loss of Charge Switch
The loss of charge switch is a protective device wired into control
circuit (low voltage). It shuts off the compressor if abnormally low
pressures are present in the refrigeration circuit.
FEEDER TUBE
STUB TUBE
NOTE: Because these switches are attached to refrigeration
system under pressure, it is not advisable to remove this device for
troubleshooting unless you are reasonably certain that a problem
exists. If switch must be removed, remove and recover all system
charge so that pressure gauges read 0 psig. Never open system
without breaking vacuum with dry nitrogen.
DEFROST
THERMOSTAT
Check Defrost Thermostat
The defrost thermostat is usually located on the lowest liquid
leaving circuit of the left condenser coil (see Fig. 22). The
thermostat closes at 32_F (0_C) and opens at 65_F (18_C).
C99029
Fig. 22 -- Defrost Thermostat
TROUBLESHOOTING
Refer to the Cooling and Heating Troubleshooting Chart (Table
10) for troubleshooting information.
START--UP CHECKLIST
Use the Start--Up Checklist.
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PURONR (R--410A) QUICK REFERENCE GUIDE
S
Puron refrigerant operates at 50--70 percent higher pressures than R--22. Be sure that servicing equipment and replacement
components are designed to operate with Puron
S
S
S
Puron refrigerant cylinders are rose colored.
Recovery cylinder service pressure rating must be 400 psig, DOT 4BA400 or DOT BW400.
Puron systems should be charged with liquid refrigerant. Use a commercial type metering device in the manifold hose when
charging into suction line with compressor operating
S
S
S
S
S
S
S
S
S
S
S
S
S
S
S
Manifold sets should be minimum 700 psig high side and 180 psig low side with 550 psig low--side retard.
Use hoses with minimum 700 psig service pressure rating.
Leak detectors should be designed to detect HFC refrigerant.
Puron, as with other HFCs, is only compatible with POE oils.
Vacuum pumps will not remove moisture from oil.
Do not use liquid--line filter driers with rated working pressures less than 600 psig.
Do not leave Puron suction line filter driers in line longer than 72 hours.
Do not install a suction--line filter drier in liquid line.
POE oils absorb moisture rapidly. Do not expose oil to atmosphere.
POE oils may cause damage to certain plastics and roofing materials.
Wrap all filter driers and service valves with wet cloth when brazing.
A factory approved liquid--line filter drier is required on every unit.
Do NOT use an R--22 TXV.
Never open system to atmosphere while it is under a vacuum.
When system must be opened for service, recover refrigerant, evacuate then break vacuum with dry nitrogen and replace filter
driers. Evacuate to 500 microns prior to recharging.
S
S
S
Do not vent Puron into the atmosphere.
Observe all warnings, cautions, and bold text.
All indoor coils must be installed with a hard shutoff Puron TXV metering device.
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Table 10 – Troubleshooting Chart
SYMPTOM
CAUSE
REMEDY
Call power company
Power failure
Fuse blown or circuit breaker tripped
Replace fuse or reset circuit breaker
Defective contactor, transformer, or high--pressure,
loss--of--charge or low--pressure switch
Replace component
Compressor and condenser fan will not start.
Insufficient line voltage
Incorrect or faulty wiring
Determine cause and correct
Check wiring diagram and rewire correctly
Lower thermostat setting below room tempera-
ture
Thermostat setting too high
Faulty wiring or loose connections in compressor cir-
cuit
Check wiring and repair or replace
Compressor motor burned out, seized, or
internal overload open
Defective run/start capacitor, overload, start relay
Determine cause
Replace compressor
Determine cause and replace
Compressor will not start but condenser fan
runs
Replace fuse or reset circuit breaker
Determine cause
One leg of 3--phase power dead
Three--phase scroll compressor
makes excessive noise, and there may be a
low pressure differential.
Correct the direction of rotation by reversing the
3--phase power leads to the unit.
Scroll compressor is rotating in the wrong direction
Refrigerant overcharge or undercharge
Recover refrigerant, evacuate system, and re-
charge to capacities shown on rating plate
Defective compressor
Insufficient line voltage
Blocked condenser
Defective run/start capacitor, overload or start relay
Defective thermostat
Replace and determine cause
Determine cause and correct
Determine cause and correct
Determine cause and replace
Replace thermostat
Compressor cycles (other than normally sat-
isfying thermostat).
Faulty condenser--fan motor or capacitor
Restriction in refrigerant system
Dirty air filter
Replace
Locate restriction and remove
Replace filter
Unit undersized for load
Thermostat set too low
Decrease load or increase unit size
Reset thermostat
Low refrigerant charge
Mechanical damage in compressor
Locate leak, repair, and recharge
Replace compressor
Compressor operates continuously
Recover refrigerant, evacuate system, and re-
charge
Air in system
Condenser coil dirty or restricted
Dirty air filter
Clean coil or remove restriction
Replace filter
Dirty condenser coil
Clean coil
Refrigerant overcharged
Recover excess refrigerant
Recover refrigerant, evacuate system, and re-
charge
Excessive head pressure
Air in system
Condenser air restricted or air short--cycling
Low refrigerant charge
Compressor IPR leaking
Restriction in liquid tube
High heat load
Compressor IPR leaking
Refrigerant overcharged
Dirty air filter
Determine cause and correct
Check for leaks, repair, and recharge.
Replace compressor
Remove restriction
Check for source and eliminate
Replace compressor
Head pressure too low
Excessive suction pressure
Recover excess refrigerant
Replace filter
Low refrigerant charge
Metering device or low side restricted
Check for leaks, repair and recharge
Remove source of restriction
Increase air quantity
Check filter–replace if necessary
Insufficient evaporator airflow
Suction pressure too low
Temperature too low in conditioned area
Outdoor ambient below 55°F (12.7°C)
Filter drier restricted
Reset thermostat
Install low--ambient kit
Replace filter
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START--UP CHECKLIST
(Remove and Store in Job Files)
I. PRELIMINARY INFORMATION
MODEL NO.:
SERIAL NO.:
DATE:
TECHNICIAN:
II. PRESTART--UP (Insert check mark in box as each item is completed)
( ) VERIFY THAT ALL PACKING MATERIALS HAVE BEEN REMOVED FROM UNIT
( ) REMOVE ALL SHIPPING HOLD DOWN BOLTS AND BRACKETS PER INSTALLATION INSTRUCTIONS
( ) CHECK ALL ELECTRICAL CONNECTIONS AND TERMINALS FOR TIGHTNESS
( ) CHECK THAT INDOOR (EVAPORATOR) AIR FILTER IS CLEAN AND IN PLACE
( ) VERIFY THAT UNIT INSTALLATION IS LEVEL
( ) CHECK FAN WHEEL, AND PROPELLER FOR LOCATION IN HOUSING/ORIFICE AND SETSCREW TIGHTNESS
III. START--UP
ELECTRICAL
SUPPLY VOLTAGE
COMPRESSOR AMPS
INDOOR (EVAPORATOR) FAN AMPS
TEMPERATURES
OUTDOOR (CONDENSER) AIR TEMPERATURE
RETURN--AIR TEMPERATURE
DB
DB
WB
COOLING SUPPLY AIR
DB
WB
HEAT PUMP SUPPLY AIR _____________________
ELECTRIC HEAT SUPPLY AIR _____________
PRESSURES
REFRIGERANT SUCTION
PSIG, SUCTION LINE TEMP*
REFRIGERANT DISCHARGE
PSIG, LIQUID TEMP{
( ) VERIFY REFRIGERANT CHARGE USING CHARGING CHARTS
* Measured at suction inlet to compressor
{
Measured at liquid line leaving condenser.
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Catalog No: 50VT---09SI
Copyright 2011 Carrier Corp. S 7310 W. Morris St. S Indianapolis, IN 46231
Edition Date: 01/11
Manufacturer reserves the right to change, at any time, specifications and designs without notice and without obligations.
Replaces: 50VT---08SI
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