Flotronic Plus Reciprocating Liquid Chillers
HEATING
COOLING
Controls Troubleshooting Guide
Model E Units Have Microprocessor Controls
and Electronic Expansion Valves
CONTENTS
SAFETY CONSIDERATIONS
Page
1
Installation, start-up and servicing of this equipment
can be hazardous due to system pressures, electrical
components and equipment location.
Only trained, qualified installers and service mechanics
should install, start-up and service this equipment.
SAFETY
. . . . . . . . . . . . . . . .
FLOTRONIC PLUS CONTROL SYSTEM . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1
2
When working on the equipment, observe precautions
in the literature, tags, stickers and labels attached to the
.
l
PROCESSOR MODULE . . . . . . . . . . . . . . . . . . .
2
2
LOW-VOLTAGE RELAY MODULE . . . . . . . . .
equipment and any
safety precautions that apply.
. EXV
EXPANSION
VALVE) DRIVER MODULE . . . . . . . . . . . . . . .
2
l
Follow all safety codes.
Wear safety glasses and
.
KEYBOARD AND DISPLAY MODULE . . . . .
ELECTRONIC EXPANSION VALVE . . . . . . . .
THERMISTORS . . . . . . . . . . . . . . . . . . . . . . . . . . .
CONTROL . . . . . . . . . . . . . . . . . . . .
2
3
gloves.
.
l
l
Use care in handling, rigging and setting bulky
equipment.
l
3
3
.
Use care in handling
components.
CONTROL
SEQUENCE . . . . . . . . . . . . . . . . . . . . .
Off Cycle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Start-Up . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Capacity Control . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4
4
4
4
5
5
5
5
SHOCK HAZARD.
Open all remote disconnects before
this equipment.
l
SEQUENCE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Unit Shutdown . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . .
Complete Unit Stoppage
Single-Circuit Stoppage . . . . . . . . . . . . . . . . . . . . .
Lag Compressor Stoppage . . . . . . . . . . . . . . . . . . .
Restart Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . .
5
l
GENERAL POWER
. . . . . . . . . . . . . .
5
This unit uses a
control system.
to short out components, bypass or otherwise depart
electronic
not use jumpers or other tools
l
BLOWN FUSE
POWER FEED
DISCONNECT . . . . . . . . . . . . . . . . . . . . . . . . . . . .
LOW WATER TEMPERATURE
5
l
from
procedures. Any
CUTOUT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
AUXILIARY INTERLOCK . . . . . . . . . . . . . . . . .
5
5
5
5
5
ground of the control
or accompanying wiring
l
l
may destroy the electronic modules or electrical
component.
OPEN CONTROL
FUSE . . . . . . . . . .
.
FREEZE PROTECTION . . . . . . . . . . . . . . . . . . . .
HIGH-PRESSURE SWITCH . . . . . . . . . . . . . . . .
l
LOSS OF CHARGE SWITCH . . . . . . . . . . . . . . .
COMPRESSOR DISCHARGE
TEMPERATURE SWITCH . . . . . . . . . . . . . . . . .
OIL SAFETY SWITCH . . . . . . . . . . . . . . . . . . . . .
5
.
5
5
.
FLOTRONIC PLUS CONTROL SYSTEM
CONTROLS OPERATION . . . . . . . . . . . . . . . . . .
I
General
The
Flotronic Plus chillers
Accessing Functions and Subfunctions. . . . . . .
5
5
feature microprocessor-based electronic controls and an
electronic expansion valve (EXV) in each refrigeration
circuit.
Functions . . . . . . . . . . . . . . . . . . . . . . . . . . .
SUMMARY DISPLAY . . . . . . . . . . . . . . . . . . . . .
5
.
STATUS FUNCTION . . . . . . . . . . . . . . . . . . . . . .
TEST FUNCTION . . . . . . . . . . . . . . . . . . . . . . . .
5
.
10
The Flotronic Plus control system cycles compressors
and compressor unloaders to maintain the selected leav-
ing water temperature set point. It automatically posi-
tions the EXV to maintain the specified refrigerant
superheat entering the cylinders of the compressor.
Safeties are continuously monitored to prevent the unit
from operating under unsafe conditions. A scheduling
function, programmed by the user, controls the unit
occupied/ unoccupied schedule. The control also operates
a Quick Test program that allows the operator to check
input and output signals to the microprocessor.
. . . . . . . . . . . . . . . . . . . .
Functions
FUNCTION . . . . . . . . . . . . . . . . . . . .
Programming
1
.
l
11
SET POINT FUNCTION . . . . . . . . . . . . . . . . . .
SCHEDULE FUNCTION . . . . . . . . . . . . . . . . . .
l
11
TROUBLESHOOTING
. . . . . . . . . . . . . . . . . . . . .
12-26
Checking Display Codes . . . . . . . . . . . . . . . . . . . .
1
2
12
l
OPERATING MODE CODES . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . .
.
ALARM CODES
12
1 4
Quick Test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Electronic Expansion Valves . . . . . . . . . . . . . . . .
1 9
l
The control system consists of a processor module
(PSIO), low-voltage relay module (DSIO), electronic
expansion valve (EXV), EXV driver module (DSIO),
keyboard and display module (HSIO) and thermistors to
provide analog inputs to the microprocessor. The soft-
ware resides in the PSIO.
l
EXV OPERATION . . . . . . . . . . . . . . . . . . . . . . . .
Thermistors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
l
l
Modules . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
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Each function has one or more subfunctions as shown
in Table 2. These functions are defined in greater detail
in t Controls Operation section of this book.
At initial start-up the valve position is initialized to 0.
After that, the microprocessor keeps accurate track of the
valve position in order to use this information as input for
the other control functions.
The control monitors the superheat and the rate of
change of superheat to control the position of the valve.
The valve stroke is very large; this results in very accurate
control of the superheat.
The electronic expansion valve is also used to limit the
maximum saturated suction temperature to 55 F (12.8 C)
to keep from overloading the compressor during high
cooler water temperatures. This allows the unit to start
with very warm water temperatures.
THERMISTORS
The electronic control uses 7 ther-
mistors to sense temperatures used to control the opera-
tion of the chiller. Sensors are listed in Table 3.
Fig. 2
Keyboard and Display Module
EXPANSION VALVE
The micro-
processor controls the expansion valve through
CAPACITY CONTROL
The control cycles com-
the EXV driver module. Inside the expansion valve is a
linear actuator stepper motor. To control the stepper
motor’s position, the thermistor in the cooler and the
thermistor in the lead compressor in each circuit are used
to maintain a 20 F (1 I C) difference. Because the com-
pressor sensor is after the compressor motor, which adds
pressors and alternately loads and unloads cylinders to
give capacity control steps as shown in Table 4. The unit
controls leaving chilled water temperature. Entering
water temperature is used by the microprocessor in deter-
mining the optimum time to load and unload, but is not a
control set point.
approximately 15 F (8.3 C) superheat, the 20 F
C)
control temperature results in to 5 F (2.8 C) super-
heat leaving the cooler. This improves the performance of
the cooler.
The chilled water temperature set point can be auto-
matically reset by the return temperature reset or space
and outside air temperature reset features.
Table 2
Function and Subfunctions
FUNCTIONS
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Table 3
Thermistors
CONTROL SEQUENCE
The control power (115-l-60 for units; 230-l-50
for 50-Hz units) must be supplied directly from a separate
source through a code-approved fused disconnect to the
and
terminals of unit power teminal block.
NOTE: There is no switch or circuit breaker; only fuses. If
the control power feed is live, so is the circuit.
Crankcase heaters are wired into the control circuit.
They are always operative as long as control circuit
power is on even though unit may be off because of
safety device action. Heaters are wired so they are on only
when their respective compressors are cycled off.
a
the
heaters
the unit.
should be on
24
When power is supplied to control circuit, unit is ready
for operation providing all safety devices are satisfied,
interlocks are closed and instructions on warning labels
have been followed.
If schedule function is used, refer to page 11 for details
on control operation.
Table 4
Capacity Control Steps
Off Cycle
STANDBY switch is in the
crankcase heaters and the control system are energized.
During unit off cycle when the RUN;
ENCE
SEQUENCE A
position, the
er
Cylinders
Cylinders
UNIT
3 0 H R
3 0 H S
STEPS
The electronic expansion valves are
energized.
Cap.
C a p .
C o m p r
C o m p r
(NOTE: The control circuit power must be on at all times
even when the main unit power is off.)
14.3
4 2 . 9
5 7 . 2
7 1 . 2
8 5 . 7
100.0
2
4
6
4 2 . 9
5 7 . 2
7 1 . 2
8 5 . 7
0 0 . 0
Start-Up
moved from the STANDBY to the RUN position and
there is a call for cooling, after l-l to 3 minutes have
When the RUN/STANDBY switch is
a
0 7 0
0 8 0
090
1 0
1 2
1 4
1 0
4
4
passed the first compressor will start unloaded, The first
circuit to start may be circuit A or B due to the automatic
lead/ lag feature.
2 5 . 0
5 0 . 0
6 2 . 5
7 5 . 0
8 7 . 5
100.0
4
2 5 . 0
5 0 . 0
6 2 . 5
7 5 . 0
8 7 . 5
0 0 . 0
4
a
1 0
1 2
1 4
1 6
Capacity Control
(See Table 4.) The rate at which
1 6
the compressors are turned on will depend on the leaving
water temperature difference from the set point, the rate
of change of leaving water temperature, the return water
temperature and the number of compressor stages on.
The control is primarily from leaving water temperature
and the other factors are used as compensation.
2 2 . 2
4 4 . 4
5 5 . 5
6 6 . 7
8 8 . 8
1 0 0 . 0
4
a
2 2 . 2
4 4 . 4
5 5 . 5
6 6 . 7
8 8 . 8
‘00.0
1 0
1 0
1 2
1 6
1 8
6
6
1 6
2 0 . 0
4 0 . 0
5 0 . 0
6 0 . 0
7 0 . 0
8 0 . 0
9 0 . 0
100.0
4
2 0 . 0
4 0 . 0
5 0 . 0
6 0 . 0
4
8
a
SEQUENCE -- On a
for cooling, the
system
starts the initial compressor. The control will randomly
select either circuit A or B. The liquid line solenoid valve
remains closed for 10 seconds after the initial compressor
on that refrigeration circuit starts. This permits a
out cycle at start-up to minimize refrigerant
1 0 0
4
4
1 4
4
7800 ..00 1 6
4
9 0 . 0
1 8
2 0
100.0
18.2
3 6 . 3
4
18.2
3 6 . 3
4 5 . 4
5 4 . 5
63.6
4
a
4 5 . 4 10
5 4 . 5
to the compressor.
the compressor in that refrigeration
1 2
1 4
circuit has run in the 15 minutes before the call for
1 1 0
72.7
cooling, the
After
cycle is bypassed.
72.7
4
4
4
8 1 . 8
2 0
2 2
9 0 . 9
9 0 . 9
00.0
the liquid line solenoid valve opens and
100.0
2 2
4
t
the electronic expansion valve starts to open.
16.6
3 3 . 3
4 1 . 6
5 0 . 0
6 6 . 7
7 5 . 0
9 1 . 6
100.0
4
16.6
4
a
3 3 . 3
4 1 . 6
50.0
a
1 0
1 2
1 6
The electronic expansion valve will open gradually to
provide a controlled start-up to prevent liquid floodback
to the compressor. Also during this period, the oil pres-
sure switch will be bypassed for one minute.
1 0
1 2
1 6
120,
1 6 0
6 6 . 7
7 5 . 0
9 1 . 6
2 2
2 4
6
6
100.0
2 4
As additional cooling is required, the control system
4
4
19.0
3 8 . 0
4 7 . 6
5 7 . 0
6 9 . 0
7 8 . 6
9 0 . 4
100.0
will ramp up through the capacity steps available
the
a
3 8 . 0
4 7 . 6
5 7 . 0
6 9 . 0
7 8 . 6
9 0 . 4
100.0
8
load requirement is satisfied. As capacity steps are added
compressors are brought on line, alternating between the
lead and lag refrigerant circuits. As explained previously,
the speed at which capacity is increased or decreased is
controlled by the temperature deviation from the set
point and the rate of change in the chilled water
temperature.
1 0
1 2
1 6
1 4 0
6
6
2 2
2 4
2 4
NOTE: Circuits and compressors designated from ieft to right when
from front of unit.
4
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LOW WATER TEMPERATURE CUTOUT Move
RUN/ STANDBY switch to STANDBY, then back to
RUN. Restart is automatic.
When the second or lag refrigeration circuit is started,
unless
the circuit will go through a lo-second
the circuit has been operating in the 15 minutes prior to
this start.
AUXILIARY INTERLOCK
condition is corrected.
Automatic restart after
Upon load reduction, the control system will unload
the unit in the reverse order of loading until the capacity
nearly matches the load. Each time the lead compressor is
cycled off, the liquid line solenoid valve and electronic
expansion valve will be closed for 10 seconds prior to
compressor shutdown to clear the cooler of liquid
refrigerant.
OPEN CONTROL CIRCUIT FUSE
Unit will restart automatically.
Replace fuse.
FREEZE PROTECTION
Unit will automatically
restart when leaving water temperature is 6 degrees F
above the leaving water set point.
HIGH-PRESSURE SWITCH, LOSS OF CHARGE
SWITCH, COMPRESSOR DISCHARGE TEM-
PERATURE SWITCH AND OIL SAFETY SWITCH
Unit Shutdown
To stop unit, move the
STANDBY switch to the STANDBY position. Any
refrigeration circuit that is operating at this time will
-- Move the
switch to STANDBY,
continue for 10 seconds to complete the
cycle.
then back to RUN. Unit will restart automatically.
(Lag compressors stop immediately, lead compressors
run for 10 seconds.)
Complete
Stoppage can be caused by any of
the following conditions:
a. general power failure
CONTROLS OPERATION
b. blown fuse in control power feed disconnect
C. open control circuit fuse
Accessing Functions and Subfunctions
Table 5. Refer also to Table 2, which shows the 5 func-
tions (identified by name) and the subfunctions(identified
by number). Table 6 shows the sequence of all the ele-
ments in a subfunction.
d. RUN/STANDBY switch moved to STANDBY
e . freeze protection trip
low flow protection trip
f.
open contacts in chilled water flow switch (optional)
h. open contacts in any auxiliary interlock. (Terminals
TBI-13 and TBJ-14, from factory, are in
Display Functions
SUMMARY DISPLAY
Whenever the keyboard has
not been used for 10 minutes, the display will auto-
matically switch to an alternating summary display. This
display has 4 parts, shown below, which alternate in
continuous rotating sequence.
series with the control switch. Opening the circuit
between these terminals places the unit in STANDBY
mode, just as moving the control switch to STANDBY
would. Code26 will appear as the operating mode
Expansion
Display
TUE
MODE 26
1 STAGES
in the status function display. The unit cannot start
if these contacts are open, and if they open while unit
is running, it will pump down and stop.
TODAY IS TUE, TIME IS
UNIT STANDBY
NUMBER OF STAGES IS 1
Single Circuit Stoppage can be caused by the
following:
2
ALARMS DETECTED
2 ALARMS
STATUS FUNCTION
The status function shows the
lead compressor discharge gas
a. open contacts in
thermostat
current status of alarm (diagnostic) codes. capacity
chilled water set point. all
stages, operating modes,
b. open contacts in loss of charge switch
c. open contacts in oil safety switch
d. open contacts in lead compressor high-pressure switch
Stoppage of one circuit by a safety device action does
not affect the other circuit. Besides stopping com-
pressor(s), all devices listed will also close liquid line
solenoid valve for that circuit.
measured system temperatures, superheat values, pres-
sure switch positions and expansion valve positions.
These subfunctions are defined below. Refer to Table 6
for additional information.
(Alarms) Alarms are messages that one or
more faults have been detected. Each fault is assigned a
code number which is reported with the alarm. (See
Table 7 for code definitions.) The codes indicate failures
that cause the unit to shut down, terminate an option
(such as reset) or result in the use of a default value
as set point.
Lag Compressor Stoppage can be caused by the
following:
a. open contacts in discharge gas thermostat
b. open contacts in high-pressure switch
Up to 3 alarm codes can be stored at once. To view
them in sequence, press
displays and then press
ual alarm displays. Press
to enter the alarm
key to move to the individ-
after a code has been
If stoppage occurs more than once as a result of any
of the above safety devices, determine and correct the
cause before attempting another restart.
played and the meaning of code will scroll across the
screen.
Restart Procedure, after cause for stoppage is
corrected.
When a diagnostic (alarm) code is stored in the display
and the machine automatically resets, the code will be
deleted. Codes for safeties which do not automatically
reset will not be deleted until the problem is corrected
and the machine is switched to STANDBY, then back
GENERAL POWER FAILURE
Unit will restart
automatically when power is restored.
BLOWN FUSE IN POWER FEED DISCONNECT
Replace fuse. Restart is automatic.
to RUN.
on page IO
5
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Table 5
Accessing Functions and Subfunctions
KEYBOARD
ENTRY
DISPLAY
DESCRIPTION
OPERATION
R E S E T
Reset Set Points
To access a function, press the subfunction number and the
function name key. The display will show the subfunction group
Reset Set Point
Reset Limit
To move to the other elements, scroll up or down using the arrow
keys
R S T R
R S P
Reset Ratio
Reset Set Point
When the last element in a subfunction has been displayed, the first
element wilt be repeated
DEMAND
Demand Limit Set Points
To move to the next subfunction, it is not necessary to use the
subfunction number; pressing the function name key will advance
the display through all subfunctions within a function and then back
to the first
Day
of Week Display
S E T
System Set Points
X Alarms Detected
X ALARMS
To move to another function, either depress the function name key
for the desired function (display will show the first subfunction)
or
STAGES
Capacity Stages
Access a particular subfunction by using the subfunction number
and the function name key
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Table 6
Keyboard Directory
QUICK TEST
DISPLAY
STATUS
DISPLAY
COMMENT
KEYBOARD
COMMENT
KEYBOARD ENTRY
Factory/field test of
inputs
Current alarm displays
Alarm 1
INPUTS
X
ALARMS
ALARM
X
LWT
X
Leaving water
temperature
Alarm
Alarm
2
3
ALARM
ALARM
X
X
q
EWT X
Entering water
temperature
Saturated suction temp
El
SSTA
CGTA
SSTB
CGTB
X
MODE
MODE
Current operating
mode displays
circuit
A
X
Compressor suction
gas temp
X
Mode 1
A
STAG ES
STAGE
Capacity stages
Stage number
X
Saturated suction temp
circuit
B
X
Compressor suction
gas temp circuit
X
B
SET
Current operating
set point
Reset temperature
RST X
LCSA
Leaving chilled water
set point
X
X
Loss of charge switch
circuit
A
If unit is in dual set point mode the set point currently in effect
is displayed.
LCSB
Loss of charge switch
circuit
B
Oil pressure switch
circuit
X
A
Leaving water
temperature
Oil pressure switch
Circuit B
X
TEMPS
System temperatures
LWT
X
Cooler leaving water
temp
OUTPUTS
Factory/field test of
outputs
EWT X
Cooler entering water
temp
Circuit
solenoid test
A
liquid line
SLDA
SLDB
X
X
SSTA
CGTA
X
Saturated suction temp
Circuit
solenoid test
B
liquid line
circuit
A
X
Compressor suction
gas temperature
X
Unloader
Unloader
A
B
test
test
circuit
A
UNLB
X
SHA
X
Superheat temp
circuit
A EXV open test
EXVAO
EXVAC
EXVBO
EXVBC
X
A
Circuit
X
X
X
SSTB
CGTB
X
Saturated suction temp
circuit
B
Circuit B EXV open test
Circuit B EXV close test
X
Compressor suction
gas temperature
circuit
B
COMP
Factory/field test of
compressors
SHB
X
Superheat temp
circuit
B
CA1
X
Circuit
test
A
A
compressor
compressor
1
2
Reset temperature
RST X
CA2 X
X
Circuit
test
PRESS
LCSA
Systems pressures
X
Circuit A loss of charge
switch
Circuit B compressor 1
test
X
Circuit
switch
A
oil pressure
CB2 X
B compressor 2
test
LCSB
X
Circuit B loss of charge
switch
X
Circuit
switch
B
oil pressure
During test of compressors, each compressor will start and
run for 10 seconds. Compressor servicevalves and the liquid
line valve must be open. Energize compressor crankcase
heaters for 24 hours prior to performing compressor tests.
ANALOG
System analog values
EXVA
EXVB
X
X
Circuit A EXV valve
position
Circuit B EXV valve
position
END TEST
Leave quick test
7
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Table 6
Keyboard Directory
SERVICE
COMMENT
KEYBOARD ENTRY
DISPLAY
OVRD X
COMMENT
KEYBOARD ENTRY
Entering number of
hours to extend
SCHTYP X
Schedule Type
( ) = entry codes
= inactive, 1 single
set point, 2 dual set
point)
a s follows.
Shows that
ON
OFF
LOG
Define time schedule
period 1
P E R I O D
1
now
again password
protected
Start of occupied time
Return to unoccupied
time
Software version
number
Monday flag
( ) entry codes
(1 = yes, . no)
MON X
Software version
Language
xxx
xxx
TUE X
WED X
THU X
X
Factory configuration
FACT CFG
COMP X
Number of unloaders
(enter number, or. for
zero)
SAT x
SUN X
F F D C F G
UNLS X
RSTP X
Field configuration (
=
entry codes
Sunday flag
Number of unloaders
(enter number)
Reset type
none
1
return water,
space or outside air)
Time periods 2-8 (same elements as
period
Load shed
= disable, 1 = enable)
LDSH X
FLD X
q
Ftuid type
brine)
water,
1
enable
= disable, 1 = enable)
PLDN X
SET POINT
DISPLAY
COMMENT
KEYBOARD ENTRY
System set points
SET POINT
Occupied chilled water
set point
c w s o
x
Unoccupied chilled
set point appears
only when unit is in
dual set point mode
c w s u
x
MSP X
Modified chilled water
set point (read only).
Set point determined
by reset function
R E S E T
Reset set points
Reset set point
Reset
R S P
X
RSTL X
RSTR X
Reset
ratio
Demand limit set points
DEMAND
X
Demand limit set
point
Demand limit set
point 2
q
DL2 X
TIME
DAY 00.00
Current setting
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Table 7
Display Codes
OPERATING MODES
ALARMS
Action
Taken
Control
Reset
Method
Description
Probable Cause
Display
Comp
Al
Al
Failure
Circuit A shut off
Comp shut off
Circuit B shut off
Comp shut off
M a n u a l
M a n u a l
M a n u a l
M a n u a l
High pressure switch trip or high discharge gas temp
switch trip, on when it is not supposed to be on. Wiring
error between electronic control and compressor relay.
Failure
Failure
Failure
C o m p
Comp
B 2
Loss of charge circuit A
Loss of charge circuit B
Circuit A shut off
Circuit B shut off
M a n u a l
M a n u a l
Low refrigerant charge, or loss of charge pressure switch
failure.
Low cooler flow
Unit shut off
M a n u a l
No cooler flow or reverse cooler flow
Low oil pressure circuit A
low oil pressure circuit B
Circuit A shut off
Circuit B shut off
M a n u a l
m a n u a l
Oil pump failure or low oil level, or switch failure.
Freeze protection
Unit shut off
Auto.
Low cooler flow
High suction superheat circuit A Circuit A shut off
High suction superheat circuit B
M a n u a l
M a n u a l
Low charge or EXV failure, or plugged filter drier.
Circuit B shut off
Low suction suoerheat circuit A
Low suction superheat circuit B
Circuit A shut off
M a n u a l
M a n u a l
EXV failure
cooler thermistor error.
Circuit
shut off
Leaving water thermistor failure
Entering water thermistor failure
Cooler thermistor failure circuit A Circuit A shut off
Cooler thermostor failure circuit B Circuit B shut off
Comp thermistor failure circuit A Circuit A shut off
Comp thermistor failure circuit B Circuit B shut off
Unit shut off
Auto.
Auto.
Auto.
Auto.
Auto.
Auto.
Auto.
Thermistor failure, or wiring error, or thermistor not
connected to input terminals.
Use default value
Reset thermistor failure
Stop reset
NOTES:
1. Freeze protection trips at 35 F (1.7 C) for water and 6 degrees F (3.3 degrees C) below set point
for brine units. Resets at 6 degrees above set point.
2. All auto. reset failures that cause the unit to stop will restart the
corrected.
when the error has been
3. All manual reset errors must be reset by moving the control switch to STANDBY then to RUN.
4. Valid resistance range for thermistors is 363,000 ohms to 216 ohms.
9
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(Modes) The operating mode codes are dis-
(Position) The position subfunction displays
played to indicate the operating status of the unit at a
given time. (See Table 7).
the current position of the electronic expansion
in steps:
The modes are explained in the Troubleshooting sec-
tion on page 12.
Fully Open
Operating Position ( 160 Minimum)
Fully Closed, Circuit Shut Down (0)
(Stages) This subfunction displays the capac-
TEST
diagnostic program.
The test operates the Quick Test
When the unit is in STANDBY
ity stage number, from to See Table 4 for compressor
loading sequence to enter the STAGES subfunction,
mode, the test subfunctions will energize the solenoid
valves, unloaders, electronic expansion valves and com-
pressors. The solenoids and unloaders will energize for 3
minutes. The expansion valve will travel to fully open in
one test and to fully closed in the next. The compressors
will energize for 10 seconds. The subfunctions are ex-
plained below. Refer to Table6 for all the elements in
the subfunctions.
depress
and use the
key to display the
stage number.
Displays the status of all inputs.
(Set Point) This subfunction displays the
Tests the outputs from the processor,
except for compressors.
leaving water temperature and the Leaving chilled water
set point. If the unit is programmed for dual set point,
the chilled water set point currently in effect (either
occupied or unoccupied) will be displayed. If reset is in
effect, the unit will be operating to the modified chilled
water set point. This means that the leaving water tem-
perature may not equal the chilled water set point. The
Tests the compressors.
Takes the unit out of Quick Test.
modified
water set point will not be displayed in
the status function. To read the modified chilled water
set point, refer to the Set Point Function section, page
NOTE: The Quick Test energizes the alarm light and
alarm relay. They will remain energized as long as the
unit is in Quick Test.
To enter the set point subfunction, depress
To reach a particular test, enter its subfunction number
then use the
key to display the leaving chilled
key. A
Pressing
and then
to the desired test with the
water set point followed by the leaving water temperature.
.
test can be terminated by pressing
c
l
after a test has started will advance the system to the next
test, whether the current one is operating or has timed
out. Once in the next step, you may start the test by
(Temperature) The temperature subfunction
or advance past it by pressing
.
pressing
displays the readings at temperature sensing thermistors.
c
l
While the unit is in Quick Test, you may access another
display or function by depressing the appropriate keys;
however, the unit will remain in the Quick Test function
To read a temperature, enter
then scroll to
the desired temperature using
the order of the readouts.
key. Table shows
c
l
is entered, or, if the keyboard is not used
until
for
q cl
minutes, the unit will automatically leave the
Quick Test function.
(Pressure) This subfunction displays the
status of the oil pressure and loss of charge switches. The
display will show LOW or
for the oil pressure
switch and LOW or SAFE for loss of charge switch.
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If single
ule has been
selected
Programming
SERVICE FUNCTION
the operator to verify factory configurations and read
or change field configurations. The service subfunctions
are listed below. (See Table 6 for details.)
Functions
The service function allows
set point or inactive
when
depressed
in the schedule function, t h e n
s h o w t h e modified chilled water
the display will
set point.
c. The modified chilled water set point is determined by
the microprocessor as a result of the reset function,
and is displayed for reference only; it cannot be set
or changed by the operator. reset is not in effect, the
The operator must use this subfunction to
log on before performing any other subfunction, a n d
to log off after completing service subfunctions.
modified set point
be the same as either the occu-
pied or unoccupied chilled water set point, according
to how the schedule function has been programmed.
Used to verify software version and
language option.
Displays the reset, reset Limits, and reset
Used to verify factory configurations
(number of compressors).
ratio set points, These set points are not accessible when
reset type has been configured for NONE in the service
funct ion.
to read or change field configuration
SET
3
Displays the demand limit set points.
Displays time of day and day of week.
---
for number of unloaders and reset type and to enable the
machine for load shed,
or brine operation.
4
NOTE: The
key is used to enable or turn on certain
functions; the
key is used to disable thesefunctions.
key is pressed the display will show 00.00.
SCHEDULE FUNCTION
means to
This function provides a
switch the chiller from an
occupied mode to an unoccupied mode. When using the
schedule function, the chilled water pump relay, located
in the unit control box, must be used to switch the chilled
water pump on and off. The chilled water pump relay will
start the chilled water pump but the compressors will not
run until the remote chilled water pump interlock con-
tacts are closed and the leaving chilled water temperature
is above set point. If a remote chilled water pump inter-
lock is not used. the first compressor will start (upon a
for cooling) approximately one minute after the
chilled water pump is turned on.
SET POINT FUNCTION -- Set points are entered
through the keyboard. Set points can be changed within
the upper and lower limits, which are fixed. The ranges
are listed below.
Water Set Point
Water:
4 0 to 70 F (4.4 to 21 C)
Brine (Special Order Units):
for
The schedule function can be programmed
set point. or set operation.
When the schedule is configured for inactive, the
inactive,
15
to
F (-9.4 to 21 C)
si
Set Point
chilled water pump relay remains energized continuously
but is not used since the chiller is usually controlled by
remote chilled water pump interlock contacts.
0 t o 95 F (-17.8 to 35 C)
Reset Limit
0
t o 80 F (-17.8 to 26.7 C)
When the schedule is set for single set point operation,
Reset Ratio
0 t o 100%
Limit Set
Step I Capacity Reduction:
to
the
water pump relay will be energized whenever
the chiller is in the occupied mode regardless of whether
the chiller is running. When the chiller is in unoccupied
mode, the chilled water pump relay
not be energized.
When the schedule is set for dual set point, the chilled
water pump relay will be energized continuously, in both
occupied and unoccupied modes. The occupied mode
places the occupied chilled water set point into effect; the
unoccupied mode places the unoccupied chiller water set
point into effect.
Step 2 Capacity Reduction:
0% to
Set points a re grouped in subfunctions as follows:
Displays chilled water set points.
The schedule consists of from one to 8 occupied time
periods, set by the operator. These time periods can be
flagged to be in effect or not in effect on each day of the
week. The day begins at 00.00 and ends at 24.00. The
machine will be in unoccupied mode unless a scheduled
time period is in effect. If an occupied period is to extend
past midnight, it must be programmed in the following
manner: Occupied period must end at 24:00 hours
(midnight); a new occupied period must be programmed
a. The first value shown is the occupied chilled water
set point.
b. The next value to b e
schedule function h
displayed depends on how the
been programmed. (See below.)
If dual set point has been selected, the next set point
to begin at
hours.
has been pressed will be the unoccupied
after
L - J
The time schedule can be overridden to keep the unit
in the occupied mode for one, 2, 3 or 4 hours on a one-
time basis.
chilled water set point; this will be followed by the
modified chilled water set point.
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If the schedule is holding the machine off when it is
needed, set the schedule for inactive mode until the
schedule can be properly reprogrammed. (See the Sched-
ule Function section of the Installation, Start-Up and
Service Instructions.) The override feature can also
used to temporarily place the unit in occupied mode.
TROUBLESHOOTING
If necessary, review the Flotronic Plus Control System,
Control Sequence, and Controls Operation sections
found in this book. Tables 5 and 6 show how to use the
keyboard/display module to access functions and sub-
functions. (These procedures are also explained in the
Installation,
Service Instructions
then the number of hours to override
. If the unit is in override and
Enter
(1 to
,
c
l
along with examples and details on using the control
features. A copy of the installation instructions should be
kept handy while troubleshooting.)
then press
you wish to cancel it, enter zero hours in the same manner.
Run Mode (28)
Checking Display Codes
To determine how the
machine has been programmed to operate, check the
To enter the MODES subfunction, depress
diagnostic information
mode displays
(
and operating
and use the
key to determine if more than one
mode applies.
If no display appears,
follow the procedures in Troubleshooting, Modules,
page 23. If the display is working, continue as follows:
Do not attempt to bypass, short or modify the
control circuit or electronic boards in any way to
correct a problem. This could result in component
failures or a hazardous operating condition.
1. Note all the alarm codes displayed
2. Note all the operating mode codes displayed
ALARM CODES
The following is a detailed descrip-
3. Note the leaving chilled water temperature set point
in effect and the current leaving water temperature
tion of each alarm code error and the possible cause.
Manual reset of an alarm is accomplished by moving the
RUN/STANDBY switch to STANDBY, then back
to RUN.
If the machine is running, compare the “in effect”
leaving water temperature set point with the current
water temperature. Remember that if reset is in effect,
they may be different because the machine is operating
to the modified chilled water set point. If the current
temperature is equal to the set point but the set point
is not the one desired, recall that if dual set point has
been selected in the schedule function, there are 2 set
points to which the machine can be operating. Check
the programming of the schedule function to see if the
occupied or unoccupied set point should be in effect.
Codes 5 l-54, Compressor Failure
If the DSIO relay
module relay or control relay feedback switch opens
during operation of a compressor, the microprocessor
will detect this and will stop the compressor, energize
the alarm light, and display a code of 5 1 to 54, depending
on the compressor. The compressor will be locked off;
to reset, use the manual reset method.
the lead compressor in a circuit is shut down, all the
other compressors in the circuit will be stopped and
locked off. Only the alarm code for the lead compressor
will be displayed,
The microprocessor has also been programmed to
indicate a compressor failure if the feedback terminal on
OPERATING MODE CODES
Following is an
the
terminal strip receives voltage when the com-
explanation of the operating mode codes:
pressor is not supposed to be on.
Temperature Reset (21)
In this mode, the unit is using
Following are possible causes for this failure:
temperature reset to adjust the set point, and the unit is
controlling to the modified set point. This means that the
leaving water temperature may not equal the chilled water
set point. The set point can be modified based on return
water, outside air temperature or space temperature.
Switch Open
The high-pressure switch
for each compressor is wired in series with the 24-volt
power that energizes the compressor control relay. If the
high-pressure switch opens during operation the com-
pressor will stop and this will be detected by the micro-
processor through the feedback terminals.
Demand Limit (22)
This indicates that the capacity of
the unit is being limited by the demand limit control
option. The unit may not be able to produce the desired
leaving water temperature because the unit may not load
to full capacity.
Gas Thermostat
The discharge gas thermo-
stat switch in each compressor is also wired in series with
the 24-volt power that energizes the control relay (CR).
If the switch opens during operation of the compressor,
the compressor will be stopped and the failure will be
detected through the feedback terminals.
Control (24) -- If this option is in effect and
the cooler water temperature is warm, extra stages will
not be added if the water temperature leaving the cooler is
decreasing faster than
F (0.6 C) per minute.
Module Failure
If a DSIO relay module relay
fails open or closed, the microprocessor will detect this
and lock the compressor off and indicate an error.
Standby (26) The unit is being held in the standby
mode either because the RUN /STANDBY switch is
or a set of relay contacts in series with the
STANDBY switch is open (contacts wired between
Wiring Errors
If a wiring error exists causing the CR
or feedback switch not to function properly, the
will indicate an error.
terminals
and
Unoccupied Mode (27)
In dual set point schedule, this
I f t h e h a r d w a r e t h a t
mode means the machine is operating to the unoccupied
set point. In single set point schedule, this mode shuts
down the unit in the same manner as “Unit Standby.”
monitors the feedback switch fails or the processor fails
to energize the relay module relay to ON, an error may
be indicated.
12
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NOTE: The control does not detect circuit breaker
failures. If a circuit
trips on the lead compressor
in a circuit, a
pressure failure
be indicated;
be indicated.
on the other compressors, no failure
Shut off the main
power to the unit. Turn on control power, then step
through the Quick Test to the proper compressor number
(i.e., failure code
is
Next, energize the
step. If the step works correctly, then the failure code
is due to:
.
l
l
back wire from
strip to
strip
l
Ground wire and
points on The
feeds reversed on one or more
ground wire
terminals 2, 4, 6 and 8. Feeds
compressors Al,
A2, and connect to pins I, 3, 5 and 7.
Fig.
3
Compressor Al Control Wiring (Typical)
The processor closes the contacts between 255 ter-
minals 12 and I to start the (See Fig. 3.) The
safeties shown to the right of 2.15 must be closed for
Code 63 and 64, Low Oil Pressure
A low oil pressure
power to reach the compressor
the feedback input (terminal
relay (CR 1) and
switch is installed on the lead compressor in each circuit.
If the switch opens during operation of the compressor,
Failure of power to terminal
when contacts
a code 5 alarm.
all the compressors in the circuit
light
be shut off, the alarm
be energized and the appropriate display code
I and I2 should be
wilt
Terminal 2 on 293 is the other leg the compressor Al
shown. The switch will be bypassed for one minute during
start-up and for 45 seconds during normal operation. The
manual reset method must be used to reset this safety.
feedback channel. It is connected to the
ground.
Possible causes for failure are:
of’ Oil
If the oil pressure is below 5
6.9 kpa), the switch will open.
Code 59 and 60, Loss of Refrigerant Charge
A
psig (34.5
charge switch is connected to the high-pressure side of
the refrigerant system. The microprocessor monitors this
switch directly; if it opens, all the compressors in the
If the switch fails open, a failure will be
indicated.
circuit will be locked off, the alarm
be energized and
is
running.
the display code will appear when the alarm display is
accessed. To reset, use the manual reset method (move
If a wiring error exists that causes an
wiring
open circuit, an error will occur.
the RUN/STANDBY switch to
to RUN).
Following are some possible causes for this alarm:
then back
If the hardware on the
processor module fails in a manner that the switch cannot
be read properly, an error may be indicated.
If the system refrigerant
low, the microprocessor will detect this
Code 65, Cooler Freeze Protection If the leaving water
charge
temperature is below 35 F (1.7
for a water chiller or
the set point for brine applications,
be stopped. This safety auto-
through the switch and indicate the error.
Failure If the switch open, the micro-
processor will detect this and indicate an error.
is
(3.3
compressors
matically reset when the water temperature is 6 F (3.3 C)
above the set point.
Wiring
If there is a wiring error that causes an
open circuit, the microprocessor
switch and indicate an error.
treat this as an open
The causes for this failure are usually due to low cooler
or extremely rapid load changes.
Code 66 and 67, High Suction Superheat
processor contains the following and
all the compressors in the circuit will be stopped:
Suction superheat is greater than 75 F (4f.7 C), and
saturated
these 2 conditions have been true for more than5 minutes.
To reset this, use the manual reset method.
C a uses for this failure are:
Failure
If the hardware in the pro-
The micro-
is satisfied,
cessor module fails in a manner that the switch cannot
be read properly, an error may be indicated.
Code 61, No Cooler
tains logic that
The microprocessor con-
the cooler against loss of cooler
suction is
than 55 F (12.8
and
cooler entering and leaving water temperature
sensors are used for this purpose. The leaving thermistor
is located in the leaving water
and the entering
sensor is located in the first cooler baffle space in close
proximity to the cooler tubes as shown in Fig. 4. When
A low refrigerant charge
there is no cooler water
operating, the leaving water temperature thermistor
and the compressors are
not allow the correct amount of refrigerant to be fed to
the evaporator, which
result in a high superheat.
If the liquid line filter drier
indicate no temperature change. But the temperature of
the entering water will drop rapidly and the entering
water thermistor will detect this. When the entering water
Filter
becomes plugged, it can result in not enough refrigerant
being fed to the evaporator, which results in a high super-
heat failure.
temperature drops to 5 (2.8
below the leaving water
temperature,
the compressors stop and code
no. 61 will be displayed. To correct, use manual reset
method (after cooler water Row is resumed).
Failure
If the EXV fails to open enough to feed
the proper amount of refrigerant, the error will occur.
The error will be caused either by no
flow or
Failure
hardware that controls the
not move.
the
fails, the
module
will
if the water is flowing in the wrong direction through the
cooler or if the thermistors have been interchanged.
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LEAVING
WATER
SUCTION
\
INLET
CONNECTION
COOLER TUBE
THERMISTOR..
ENTERING COOLER
WATER
SENSOR
Fig. 4
Cooler Sensor Locations
Thermistors mis-located or out of
Quick Test
The Quick Test feature allows the service
calibration.
Code 68 and 69, Low Suction Superheat
ing logic is satisfied, then all the compressors on the
circuit be stopped.
Suction superheat is equal to 0°F
technician to individually test all the inputs and outputs
of the control system.
if the follow-
The test function operates the Quick Test diagnostic
program. When the unit is in STANDBY mode, the test
subfunctions will energize the solenoid valves, unloaders,
electronic expansion valves and compressors. The
solenoids and unloaders will energize for 3 minutes. The
or the satu-
rated suction is greater than 58 F (14.4 C) and either
condition has been true for more than 5 minutes.
electronic expansion valve
travel to fully open in one
Possible causes for this failure are a stuck electronic
expansion valve or thermistors mis-located or out of
calibration.
test and to fully closed in the next. The compressors
energize for 10 seconds. The subfunctions are explained
below. Refer to Table 6 for all the elements in the
subfunctions.
To reset, use the manual reset method.
Code 71 to 81, Thermistor Failure
If the measured
F (-51 C)
temperature of a thermistor is less than
NOTE: The Quick Test energizes the alarm light and
alarm relay. They will remain energized as long as the unit
is in Quick Test.
(363,000 ohms) or greater than 240 F (116 C) (2 16 ohms),
the appropriate sensor error code will be displayed and
the unit
be stopped. The thermistor failures will
To reach a particular test, enter its subfunction number
automatically reset. The following is a summary of
possible causes.
and then scroll to the desired test with the
test can be terminated by pressing
key. A
Pressing
Thermistor Failure
A shorted or open circuit ther-
mistor will cause the failure.
.
c
l
Wiving Failure
the failure.
A shorted or open circuit will cause
after a test has started will advance the system to the
next test, whether the current one is operating or has
timed out. Once in the next step, you may start the test
Module
If the circuitry in the pro-
cessor module fails, the error could occur.
by pressing
or advance past it by pressing
.
NOTE: The reset thermistor is an optional thermistor
and is only used with outside or space temperature reset.
It will only be read by the processor if the unit is con-
figured for outside or space temperature reset.
The absence of a thermistor failure does not necessarily
mean that a thermistor is accurate. To determine
accuracy, the reading must be compared with a measure-
ment of the actual temperature to which the thermistor
probe is exposed.
c
l
c
l
While the unit is in Quick Test, you may access another
display or function by depressing the appropriate keys;
however, the unit will remain in the Quick Test func-
tion until
is entered, or, if the keyboard is
not used for 10 minutes, the unit will automatically leave
the Quick Test function. See the following example:
14
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KEYBOARD
ENTRY
Loss of charge and oil pressure switch tests show
if the switch is and NRM or SAFE if the switch is
DISPLAY
RESPONSE
COMMENTS
I
closed. The input channel can be tested by disconnecting
the switch and using a jumper to simulate a closed or open
circuit. (See Fig. 5.)
Note that the switch is read by the processor period-
ically, not continuously. When the switch position is
changed, it may take a few seconds before the display
changes.
3
COMP
Factory field test of compressors
subfunction of test function
q u
OFF
Circuit A, compressor test
CA1 ON
Pressing
starts the test; when the
q
compressor should be running the
display shows CA1 on
OFF
C A 2 O F F
END TEST
If the test is allowed to time out, the
T h e
subfunction will energize the control
display will show
off
outputs except for the compressor control outputs. (See
Fig. 6.)
The liquid line solenoid and unloader solenoid tests
q
Pressing the down arrow key advances
the system to circuit A, compressor 2 test
If no other test
desired, exit quick test
will energize the output when
is pressed. It will
key is pressed or
remain energized until either the
10 minutes have elapsed. When the processor energizes
the output it will display the word ON on the right
side of the display.
The EXV open and close tests drive the EXV fully open
or fully closed. See The EXV Checkout Procedure for
more information. The display will read either zero steps
open or 760 steps open.
Refer to Fig.
and 7 for specific control wiring. Each
module in a panel is numbered
strip is labeled
Each terminal
The terminal strip on the
machine schematic combines the module and strip
For example,
is terminal strip
on
numbers.
subfunction energizes the compressor
T h e
module 2. The module numbers can be found on the com-
ponent arrangement label.
control relays for 10 seconds and displays the compressor
status feedback.
The liquid line solenoid in the same circuit will ener-
gize for 10 seconds and the EXV will open 180 steps,
then close.
When control power reaches the compressor control
relay it also reaches the feedback terminal on terminal
strip 233 (see Fig. 7). When this occurs the display
switch from OFF to UN. If the display changes but the
compressor does not start, check the control relay,
compressor circuit breaker, interconnecting
wiring, and the compressor motor.
T h e
subfunction checks the thermistor and
switch inputs. The thermistor tests display the tempera-
ture that the thermistor is reading. If the display and the
actual temperature do not match, the thermistor and the
input channel can each be checked.
To check the thermistor, disconnect its leads from the
terminal (the entire connector can be pulled from
the
by pulling the connector to the left). Read the
resistance of the thermistor, then find the corresponding
temperature in Table 8.
This temperature should match the actual temperature
to which the thermistor is exposed.
The thermistor can be checked while connected to the
processor by measuring the voltage across its terminals
and finding the corresponding temperature in Table 8.
This method can only be used if it is certain that the
processor circuits are putting out the correct voltage. If
there is any doubt, the thermistor should be checked by
If the display does not change, check the discharge gas
thermostat, high-pressure switch, condenser fan overload
(on
if used), continuity across the
terminals
and interconnecting wiring.
To protect the compressors from repeated cycling, a
delay of one minute is required before the same com-
pressor is retested.
the resistance method.
The input channel can be tested by removing the
thermistor from the terminals and attaching a fixed
resistor with a value between 40,000 ohms and 400 ohms.
Refer to Table 8 and find the temperature that cor-
responds to that resistance; this temperature should
The
subfunctions take the unit out of the
and the display will
q
Quick Test mode. Press
show
TEST; press
and the display blinks and
c
l
appear in the Quick Test display.
then shows END TEST again.
15
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P R O C E S S O R
TTHH EE SE CONTACTSO P E R A T E S
Fig. 5
Compressor 24-V Control Circuit Wiring
(Simplified)
24V FEED
24V NEUTRAL
2 4 v
F E E D
N E U T R A L
TERM
STRIP
U N L O A D E R C K T .
A
UNLOADER CKT.
LIQUID
SOLENOID CKT. A
CIRCUIT
LINE
SOLENOID CKT.
LOSS OF
C H A R G E
A
Fig.
Pressure Feedback Circuit Wiring
(Simplified)
Fig.
7
Auxiliary Components 24-V Control
Circuit Wiring (Simplified)
1 6
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Table
Temperature
Resistance and Voltage
TEMPERATURE
VOLTAGE
DROP
VOL T AGE
DROP( V)
RESI STANCE
(OHMS)
RESISTANCE
8076. 1
7867. 7
7665. 1
7468. 3
7277. 1
7091. 2
69106
6735. 1
6564. 4
- 25. 0
- 24. 0
4. 821
4. 818
3. 464
3. 437
3. 409
3. 382
3. 353
3. 323
3. 295
3, 267
3. 238
58. 0
9 4 7 0 7 . 1
- 23. 0
- 22. 0
- 21. 0
- 20. 0
- 19. 0
- 18. 0
- 17. 0
4. 814
4 . 8 0 6
4. 800
4. 793
4. 786
4. 779
4. 772
4. 764
88448.9
8 5 4 8 5 . 5
8 2 6 2 7 . 2
7 9 8 7 0 . 6
61. 0
6 2 0
63. 0
644. 0
65. 0
66. 0
67. 0
68. 0
69. 0
7 7 2 1 2 . 0
7 4 6 4 7 . 9
72175. 1
- 16. 0
- 15. 0
6398. 6
6237. 5
4. 757
4. 749
4. 740
6 9 7 9 0 . 3
6 7 4 9 0 . 4
3. 184
3, 152
3. 123
3. 093
3. 064
- 14. 0
- 13. 0
6080. 8
5928. 6
5780. 6
5636. 8
5497. 0
5361. 2
5229. 1
5100. 8
4976. 0
70. 0
6 3 1 3 3 . 3
6 1 0 7 0 . 3
59080. 6
57161. 7
5 5 3 1 0 . 9
5 3 5 2 5 . 8
5 1 8 0 4 . 0
50143. 2
48541. 1
4 6 9 9 5 . 6
4 5 5 0 4 . 7
4 4 0 6 6 . 3
4 2 6 7 8 . 5
4 1 3 3 9 . 3
40047. 1
38800. 0
3 7 5 9 6 . 4
36434. 7
35313. 3
34230. 7
3 3 1 8 5 . 4
3 2 1 7 6 . 2
31201. 5
30260. 1
2 9 3 5 0 . 9
2 8 4 7 2 . 5
2 7 6 2 3 . 8
26803. 7
2 6 0 1 1 . 2
25245. 1
2 4 5 0 4 . 6
2 3 7 8 8 . 7
2 3 0 9 6 . 4
2 2 4 2 6 . 9
2 1 7 7 9 . 3
21152. 8
20546. 7
1 9 9 6 0 . 2
19392. 5
1 8 8 4 3 . 0
18311. 0
17795. 8
1 7 2 9 7 . 0
16813. 8
16345. 7
15892. 2
15452. 7
15026. 7
14613. 9
14213. 6
13825. 5
13449. 2
13084. 2
12730. 1
12386. 6
120533
11730. 0
- 12. 0
- 11. 0
- 10. 0
4. 734
4. 724
4. 715
73. 13
74. 0
4. 705
4 . 6 9 6
4. 688
4 . 6 7 6
4 . 6 6 6
4. 657
3. 005
2. 977
2. 947
2. 917
2. 884
2 . 8 5 7
2. 827
2. 797
- 8. 0
- 7. 0
75. 0
76. 0
77. 0
76. 0
7 9 . 0
80. 0
87. 0
82. 0
83. 0
84. 0
85. 0
- 6. 0
- 5. 0
- 4. 0
4736. 9
- 3. 0
- 2. 0
- 1. 0
0. 0
1. 0
2. 0
3. 0
4. 0
5. 0
6. 0
7. 0
4. 648
4. 636
4. 624
4. 613
4. 602
4. 592
4. 579
4. 567
4 . 5 5 4
4 . 5 4 0
4. 527
4511. 1
4402. 9
4297. 7
4195. 5
2. 766
2. 738
2. 679
2. 650
2. 622
2. 593
2. 563
2. 533
2. 505
2. 476
2. 447
2. 417
2. 388
2. 360
2. 332
2. 305
2. 277
2. 251
2. 217
3999. 6
3905. 7
3814. 4
3725. 8
3639. 5
3555. 7
87. 0
89. 0
90. 0
91. 0
92. 0
93. 0
94. 0
95. 0
96. 0
97. 0
8. 0
9. 0
4. 514
4. 501
4. 487
4 . 4 7 2
4. 457
4. 442
4. 427
4. 413
4. 397
4. 381
4 . 3 6 6
3474. 2
3395. 0
3318. 0
3243. 1
3170. 3
10. 0
11. 0
12. 0
13. 0
14. 0
15. 0
16. 0
17. 0
18. 0
19. 0
20. 0
3099. 4
3030. 5
2963. 5
2898. 4
2834. 9
2773. 2
2713. 1
2654. 7
2597. 8
2542. 3
98. 0
99. 0
100. 0
101. 0
102. 0
103. 0
104. 0
105. 0
106. 0
107. 0
108. 0
109. 0
110. 0
111. 0
112. 0
113. 0
114. 0
4. 348
4. 330
4 . 3 1 3
4. 295
4. 278
4. 258
4. 241
4. 223
4. 202
2. 162
2. 136
2. 107
2. 080
2. 053
2. 028
2. 001
1. 973
1. 946
1. 919
1. 897
1. 870
21. 0
22. 0
23. 0
24. 0
25. 0
26. 0
27. 0
28. 0
29. 0
30. 0
31. 0
32. 0
33. 0
34. 0
35. 0
36. 0
37. 0
38. 0
39. 0
40. 0
41. 0
42. 0
43. 0
44. 0
45. 0
46. 0
47. 0
48. 0
49. 0
50. 0
51. 0
52. 0
53. 0
54. 0
55. 0
56. 0
57. 0
2488. 3
2435. 8
2384. 5
2334. 6
2285. 9
2238. 5
2192. 2
2147. 0
4. 165
4. 145
4. 125
4. 103
4 . 0 8 2
4. 059
4. 037
4. 017
3. 994
3. 968
3. 948
3. 927
3 . 9 0 2
3. 878
3. 854
3. 828
3. 805
3. 781
3. 757
3. 729
3. 705
3. 679
3. 653
3. 627
3. 600
3. 575
3. 547
3. 520
3. 493
115. 0
116. 0
1. 846
1. 822
1. 792
1. 771
1. 748
1. 724
1. 702
1. 676
2103. 0
2060. 0
2018. 0
1977. 0
1936. 9
1897. 8
1859. 5
1822. 1
117. 0
118. 0
119. 0
120. 0
121. 0
122. 0
123. 0
124. 0
125. 0
126. 0
127. 0
1. 653
1. 630
1. 607
I . 585
1. 562
I . 538
1. 517
1. 496
1. 474
1. 453
1. 431
1785. 5
1749. 7
1714. 7
1680. 4
1646. 8
1613. 8
128. 0
129. 0
11111. 5
10815. 8
10528. 7
1581. 6
1550. 0
1519. 0
1488. 6
1458. 8
1429. 6
1400. 9
1372. 7
1345. 1
1318. 0
1291. 3
1265. 2
130. 0
131. 0
132. 0
133. 0
134. 0
135. 0
136. 0
137. 0
138. 0
139. 0
140. 0
10250. 0
9979. 3
9 7 1 6 . 5
9 4 6 1 . 3
9213. 4
8972. 6
8738. 6
8511. 4
8290. 6
1. 389
1. 369
1. 327
1. 308
1. 291
1
7
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Table
Thermistor Temperature
Resistance and Voltage
T E MP E RAT URE
RESISTANCE
T E MP E RAT URE
VOL T AGE
VOL T AGE
4. 8961
4. 8892
4. 88177
4. 874
4. 86577
4. 85709
4. 84793
3. 38739
3. 3366
3. 2853
3. 23369
7. 499
7 . 1 6 1
6 . 8 4
- 39
- 38
- 37
- 36
- 35
- 34
- 33
- 32
- 3 1
- 30
4
157. 44
1 4 7 . 4 1
138. 09
1 2 9 . 4 1
121. 33
6. 5358
6. 246
5. 971
5. 7095
5. 461
20
3. 12913
3. 07641
3. 02348
2. 97044
22
23
24
25
26
27
28
29
4. 82808
4. 81736
4. 80608
4. 79421
4. 78151
4. 76863
4. 75488
4. 74046
4. 72534
4. 7095
100. 26
94. 165
88. 48
5 . 2 2 5
2. 86384
2. 81049
2. 75717
2. 70394
2. 65082
2. 59787
2. 54514
2. 4927
4 . 7 8 6 1
4. 5825
4. 3887
4. 2042
4. 0284
3. 8609
3. 7013
3. 5492
3 . 4 0 4 1
3. 2657
3. 1338
3. 0078
2. 8876
2. 7728
2. 6632
2. 5585
2. 4585
2. 3629
2. 2716
2. 1842
2. 1007
2. 0208
1. 9444
78. 125
73. 58
69. 25
65. 205
61. 42
57. 875
54. 555
51. 45
48. 536
45. 807
43. 247
40. 845
38. 592
36. 476
34. 489
3 2 . 6 2 1
30. 866
29. 216
27. 633
26. 202
24. 827
23. 532
22. 313
21. 163
20. 079
19. 058
a. 094
- 27
- 26
- 25
- 24
3 1
32
33
34
35
36
37
38
39
40
4 1
42
43
44
45
46
47
48
49
- 23
- 22
- 2 1
- 20
4. 6929
2. 44053
2. 38871
2. 33733
4. 67557
4. 65743
4. 6365
4. 61873
2. 23582
2. 08738
4. 57663
4. 55426
4. 53099
4. 50678
- 15
- 63
1. 94433
I
4. 45556
4. 42794
4. 40044
4. 37141
4. 34138
4. 31036
4. 27829
4. 24521
4. 21115
- 10
- 9
- a
- 7
- 6
- 5
- 4
- 3
- 2
- 3
0
1. 76302
1. 71947
1. 67672
1. 63474
1. 8012
1. 7342
1. 67
1. 6085
1. 5495
1 . 4 9 3 1
7 . 4 3 9
1 . 3 8 7 1
1. 3374
1 . 2 8 9 7
1. 2439
1. 2
1. 1579
1. 1175
1. 0786
1. 0414
1. 0056
5 7
52
53
54
55
56
57
58
1. 55306
1. 51333
1. 47449
4. 73993
0279
17. 184
16. 325
15. 515
14. 749
14. 026
13. 342
12. 696
1
4. 06471
4. 0256
3. 98557
3. 94454
3. 90262
3. 85979
3. 816
1 . 3 9 9 1 1
1. 36264
2
3
4
60
6 1
62
63
64
65
66
67
68
69
1. 25786
1. 22454
1 . 1 9 2
7
a
9
11. 506
10. 959
10. 441
9. 9495
9. 485
3. 77142
3. 726
1. 12916
1. 09887
3. 67969
3. 63271
3. 58496
3. 53653
3. 48742
3. 43771
1 1
1 2
9. 0445
1. 04046
1 4
1 5
a. 237
7. 8555
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Electronic Expansion
CHECKOUT
diagnose and correct
of EXV operation, see
to
problems, For an
2
Step 1
Check EXV Driver Outputs
output signals at appropriate terminals on
module (Fig. 8) as
Connect positive test
to terminal 1 on EXV driver.
Set meter for approximately 20
Enter outputs sub-
, then
function of test function by pressing
advance to EXVA Open Quick Test by pressing
times. Press . The driver should drive the EXV
EXV A
open. During the next several seconds connect the nega-
tive test lead to pins 2. 3, 4 and 5 in succession. Voltage
should rise and fall at each pin. If it remains constant at a
voltage or at zero volts, remove the connector to the valve
and recheck. Press
to reach the EXV A
Quick
Fig.
EXV
Connections to
Test. If a problem still exists, replace the EXV
If
EXV Driver Module
the voltage reading is correct, the expansion valve should
be checked. Next, text
Connect the positive test
2. Check for continuity and tight connection at
pin
lead to pin 7 and the negative to pin
sion during the EXVB Quick Test.
1 in succes-
3. Check plug connections at driver and at
EXV connections are not crossed.
He sure
Step 2
Check EXV Wiring
Check wiring to elec-
tronic expansion valves from terminal strip on EXV
Step 3
Check Resistance of EXV Motor Windings
at terminal and check resistance
lead (red wire, terminal and remain-
C. and E (see Fig. 8). Resistance should
-2 ohms.
driver (Fig.
Remove
Check color coding and wire connections. Make sure
they are connected to correct terminals at driver and
EXV plug
between
ing leads A,
be 25 ohms
1 9
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- M U F F L E R S
MUFFLERS
COMPRESSORS
COMPRESSORS
Fig. 9
Thermistor Locations
Step
4
Check Thermistors That Control EXV
3. Remove screws holding top cover of EXV. Carefully
Check thermistors that control processor output voltage
remove top cover, using caution to avoid damage to
the motor leads. If EXV plug was disconnected during
this process, reconnect it after the cover is removed.
pulses to
Circuit thermistors are
location.
Circuit A thermistors are T5 and T7.
and
Refer to Fig. 9 for
4. Enter appropriate EXV Quick Test step for EVXA or
the temperature subfunction of the status function
EqXVB in the outputs subfunction of the test function
to determine if thermistors are reading
Press
to initiate test. With cover
correctly.
lifted off the EXV valve body, observe operation of
valve motor and lead screw. The motor should turn
2. Check thermistor calibration at known temperature
by measuring actual resistance and comparing value
in the
direction and the lead screw should
move down into the motor hub until the valve is fully
closed or fully open depending on whether you initiate
the open or close test step for that valve. Lead screw
movement should be smooth and uniform from fully
open to fully closed position, or from fully closed to
fully open.
measured with
listed in Table 8.
3. Make sure that thermistor leads are connected to
proper pin terminals at 157 terminal strip on processor
module and that thermistor probes are located in
proper position in refrigerant circuit (Fig. 9).
When above checks have been completed, actual
operation of EXV can be checked by using procedures
outlined in Step 5.
If valve is properly connected to processor and receiv-
ing correct signals, yet does not operate as described
above, the valve
be replaced.
The operation of the EXV valve can also be checked
without removing the top cover. This method depends on
the operator’s skill in determining whether or not the
valve is moving, To use this method, initiate the Quick
Test to open the valve. Immediately grasp the EXV valve
body with the hand. As the valve drives open, a soft,
smooth pulse will be felt for approximately 26 seconds
as the valve travels from fully closed to fully open. When
the valve reaches the end of its opening stroke, a hard
pulse will be felt momentarily. Drive the valve closed and
Step 5
Check Operation of the EXV
Use following
procedure to check actual operation ofelectronic expan-
sion valves.
Close liquid line service valve for
to be checked
and run through the Quick Test step (in subfunction
3 of test function) for the lead compressor in that
circuit to pump down the
side of the system.
Repeat test step 3 times to ensure that all refrigerant
has been pumped from low side.
a
soft, smooth pulse will be felt for the 26 seconds necessary
for the valve to travel from fully open to fully closed.
When the valve reaches the end of its stroke, a hard pulse
NOTE: Be sure to allow compressors to run full
seconds at each step.
will again be
as the valve overdrives by 50 steps. The
valve should be driven through at least 2 complete cycles
to be sure it is operating properly. If a hard pulse is felt
for the 26 second duration, the valve is not moving and
should be replaced.
2. Turn OFF compressor circuit breaker(s). Close com-
pressor service valves and vent any remaining refrig-
erant from low side of system.
20
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The EXV test can be repeated
by pressing
phase condition (liquid and vapor). To control
flow for different operating conditions, piston
moves up and down over orifice, thereby changing
size. Piston is moved by a linear stepper motor. Stepper
motor moves in increments and is controlled directly by
processor module. As stepper motor rotates, motion is
may be due to out-of-calibration
mittent connections between processor board
or inter-
flow
into
movement by lead screw. Through
screws, discrete steps of
and
plug. Recheck all wiring
motor and
voltage signals.
obtained. The large number of steps and long
control of refrigerant
Other possible causes of improper
control could be restrictions in liquid line. Check
plugged filter drier(s), stuck liquid line solenoid
or restricted metering slots in the EXV. Formation of ice
or frost on lower body of electronic expansion valve is
one symptom of restricted metering slots. Clean or
replace valve if necessary.
NOTE: Frosting of valve is normal during compressor
Quick Test steps and at initial start-up. Frost should
dissipate after 5 to minutes operation of a system that is
operating properly. If valve is to be replaced, wrap valve
with a wet cloth to prevent excessive heat from damaging
internal components.
EXV OPERATION
These valves control the flow of
into the cooler. They are operated by
degrees F of superheat
B e c a u s e
module, it is
to track
During
start-up,
the
to maintain
initial start-up, EXV is
position is tracked by processor by constantly
amount of valve
The processor keeps track of the EXV position by
counting the number of open and closed it has
to each valve. has no direct feedback of valve
position. Whenever the unit is switched from STANDBY
between the cooler entering refrigerant thermistor and the
lead compressor entering gas thermistor (located between
the compressor motor and the cylinders). There is one
EXV per circuit. A cutaway drawing of valve is shown
in Fig.
to
both valves
be
This
the
processor will send enough closing pulses to the
to
move it from
position counter to zero.
open to fully closed and then reset the
The EXV open Quick Tests will send enough pulses to
the valve to drive it from fully closed to fully open. The
position of the
on the number of
at the start of the test has no effect
sent.
In the
send
the EXV close Quick Tests will
valve to drive it from fully
open to fully closed,
When the EXV opens, the metering slots are not
uncovered until step
This is fully closed position
when
circuit is operating. The fully open position is
760
T h e
subfunction shows the EXV valve
positions. They should
constantly while the unit
operates. If a
should stop moving for any reason
4
-STEPPER MOTOR
(mechanical
electrical) other than a processor or
3 -LEAD SCREW
thermistor failure. the processor will continue to attempt
to open
the calculated valve position reaches
or (fully open) it will remain there. If the EXV posi-
close the valve to correct the superheat. Once
2
-PISTON
(fully closed)
-ORIFICE ASSEMBLY
tion reading remains at 160 or 760 and the cooler and
compressor refrigerant thermistor displays are reading
the measured temperature correctly, the EXV is not
moving. Follow the EXV checkout procedure to deter-
mine the cause.
Fig.
Expansion Valve
The EXV is also used to limit cooler suction tem-
perature to 55 F (13 C). This makes it possible for the
chiller to start at higher cooler water temperatures with-
out overloading compressor. This is commonly referred
High-pressure liquid refrigerant enters valve through
bottom. A series of calibrated
have been machined
in side of orifice assembly. As refrigerant passes through
orifice, pressure drops and refrigerant changes to a
to as MOP (maximum operating pressure).
21
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SENSOR REPLACEMENT
(Compressor and Cooler)
T2, T5, T6, T7,
Thermistors
All thermistors are identical in their
temperature vs resistance performance. Resistance at
various temperatures are listed in Table 8.
Sensors are installed directly in refrigerant or water
circuit. Relieve all refrigerant pressure or drain water
before removing.
LOCATION -- General location of thermistor sensors
are shown in Fig. 9.
Cooler Leaving Water Sensor,
is located in the leav-
ing water nozzle. The probe is immersed directly in the
water. All thermistor connections are made through a
coupling (Fig. I I). Actual location is shown in
Fig. 4.
Proceed as follows (refer to Fig. I I):
Remove and discard original sensor and coupling.
IMPORTANT: Do not disassemble new
install as received.
Cooler Entering Water Sensor, T2, is located in the cooler
shell in first baffle space, near to tube bundle. Actual
location is shown in Fig. 4.
Cooler Saturated Suction Temperature Sensors,
2. Apply pipe sealant to I
NPT threads on replace-
and
ment coupling and install in place of original. Do not
use packing nut to tighten coupling; this would
damage ferrules (see Fig. I I
are located next to refrigerant inlet in cooler head.
Thermistors are immersed directly into refrigerant.
Typical location is shown in Fig. 4.
Compressor Suction Gas Temperature Sensors, T7 and
are located in lead compressor in each circuit in a
suction passage between motor and cylinders, above
oil pump.
3. Insert new sensor in coupling body to its
depth.
Hand tighten packing nut to position ferrules, then
finish tightening
turns with a suitable
Ferrules are now attached to sensor, which can be
withdrawn from coupling for unit servicing.
FERRULES
INSIDE
COUPLING
/ASSEMBLY
FERRULES
SENSOR
CABLE ASSEMBLY
C O U P L I N G
B O D Y
Fig. 11
Thermistor (Compressor and Cooler)
22
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The green LED should always be blinking
Modules
on; it indicates that the modules are communicating
properly.
a green LED is not blinking, check
the red LED is normal, check the module address
Turn controller power off before servicing
switches. See Fig. 9. The proper addresses are:
controls. This is to ensure safety and prevent damage
to the controller.
(Processor Module)
(Relay Module)
32
Driver Module) -- 50
indicate a communication failure, check
PROCESSOR MODULE
RELAY MODULE
LOW-VOLTAGE
EXV DRIVER
and modules
the
the
connection is
the
module for proper seating.
and the condition per-
MODULE
The
sists,
module.
perform continuous diagnostic evaluations of the condi-
tion of the hardware. Proper operation of these modules
only a
check the
module indicates a communication
plug on that module for proper
is indicated by
surface of the
of the PSIO.
(light emitting diodes) on the front
and on the top horizontal surface
seating. a good connection is assured and the condition
persists.
the
All
operating
rests in the
that controls
Red LED:
(processor
the
at a 3 to 5 second rate indicates
the unit. This
monitors conditions through input
proper operation
and output ports and
voltage
module and module).
Lit
indicates a problem requiring replace-
The machine
processor through
communicates with the micro-
module
ment of the module
module). Communication between
other modules is accomplished by a
and the
bus.
to module.
2, Each
indicates the power
be checked.
If there is no input power, check fuses. If fuse is bad, check
for shorted secondary of transformer, or for bad module.
These 3 wires run in
from
Each module in a panel is numbered
terminal strip on a module is
terminal strip number on the machine schematic com-
Green LED: (On a
the connectors. The other green LED on the
module indicates external communications, when used.)
this the green LED closest to
bines the module and strip numbers. For example,
terminal strip on module 2. The module numbers can
be found on the component arrangement label.
is
ADDRESS
SELECTOR
Fig.
Module Address Selector Switch
Locations
2 3
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On the sensor bus terminal strips, terminal of the
module is connected to terminal 1 of each of the
other modules; terminals 2 and 3 are connected in the
same manner. (See Fig. 13.) If a terminal 2 wire is con-
nected to terminal 1, the system will not work.
Low-Voltage Relay Module (DSIO) (Fig. 15.)
on strip
are applied
as an ON signal,
arc
inputs
- -
OFF).
24
2
in
is read
a channel it is
as an OFF signal.
in the
voltage relay module, and keyboard! display module are
all powered from a common 21 power source which
connects to terminals 1 and 2 on the power input strip of
units, the processor module,
Terminal strips
whose coils are powered-up and powered-off by a signal
from the microprocessor. The relays switch the circuit to
which they are connected. No power is supplied to these
connections by the DSIO module.
and
are internal relays
each module. A separate source of 12.5
power is used
to power the EXV driver module through terminals 1 and
2 on the power input strip.
S E N S O R B U S C O N N E C T O R
INPUTS
:
24 VAC
CHANNEL I J3 PINS
2-
2
3 8 4
I
3-
4 -
+
ARE GROUND
COMMON
C H A N N E L
Fig. 13
Sensor Bus Wiring
Processor Module (PSIO) (Fig. 14.)
Each input channel has 3 terminals; only 2 of
the 3 terminals are used. The application of the machine
determines which terminals are used. Always refer to the
individual unit wiring for terminal numbers.
Output is 24 vdc. Again, there are 3 terminals,
only 2 of which are used; which 2 depends on the appli-
cation. Refer to unit wiring diagram.
NOTE: Both address switches must be set at zero.
COMMON
NO
CHASS IS
G R O U N D
N E T W O R K
ADDRESS ADJUSTMENT
I
(NOT
ON UNDERSIDE.
Fig,
Low-Voltage Relay Module
SENSOR BUS
ADDRESS
SW
Fig. 14
Processor Module
24
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Display Module (HSIO) (Fig.
function of the HSIO is to allow the operator
with the processor. It is used to enter
EXV Driver Module (Fig. 16.)
Input on strip am-c
When 24
are applied
2 terminals in a
is read as
and set points and to read data, perform tests and
channel it is read as an ON signal.
an OFF signal.
set
Two stepper motor driver outputs
used to
drive the electronic expansion valves, Terminals I and 7
supply voltage to the valves. Terminals 2 through 5 and
through I connect the individual coils (4 per valve) to
neutral in a repeating sequence to drive the valves in
incremental steps.
S E N S O R B U S C O N N E C T O R
RED STATUS LIGHT
G R O U N D ( C )
C O M M U N I C A T I O N
Fig. 17
Keyboard/Display Module
COIL 4
STEPPER
MOTOR 2
J4
COIL 4
STEPPER
MOTOR I
3
2
I
C O M M O N
A D D R E S S
A D J U S T M E N T
ON UNDERSIDE
Fig. 16
EXV Driver Module (DSIO)
2 5
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TROUBLESHOOTING
SYMPTOMS
CAUSE
REMEDY
SYMPTOMS
CAUSE
REMEDY
Power line open
Reset circuit breaker.
Unit operates
long or
continuously
Compressor does
not run
Control fuse
o p e n
Check control circuit
for ground or short.
Replace fuse.
Safety thermostat
tripped (DGT)
Move RUN/STANDBY
switch to STANDBY,
then back to RUN.
Tripped power
breaker
Check the controls.
Find cause of trip
and reset breaker.
Service load
lating pump not
System Noises
Compressor noisy
Check valve plates
for valve noise.
Improperly wired
controls
Check wiring and
rewire.
Low line voltage
Check line voltage
determine location of
voltage drop and
bearings)
Check for loose
compressor
down bolts.
remedy deficiency.
Compressor motor
defective
Check motor winding
for open or short.
Replace compressor,
if necessary.
Compressor
loses
Seized compressor
Compressor
cycles off on toss
of charge
Loss of charge control
erratic in action
Repair leak;
Low refrigerant charge Add refrigerant.
High-pressure control
erratic in action
Replace control.
Compressor
shuts down on
high-pressure
control
relay contacts.
Frosted
suction line
Expansion valve
Check cooler and
Open valve, or
Compressor discharge
valve partially closed
if defective.
Air in system
Purge.
Hot
line
Condenser scaled
Receiver not properly
Clean condenser.
Frosted liquid
line
as required,
providing adequate
venting.
vented
refrigerant
restricted
backs up into evap
condenser
Remove restriction
Restricted
drier
Start pump-
replace if defective.
Condenser water pump
or fans not operating
Compressor will
not unload
control
Compressor will
not load
control valve
Plugged strainer
side)
Clean or replace
strainer.
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Manufacturer reserves the right to discontinue, or change at any time, specifications or designs without notice and without incurring obligations.
Catalog No. 533-030 Printed in U.S.A. Pg l-89 Replaces: New
P C 1 1 1
Book
2
T
a
b
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