GVZC20 Service Manual

TROUBLESHOOTING
98
(*1) This message displayed when using the CTKO4 thermostat.
(*2) This specication of *VZC20**1 or earlier model are di󰀨erent from this specication. For details, see the service manual that matches the major revisoin of model name.
Fault Code
Control Board
LED Display
Transmitted Climate
Talk Message
Thermostat Fault Probable Causes Corrective Actions
22 E22 HI DISCH TEMP
This error indicates the equipment
is experiencing frequent high
discharge temperature faults.
Discharge thermistor is not put on
correct position.
● Discharge thermistor inoperable or
improperly connected
● Discharge thermistor is put on
incorrect position or off
● Low refrigerant charge
● Overcharge
● Faulty compressor
● Check discharge thermistor resistance and
connections; Repair/replace as needed
● Check discharge thermistor position
● Check refrigerant charge level; Adjust if
needed
● Check the compressor; Repair/replace if
needed
23 E23 DISCH TEMP FAIL
The control has detected that the
Discharge Temperature Sensor is
out of range.
● Discharge thermistor inoperable or
improperly connected
● Check discharge thermistor resistance and
connections; Repair/replace as needed
24 E24 HPS OPEN
The high pressure switch is open.
● High pressure switch (HPS)
inoperable
● Check resistance on HPS to verify operation;
Replace if needed
25
E25
AIR SENSOR FLT
The outdoor air temperature
sensor is open or shorted.
● Faulty outdoor thermistor sensor or
disconnect
● Inspect and test sensor; Replace sensor if
needed
26
E26
PRESSURE SENSOR
The control determines that the
pressure sensor is not reacting
properly.
● Low pressure sensor inoperable or
not properly connected
● Check the connection to low pressure
sensor; Repair/replace if needed
27 E27 COIL TEMP FAIL1
The control detects that the
Outdoor Defrost Sensor is out of
range.
● Outdoor defrost thermistor inoperable
or not properly connected
● Check the connection to OD defrost
thermistor; Repair as needed
28 E28 COIL TEMP FAIL2
The control has detected that the
Outdoor Coil Temperature Sensor
is out of range.
● Outdoor coil thermistor inoperable or
not properly connected
● Check the connection to OD coil thermistor;
Repair/replace if needed
29 E29 LIQ TEMP FAIL
The control has detected that the
Liquid Temperature Sensor is out
of range.
● Liquid thermistor inoperable or not
properly connected
● Check the connection to liquid thermistor;
Repair/replace if needed
30 E30 OD CTRL FAIL3
Indicates the control board may
need to be replaced.
● Wiring to control board disconnected
● Faulty control board
● Noise
● Check wiring to control board; Repair as
needed
● Replace control board if necessary
31 E31 HI LEAK CURRENT
The control has detected high
leakage current (high voltege).
● Improper ground
● Faulty compressor
●Check ground screws/lugs and wiring;
Repair/replace if needed
● Check the compressor; Repair/replace if
needed
32*
2
E32 HI TEMP CTRL1
This error indicates the equipment
is experiencing high temperature
faults on the outdoor control board.
● Ambient air conditions too high
● Cooling bracket screw(s) missing or
not properly fastened (2-4 ton only)
● No or poor thermal grease coating
between cooling plumbing and cooling
bracket on control board (2-4 ton only)
● Outdoor fan low speed (5 ton only)
● No flow or limited flow through control
board cooling circuit (potential
restriction in line or low refrigerant) (2-4
ton only)
● Stop valve not completely open (2-4
ton only)
● Cycle power; re-try during usable ambient
temperature range
● Verify cooling bracket screws in place and
secure; Secure fasteners as needed (2-4 ton
only)
● Check thermal grease inside cooling bracket
on control board; Apply additional grease as
needed
● Check outdoor fan motor & wiring;
Repair/replace if needed (5 ton only)
● Check for restriction in line
● Check refrigerant charge level; Adjust if
needed (2-4 ton only)
● Check the opening of stop valve, should be
full open;
Repair/replace if needed (2-4 ton only)
33*
2
- HI TEMP CTRL2
This error indicates the equipment
is experiencing high temperature
faults on the outdoor control board.
Control has determined continued
operation is acceptable. This
indicates they may be a problem
with the equipment.
● Ambient air conditions too high
● Cooling bracket screw(s) missing or
not properly fastened (2-4 ton only)
● No or poor thermal grease coating
between cooling plumbing and cooling
bracket on control board (2-4 ton only)
● Outdoor fan low speed (5 ton only)
● No flow or limited flow through control
board cooling circuit (potential
restriction in line or low refrigerant) (2-4
ton only)
● Stop valve not completely open (2-4
ton only)
● Cycle power; re-try during usable ambient
temperature range
● Verify cooling bracket screws are in place
and secure; Secure fasteners as needed (2-4
ton only)
● Check thermal grease inside cooling bracket
on control board; Apply additional grease as
needed
● Check outdoor fan motor & wiring;
Repair/replace if needed (5 ton only)
● Check for restriction in line
● Check refrigerant charge level; Adjust if
needed (2-4 ton only)
● Check the opening of stop valve - it should
be fully
open; Repair/replace if needed (2-4 ton only)
34 E34 CURRENT SPIKE
Board detected a high current
condition. This indicates the
potential for a short circuit.
● Current spike in supply
● Stop valve not completely open
● The compressor wire is lost phase
● Faulty control board
● Faulty compressor
● Check power supply for in-rush current
during start-up or steady state operation
● Check the opening of stop valve, should be
full open; Repair/replace if needed
● Check the wire between control board and
compressor
● Replace control board if necessary
● Check the compressor; Repair/replace if
needed
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