Manual 2100-737A
Page
19 of 25
SERVICE
TABLE 1 – Troubleshooting
Sympton
Description, Check & Possible Cause
What & How to Check/Repair
Compressor will not
start (heating or
cooling)
1. Check for LED illumination.
Is there an LED illuminated on the board
(flashing)?
Yes = go to Step #2; No = go to Step #3
2. Check for error codes.
Is the LED flashing a code?
Yes = go to Step #4; No = go to Step #8
3. Check for power at board.
Is there 24 volts AC between R and C?
Yes = go to Step #13; No = go to Step #9
4. Check codes.
What code is blinking?
Code "1", got to Step #6; Code "2", go to Step #7; Fast Blink, go to Step #5
5. Compressor delay active.
Wait for 5 minute delay or jump board's
"speed up pins".
Check for proper operation; if still needed, go back to Step #1
6. Low pressure fault.
Check wiring circuit and unit pressures.
7. High pressure fault.
Check wiring circuit and unit pressures.
8. Check for Compressor input signal.
Is there 24 volts AC between Y and C?
Yes = go to Step #10; No = go to Step #11
9. No power to board.
The unit either does not have unit voltage, the transformer is bad or the unit wiring
is incorrect.
10. Check for Compressor output signal.
Is there 24 volts AC between CC and C?
Yes = go to Step #12; No = go to Step #13
11. No "Y" compressor input signal.
Check thermostat wiring, incorrect phase of unit (see section on Phase Monitor)
and finally unit wiring.
12. No "CC" compressor output signal.
Check compressor contactor for proper operation and finally check compressor.
13. Faulty board.
Replace defrost board.
Fan outdoor motor
does not run (cool-
ing or heating except
during defrost)
Heat pump control defective
Check across fan relay on heat pump control. (Com-NC)
Replace heat pump control.
Motor defective
Check for open or shorted motor winding. Replace motor.
Motor capacitor defective
Check capacitor rating. Check for open or shorted capacitor. Replace capacitor.
Reversing valve
does not energize
(heating only)
Heat pump control defective
Check for 24 V between RV-C and B-C.
1. Check circuit control wiring.
2. Replace heat pump control.
Reversing valve solenoid coil defective
Check for open or shorted coil.
Replace solenoid coil.
Unit will not go into
defrost (heating
only)
Temperature sensor or heat pump control
defective
Disconnect temperature sensor from board and jumper across "SPEEDUP" terminals
and "SEN JMP" terminals. This should cause the unit to go through a defrost cycle
within one minute.
1. If unit goes through defrost cycle, replace temperature sensor.
2. If unit does not go through defrost cycle, replace heat pump control.
Unit will not come
out of defrost
(heating only)
Temperature sensor or heat pump control
defective
Jumper across "SPEEDUP" terminal. This should cause the unit to come out of
defrost within one minute.
1. If unit goes through defrost cycle, replace temperature sensor.
2. If unit does not go through defrost cycle, replace heat pump control.
SOLID STATE HEAT PUMP CONTROL
TROUBLESHOOTING PROCEDURE
1.
NOTE:
A thorough understanding of the defrost
cycle sequence is essential. Review that section
(page 17) prior to troubleshooting the control.
Turn on AC power supply to unit.
2. Turn thermostat blower switch to “fan on”—
the indoor blower should start. (If it doesn’t,
troubleshoot indoor unit and correct problem.)
3. Turn thermostat blower to “auto” position. Indoor
blower should stop.
NOTE:
Many models have a
1-minute blower time delay on “off” command;
wait for this to time out.
4. Set system switch to “heat” or “cool”. Adjust
thermostat to call for heat or cool. The indoor
blower, compressor and outdoor fan should start.
NOTE:
If there was no power to 24 volt transformer,
the compressor and outdoor fan motor will not
start for 5 minutes. This is because of the
compressor short cycle protection.
LED BLINK CODES
BLINK
FUNCTION
Slow
Normal function (1.0 sec on/1.0 sec off)
Fast
Compressor Delay timer active
(0.1 sec on/0.1 sec off)
1
Low pressure switch failure
2
High pressure switch failure/“Soft” Lockout
3
Defrost mode active
4
High pressure switch failure/“Hard” Lockout
