Troubleshooting
No compressor Or fan
operation
X X
Power LED ON
Bad thermostat
connection / faulty
thermostat
Check thermostat and wiring. Check unit terminal
b
lock fo
r 24 VAC between "Y" and "C" and "G" and
"C."
Power LED OFF
Low or no supply
power
Ensure that the supply voltage to the unit is with in
the range shown on the unit data plate.
Faulty control
transformer
Check for 24 VAC between "R" and "C" on the unit
termina
l block. For 75 and 100 VA transformers,
check that the transformer circuit breaker has not
tripped. Check low voltage circuit for overload
conditions or short circuits before replacing the
transformer.
No Fan operation—
constant Airflow
motor
X X See Action
No fan operation
signal
Check for 24 VAC between "G" and "C." Check all
wiring connections.
Make sure that the thermostat connection plug is
securely connected.
Loose wiring
Check all wiring connections at motor and control
box. Check that power and control harnesses are
securely connected.
Interface board
problem
Make sure that the interface board is not damaged
and that
all DIP switches are in the proper
configuration (refer to the blower performance
tables).
Faulty motor
Check supply voltage to the motor. Check that all
motor wires are secure. Move the "TEST" DIP
switch to "ON" and the other switches to "OFF" on
the "ADJUST" switch block on the interface board—
the motor should run at 70% torque when "G" is
called. With power off spin the motor shaft—noise,
resistance or uneven motion can be signs of motor
failure.
Unit not shifting into
cooling and heating
X X
Reversing valve
solenoid energized
Faulty solenoid
Check that the reversing valve solenoid is receiving
24 VAC.
If it is receiving 24 VAC, check the resistance of the
solenoid—an open circuit may indicate a burned out
solenoid.
Reversing valve
solenoid NOT
energized
Miswired/faulty
thermostat
Check that the reversing valve thermostat wire is
connected to the “O” terminal of the thermostat.
Check for a contact closure between “O” and “R.”
Loose wire on “O”
terminal
Check that the wires from the thermostat to the
unit are securely connected and that the wires from
the electrical box to the reversing valve are
connected.
Unit Troubleshooting
Problem
Mode
Check Possible Cause Action
Cooling Heating
58 |
CL Series Heat Pumps — 8733838716 (2024/05)
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