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Troubleshooting
CA Model
CA Model
8733942456 (2016/04)
Subject to change without prior notice
Unit Troubleshooting
Problem
Possible Cause
Checks and Correction
ENTIRE UNIT
DOES NOT RUN
Power Supply Off
Apply power, close disconnect.
Blown Fuse
Replace fuse or reset circuit breaker. Check for correct fuses
Voltage Supply
Low
If voltage is below minimum voltage specified on unit data plate,
contact local power company.
Thermostat
Set the fan to “ON”, the fan should run. Set thermostat to “COOL” and
lowest temperature setting, the unit should run in the cooling mode
(reversing valve energized). Set unit to “HEAT” and the highest
temperature setting, the unit should run in the heating mode. If neither
the blower or compressor run in all three cases, the thermostat could
be miswired or faulty. To ensure miswired or faulty thermostat verify 24
volts is available on the condensing section low voltage terminal strip
between “R” and “C”, “Y” and “C”, and “O” and “C”. If the blower does
not operate, verify 24 volts between terminals “G” and “C” in the air
handler. Replace the thermostat if defective.
BLOWER
OPERATES BUT
COMPRESSOR
DOES NOT
Thermostat
Check setting, calibration, and wiring.
Wiring
Check for loose or broken wires at compressor, capacitor, or contactor.
Safety Controls
Check UPM board red default L.E.D. for Blink Code.
Compressor
overload open
If the compressor is cool and the overload will not reset, replace
compressor.
Compressor
motor grounded
Internal winding grounded to the compressor shell. Replace
compressor. If compressor burnout, install suction filter dryer.
Compressor
windings Open
After compressor has cooled, check continuity of the compressor
windings. If the windings are open, replace the compressor.
UNIT OFF ON
HIGH PRESSURE
CONTROL
Discharge
pressure too high
In “COOLING” mode: Lack of or inadequate water flow. Entering water
temperature is too warm. Scaled or plugged condenser. In “HEATING”
mode: Lack of or inadequate air flow. Blower inoperative, clogged filter
or restrictions in duct work.
Refrigerant
charge
The unit is overcharged with refrigerant. Reclaim refrigerant, evacuate
and recharge with factory recommended charge.
High pressure
switch
Check for defective or improperly calibrated high pressure switch.
UNIT OFF ON LOW
PRESSURE
CONTROL
Suction pressure
too low
In “COOLING” mode: Lack of or inadequate air flow. Entering air
temperature is too cold. Blower inoperative, clogged filter or
restrictions in duct work. In “HEATING” mode: Lack of or inadequate
water flow. Entering water temperature is too cold. Scaled or plugged
condenser.
Refrigerant
charge
The unit is low on refrigerant. Check for refrigerant leaks, repair,
evacuate and recharge with factory recommended charge.
Low pressure
switch
Check for defective or improperly calibrated low pressure switch.
