
No Cooling
1 Check for a cooling signal from the Indoor unit or thermostat, 24V AC should be present at the
Y and C terminals at the Outdoor unit'
If 24V AC is not present, check that the thermostat or Indoor unit is calling for cooling
2 If 24V AC is present, check to ensure compressor contactor is energized, if contactor is not
energized, check for voltage at the contactor coil, if voltage is present, but contactor is not
pulled in, then contactor is faulty and should be replaced
3If 24V AC is not present at the contractor, check the high and low pressure switches for
continuity, both switches are auto reset type but if no continuity can be found across either
switch it is possible that the high or low pressure situation exists or the switch is faulty
4 If the contactor has pulled in, and the compressor is not running, check the overload on the
top of the compressor for continuity, if overload is tripped replace
5 If the OLP has continuity, but the compressor is not running, check the compressor and
capacitor for operation, replace if found faulty
High Pressure Switch trip
If the High Pressure switch trips during operation the following items should be checked
1 Outdoor Fan Motor, ensure that it operates in conjunction with the compressor, if it does
not operate check the motor windings and also the fan capacitor, replace if necessary
2 Ensure the condenser coil is free from debris, clean if necessary, make sure that the
airflow to and from the unit is not impeded or discharge air from another unit is entering
this unit
3 Check system refrigerant pressure with compressor off, pressure should convert to approx
ambient temperature, this ensures that non condensibles are not present in the refrigerant
If system pressure is abnormally high reclaim refrigerant, evacuate and recharge with virgin
R410A
Low Pressure Switch Trip
If the low pressure switch trips during operation the following items should be checked
1 Refrigerant charge, low pressure trips are a symptom of a loss of refrigerant charge, check
the refrigerant piping and units for a leak
2 Check the Indoor unit to make sure it is operating and the filters are clean, a frozen Indoor unit
can be caused by low or no airflow, dirty filters, or a restriction in the line set or expansion
device
Poor Cooling Performance
Most issues with poor cooling performance are related to the Indoor unit, airflow, ductwork,
dirty filters, however also check
1 Unit refrigerant charge, check to ensure charge is correct
2 Check condenser coil for dirt and debris, clean coil if necessary
Installation and Maintenance Manual
Troubleshooting