McQuay PTAC Troubleshooting
Troubleshooting can present hazards of electricity, rotating parts, sharp edges and weight.
Troubleshooting must be done by trained, experienced technicians only. Improper troubleshooting can result in equipment damage, severe personal injury or death.
Blinking diagnostic display on control pad
a. Defective room temperature sensor.
b. Defective indoor coil temperature sensor.
c. Defective outdoor coil temperature sensor.
d. High refrigerant temperature caused by dirty filters, coils or fan blades, bad fan motors, air blockage, short circuiting condensor air, outdoor louver with high pressure drop, capillary tube restriction:
e. Bad communication between control pad and main PC board. loose plug connection, defective control pad or PC board.
d. Clean coils, fans or filters. Replace fan motor. Check baffles in sleeve extension. Check free area of louver. Replace capillary tube. To restart compressor, turn unit off then back on. Wait 3 minutes for random restart.
e. Check for loose connections. Replace control pad or PC board.