Carrier 40QNQ - Manual (Page 23)

23
TROUBLESHOOTING
See Table 12 and Table 13 for troubleshooting information.
Fault Code
Once a failure occurs with the indoor unit in operation, the green LED on the indoor unit flashes at intervals of 0.5 seconds. The fault code is
deduced from the number of times the green LED flashes, blocking unit operation. Between one flash cycle and the next one, a pause of 3
seconds elapses.
Table 12 – Green LED (Indoor Unit Fault)
CODE DESCRIPTION
3 Room Air Sensor Fault
4 Indoor Unit Coil Sensor Fault
14 Outdoor Unit Air Sensor Fault
Table 13 – Troubleshooting
PROBLEM POSSIBLE CAUSE SOLUTION
Compressor and Fan of the Outdoor
Unit Will Not Start
Unit not energized Check the main power connection.
Main switch is set to OFF Check and put it to ON position.
Main switch fuses are blown Replace fuses.
Compressor cycling protection is on Wait for 3 minutes.
Main power voltage is too low Check and set to the correct voltage.
Electrical connections are too loose or are wrong Check and tighten or correct connections.
Compressor Will Not Start, But Out-
door Fan is Operating
Electrical connections of compressor are loose or
wrong
Check and tighten or repair compressor.
Compressor Stops Due to Over---tem-
perature
Compressor burnt out; seized or protection device
on
Check for the cause and replace compressor if neces-
sary.
Wrong refrigerant charge in unit (excessive or low)
or air or other non---condensable gasses in the
circuit
Drain refrigerant, evacuate and recharge. CAUTION: Do
not vent refrigerant to the atmosphere; use refrigerant
recovery equipment.
Main voltage is too high or too low Check voltage setting and adjust if necessary.
Condenser coil obstructed Remove obstruction.
Outdoor fan off Check cause and resume operation or repair.
Wrong indoor unit thermistors Replace thermistors.
Refrigerant circuit clogged Check and remove obstructions.
Reversing valve faulty on heat pump models Replace reversing valve.
Expansion device clogged or covered with ice
Drain refrigerant, evacuate and recharge. CAUTION: Do
not vent refrigerant to the atmosphere; use refrigerant
recovery equipment.
Compressor Runs Continuously
Unit selected is too small for application require-
ments
Contact a qualified service technician for a system evalu-
ation.
Indoor temperature setting too low or too high Check temperature setting.
Outdoor unit fan faulty Replace outdoor fan.
Air or other non---condensable gasses in the cir-
cuit
Drain refrigerant, evacuate and recharge. CAUTION: Do
not vent refrigerant to the atmosphere; use refrigerant
recovery equipment.
Obstructions at air intake or dirty indoor unit filters Remove obstruction and/or clean filter.
Frequent Ice---Build---Up on Outdoor
Coil
Outdoor fan is stopped Check cause and repair.
Discharge Pressure Too High
Outdoor coil dirty or obstructed Clean or remove obstructions.
Condenser fan faulty Replace condenser fan.
Indoor temperature setting too low or too high Check temperature setting.
Air or other non---condensable gasses in the cir-
cuit
Drain refrigerant, evacuate and recharge. CAUTION: Do
not vent refrigerant to the atmosphere; use refrigerant
recovery equipment.
Discharge Pressure Too Low
Indoor temperature setting too high or too low Check temperature setting.
Outdoor coil dirty or obstructed Clean or remove obstructions.
Indoor unit air filter dirty Clean filter.
Suction Pressure Too High
Indoor temperature setting too high or too low Check temperature setting.
Reversing valve faulty or internal leak Replace reversing valve.
Suction Pressure Too Low
Indoor temperature setting too high or too low Check temperature setting.
Evaporator coil covered with ice
Air circulation on the evaporator not sufficient; check and
repair.
Expansion device or suction line clogged Check and repair.
Outdoor fan does not stop during defrost periods Check electrical parts.
Outdoor Fan Cycling Due to Over---
Temperature Protection
Electrical connection loose Check connections.
Fan motor burn out Replace.
Fan bearing seized Check and repair.
Expansion device clogged or covered with ice
Drain refrigerant, evacuate and replace.
CAUTION: Do not vent refrigerant to the atmosphere; use
refrigerant recovery equipment.