Carrier 50PCH Troubleshooting, Reduced or no airflow in heat, Air temperature out of range

Table 32 — Troubleshooting

FAULT	HEATING	COOLING	POSSIBLE CAUSE	SOLUTION
Main Power Problems	X	X	Green Status LED Off	Check line voltage circuit breaker and disconnect.
				Check for line voltage between L1 and L2 on the contactor.
				Check for 24 vac between R and C on controller.
				Check primary/secondary voltage on transformer.
HP Fault — Code 2		X	Reduced or no water flow in	Check pump operation or valve operation/setting.
High Pressure			cooling
				Check water flow adjust to proper flow rate.
		X	Water temperature out of	Bring water temperature within design parameters.
			range in cooling
	X		Reduced or no airflow in heat-	Check for dirty air filter and clean or replace.
			ing	Check fan motor operation and airflow restrictions.
				Dirty air coil — construction dust etc.
				External static too high. Check Tables 8-10.
	X		Air temperature out of range in	Bring return-air temperature within design parameters.
			heating
	X	X	Overcharged with refrigerant	Check superheat/subcooling vs typical operating condition Tables 15-25.
	X	X	Bad HP switch	Check switch continuity and operation. Replace.
LP/LOC Fault — Code 3	X	X	Insufficient charge	Check for refrigerant leaks.
Low Pressure/Loss of
	X		Compressor pump down at	Check charge and start-up water flow.
Charge
			start-up
FP1 Fault — Code 4	X		Reduced or no water flow in	Check pump operation or water valve operation/setting.
Water Freeze Protection			heating
				Plugged strainer or filter. Clean or replace.
				Check water flow adjust to proper flow rate.
	X		Inadequate antifreeze level	Check antifreeze density with hydrometer.
	X		Improper freeze protect set-	Clip JW2 jumper for antifreeze (10 F) use.
			ting (30 F vs 10 F)
	X		Water temperature out of	Bring water temperature within design parameters.
			range
	X	X	Bad thermistor	Check temperature and impedance correlation.
FP2 Fault — Code 5		X	Reduced or no airflow in cool-	Check for dirty air filter and clean or replace.
Air Coil Freeze			ing
				Check fan motor operation and airflow restrictions.
Protection
				External static too high. Check Tables 8-10.
		X	Air temperature out of range	Too much cold vent air. Bring entering-air temperature within design
				parameters.
		X	Improper freeze protect set-	Normal airside applications will require 30 F only.
			ting (30 F vs 10 F)
	X	X	Bad thermistor	Check temperature and impedance correlation.
Condensate Fault —	X	X	Blocked drain	Check for blockage and clean drain.
Code 6	X	X	Improper trap	Check trap dimensions and location ahead of vent.
		X	Poor drainage	Check for piping slope away from unit.
				Check slope of unit toward outlet.
				Poor venting. Check vent location.
		X	Moisture on sensor	Check for moisture shorting to air coil.
Over/Under Voltage —	X	X	Under voltage	Check power supply and 24 vac voltage before and during operation.
Code 7				Check power supply wire size.
(Auto Resetting)
				Check compressor starting.
				Check 24 vac and unit transformer tap for correct power supply voltage.
	X	X	Over voltage	Check power supply voltage and 24 vac before and during operation.
				Check 24 vac and unit transformer tap for correct power supply voltage.
Performance Monitor —	X		Heating mode FP2>125 F	Check for poor airflow or overcharged unit.
Code 8		X	Cooling mode FP1>125 F OR	Check for poor water flow or airflow.
			FP2< 40 F
FP1 and FP2	X		FP1 temperature is higher	Swap FP1 and FP2 thermistors.
Thermistors —			than FP2 temperature.
Code 9
		X	FP2 temperature is higher	Swap FP1 and FP2 thermistors.
			than FP1 temperature.
No Fault Code Shown	X	X	No compressor operation	See scroll compressor rotation section on page 28.
	X	X	Compressor overload	Check and replace if necessary.
	X	X	Control board	Reset power and check operation.
Unit Short Cycles	X	X	Dirty air filter	Check and clean air filter.
	X	X	Unit in 'Test Mode'	Reset power or wait 20 minutes for auto exit.
	X	X	Unit selection	Unit may be oversized for space. Check sizing for actual load of space.
	X	X	Compressor overload	Check and replace if necessary.
Only Fan Runs	X	X	Thermostat position	Ensure thermostat set for heating or cooling operation.
	X	X	Unit locked out	Check for lockout codes. Reset power.
	X	X	Compressor overload	Check compressor overload. Replace if necessary.
	X	X	Thermostat wiring	Check Y and W wiring at heat pump. Jumper Y and R for compressor
				operation in Test mode.
LEGEND
RV — Reversing Valve

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