Carrier 50PSW036-360 specifications Troubleshooting, Fault Heating Cooling Possible Cause Solution

Table 13 — 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 range	Bring water temperature within design parameters.
				in cooling
		X	X	Overcharged with refrigerant	Check superheat/subcooling vs. typical operating condition.
		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.
Source Water Freeze				heating
					Plugged strainer or filter. Clean or replace.
Protection
					Check water flow adjust to proper flow rate.
		X		Inadequate antifreeze level	Check antifreeze density with hydrometer.
		X		Improper freeze protect setting	Clip JW3 jumper for antifreeze (–12.2 C) use.
				(–1.1 C vs –12.2 C)
		X		Water temperature out of range	Bring water temperature within design parameters.
		X	X	Bad thermistor	Check temperature and impedance correlation.
FP2 Fault — Code 5			X	Reduced or no water flow in	Check pump operation or water valve operation/setting.
Load Coil Freeze				heating
					Plugged strainer or filter. Clean or replace.
Protection
					Check water flow adjust to proper flow rate.
			X	Improper freeze protect setting	Clip JW3 jumper for antifreeze (–12.2 C) use.
				(–1.1 C vs –12.2 C)
			X	Water temperature out of range	Bring water temperature within design parameters.
		X	X	Bad thermistor	Check temperature and impedance correlation.
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>51.7 C	Check for overcharged unit.
Code 8
			X	Cooling mode FP1>51.7 C OR	Check for poor water flow or airflow.
				FP2< 4.4 C
No Fault Code Shown		X	X	No compressor operation	See scroll compressor rotation section.
		X	X	Compressor overload	Check and replace if necessary.
		X	X	Control board	Reset power and check operation.
Unit Short Cycles		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.
Unit Does Not Operate in			X	Reversing valve	Set for cooling demand and check 24-vac on RV coil and at control.
Cooling
					If RV is stuck, run high pressure up by reducing water flow and while operat-
					ing engage and disengage RV coil voltage to push valve.
			X	Thermostat setup	Check for ‘O’ RV setup not ‘B’.
			X	Thermostat wiring	Check O wiring at heat pump. Jumper O and R for RV coil.
Insufficient Capacity/		X	X	Low refrigerant charge	Check superheat and subcooling.
Not Cooling or Heating
		X	X	Restricted metering device	Check superheat and subcooling. Replace.
Properly
			X	Defective reversing valve	Perform RV touch test.
		X	X	Thermostat improperly located	Check location and for air drafts behind thermostat.
		X	X	Unit undersized	Recheck loads and sizing. Check sensible cooling load and heat pump
					capacity.
		X	X	Scaling in water heat exchanger	Perform scaling check and clean if necessary.
		X	X	Inlet water too hot or cold	Check load, loop sizing, loop backfill, ground moisture.
High Head Pressure			X	Scaling in water heat exchanger	Perform scaling check and clean if necessary.
		X	X	Unit overcharged	Check superheat and subcooling. Reweigh in charge.
		X	X	Non-condensables in system	Vacuum system and reweigh in charge.
		X	X	Restricted metering device	Check superheat and subcooling. Replace.
Low Suction Pressure		X		Reduced water flow in heating	Check pump operation or water valve operation/setting.
					Plugged strainer or filter. Clean or replace.
					Check water flow adjust to proper flow rate.
		X		Water temperature out of range	Bring water temperature within design parameters.
	LEGEND
FP	— Freeze Protection
HP	— High Pressure
LED — Light-Emitting Diode
LOC — Loss of Charge
LP	— Low Pressure
RV	— Reversing Valve

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