Carrier PTV Over/Under Voltage, Code 7 Auto Resetting, Performance Monitor, No Fault Code Shown

Table 32 — WSHP Troubleshooting (cont)

FAULT	HEATING	COOLING	POSSIBLE CAUSE	SOLUTION
Over/Under Voltage —	X	X	Under voltage	Check power supply and 24 vac voltage before and during operation.
Code 7 (Auto Resetting)
				Check power supply wire size.
				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 Thermistors	X		FP1 temperature is higher	Swap FP1 and FP2 thermistors.
— Code 9			than FP2 temperature.
		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.
	X	X	Compressor overload	Check and replace if necessary.
	X	X	Control board	Reset power and check operation.
Swapped Thermistor —	X	X	FP1 and FP2 swapped	Reverse position of thermistors.
Code 9
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.
Only Compressor Runs	X	X	Thermostat wiring	Check G wiring at heat pump. Jumper G and R for fan operation.
				Check Y and W wiring at heat pump. Jumper Y and R for compressor
				operation in test mode.
	X	X	Fan motor relay	Jumper G and R for fan operation. Check for line voltage across BR
				contacts.
				Check fan power enable relay operation (if present).
	X	X	Fan motor	Check for line voltage at motor. Check capacitor.
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
				operating, 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 'Click'.
Insufficient Capacity/	X	X	Dirty filter	Replace or clean.
Not Cooling or Heating
	X		Reduced or no airflow in heating	Check for dirty air filter and clean or replace.
Properly
				Check fan motor operation and airflow restrictions.
				External static too high. Check blower performance per Tables 9-13.
		X	Reduced or no airflow in cooling	Check for dirty air filter and clean or replace.
				Check fan motor operation and airflow restrictions.
				External static too high. Check blower performance per Tables 9-13.
	X	X	Leaky ductwork	Check supply and return air temperatures at the unit and at distant duct
				registers if significantly different, duct leaks are present.
	X	X	Low refrigerant charge	Check superheat and subcooling per Tables 20-23.
	X	X	Restricted metering device	Check superheat and subcooling per Tables 20-23. Replace.
		X	Defective reversing valve	Set for cooling demand and check 24 vac on RV coil and at control.
				If RV is stuck, run high pressure up by reducing water flow and while
				operating, engage and disengage RV coil voltage to push valve.
	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 condenser cleaning.
	X	X	Inlet water too hot or cold	Check load, loop sizing, loop backfill, ground moisture.

LEGEND

LED — Light-Emitting Diode

RV — Reversing Valve

TXV — Thermostatic Expansion Valve

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