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Table 14 - 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 V a.c. between R and C on controller.
Check primary/secondary voltage on transformer.
HP fault - code 2
X
Reduced or no water flow in cooling
Check pump operation or valve operation/setting.
High pressure
Check water flow adjust to proper flow rate.
X
Water temperature out of range in cooling
Bring water temperature within design parameters.
X
Reduced or no airflow in heating
Check for dirty air filter and clean or replace.
Check fan motor operation and airflow restrictions.
Dirty air coil - construction dust etc.
External static too high.
X
Air temperature out of range in heating
Bring return air temperature within design parameters.
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 charge
X
Compressor pump down at start-up
Check charge and start-up water flow.
FP1 fault - code 4
X
Reduced or no water flow in heating
Check pump operation or water valve operation/setting.
Water freeze protection
Plugged strainer or filter. Clean or replace.
Check water flow adjust to proper flow rate.
X
Inadequate anti-freeze level
Check anti-freeze density with hydrometer.
X
Improper freeze protect setting
Clip JW3 jumper for anti-freeze (-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 airflow in cooling
Check for dirty air filter and clean or replace.
Air coil freeze protection
Check fan motor operation and airflow restrictions.
External static too high.
X
Air temperature out of range
Too much cold vent air. Bring entering air temperature within design
parameters.
X
Improper freeze protect setting
Normal airside applications will require -1.1
°
C only.
(-1.1
°
C vs -12.2
°
C)
X
X
Bad thermistor
Check temperature and impedance correlation.
Condensate fault - code 6
X
X
Blocked drain
Check for blockage and clean drain.
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 - code 7
X
X
Under voltage
Check power supply and 24 V a.c. voltage before and during operation.
(Auto resetting)
Check power supply wire size.
Check compressor starting.
Check 24 V a.c. and unit transformer tap for correct power supply voltage.
X
X
Over voltage
Check power supply voltage and 24 V a.c. before and during operation.
Check 24 V a.c. and unit transformer tap for correct power supply voltage.
Performance Monitor -
X
Heating mode FP2> 51.7
°
C
Check for poor airflow or overcharged unit.
code 8
X
Cooling mode FP1> 51.7
°
C
Check for poor water flow or airflow.
or 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.
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
FP - Freeze protection
HP - High pressure
LP - Low pressure
RV - Reversing valve
