Comfortmaker Heat Pump Troubleshooting

The possible problems appearing in Comfortmaker heat pump work are described below. There is the most comprehensive list of breakdowns which you may encounter with this model.

The problems for Comfortmaker CSH6 and NXH5 modifications are described. There are descriptions of the symptoms when you see your heat pump not working, possible causes and actions. The possible reason of heat pump not cooling may be various, so all the variants are shown in the table.

For example, if you discover your heat pump fan not spinning, you may do some actions mentioned in the table, but do not use them as instructions for the repair – ask the specialists for help.

Comfortmaker CSH6 Heat Pump Troubleshooting

SymptomPossible CauseAction
Display will not come on.Thermostat is not being powered.• Check that C terminal is connected to the system transformer.
• Check for 24 Vac between C and R terminals.
— If missing 24 Vac:
— check if the circuit breaker is tripped—reset the circuit breaker.
— check if the system fuse is blown—replace the fuse.
— check if the power switch on the HVAC equipment is in the Off position—set to the On position.
— check wiring between thermostat and HVAC equipment—replace any broken wires and tighten any loose connections.
— If 24 Vac is present, proceed with troubleshooting.
Thermostat microprocessor is locked up.Remove the thermostat from the wallplate for 2 minutes. After 2 minutes, replace the thermostat on the wallplate.
Temperature display is incorrect.Room temperature display has been reconfigured.Enter Installer Setup number 37 and reconfigure the display.
Thermostat is configured for °F or °C display 3 .Enter Installer Setup number 14 and reconfigure the display.
Bad thermostat location.Relocate the thermostat.
Temperature settings will not change. (Example: Cannot set the heating higher or the cooling lower.)The upper or lower temperature limits were reached.Check the temperature setpoints:
• Heating limits are 40 to 90°F (4.5 to 32°C)
• Cooling limits are 48 to 99°F (7 to 35°C).
The setpoint temperature range stops were configured.Check Installer Setup numbers 34 and 35 and reconfigure the setpoint stops.
Heating will not come on.No power to the thermostat.• Check that C terminal is connected to the system transformer.
• Check for 24 Vac between C and R and between R and Y1 terminals.
— If missing 24 Vac:
— check if the circuit breaker is tripped—reset the circuit breaker.
— check if the system fuse is blown—replace the fuse.
— check if the system switch at the equipment is in the Off position—set to On position.
— check wiring between thermostat and HVAC equipment—replace any broken wires and tighten any loose connections.
— If 24 Vac is present, proceed with troubleshooting.
Thermostat minimum off time is activated.Wait up to five minutes for the system to respond.
System selection is not set to Heat.Set system selection to Heat.
Cooling will not come on.No power to the thermostat.• Check that C terminal is connected to the system transformer.
• Check for 24 Vac between C and R and between R and Y1 terminals.
— If missing 24 Vac:
— check if the circuit breaker is tripped—reset the circuit breaker.
— check if the system fuse is blown—replace the fuse.
— check if the system switch at the equipment is in the Off position—set to the On position.
— check wiring between thermostat and HVAC equipment—replace any broken wires and tighten any loose connections.
— If 24 Vac is present, proceed with troubleshooting.
Thermostat minimum off time is activated.• Wait up to five minutes for the system to respond.
• Enter Installer Setup number 33. Reconfigure minimum off time (if required).
System selection is not set to Cool.Set system selection to Cool.
System on Indicator (flame=heat, snowflake=cool) is displayed, but no warm or cool air is coming from the registers.Heating equipment Is not operating.Verify operation of heating equipment In self-test.
System on indicator is not displayed, but heating or cooling system is operatingOption not activated.Enter Installer Setup number 36 and reconfigure to 00.
Outdoor temperature not displayedOption not activated.Enter Installer Setup number 24 and set to 01. Thermostat must have OT terminals and a C7089B1000 installed.

Comfortmaker NXH5 Heat Pump Troubleshooting

FLASH CODEFAULT DEFINITION
On, No FlashStandby
1, PauseLow Stage
2, PauseHigh Stage
Continuous FlashEmergency Mode
16System Communications Failure
25Invalid Model Plug
31High Pressure Switch Trip
32Low Pressure Switch Trip
45Control Fault
46Brown out (230V)
47No 230v with Call to Run
53Outdoor Air Temp Sensor
55Coil Temp Sensor
56Temp Sensor Range Error
71Low Stage Thermal Cutout
72High Stage Thermal Cutout
73Contactor Shorted
74Contactor Open (No 230v to Comp)
81Low Stage Thermal Lockout (4 HRS)
82High Stage Thermal Lockout (4 HRS)
83Low Pressure Lockout (4 HRS)
84High Pressure Lockout (4 HRS)