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Carrier Error Code 45: Outdoor control board failure (Heat Pump)

Updated · by Aurora Star Tech Inc.

Carrier error code 45 on a heat pump means: Outdoor control board failure. It is also called Carrier diagnostic code 45.

High severityHeat PumpCarrier 2-stage 24ANB/25HNB · Carrier single-stage communicating HP

Homeowner? What Carrier code 45 means for you

Call a technician Your heat pump is reporting: Outdoor control board failure. The heat pump has locked out or cannot run properly. One reset is fine; if the code comes back, it needs a licensed technician to find the cause.

Safe things you can check yourself

  • Check the thermostat: right mode (Heat or Cool), set a few degrees past room temperature, and fresh batteries if it uses them.
  • Check both breakers and the outdoor disconnect box beside the outdoor unit; all should be ON.
  • Look at the air filter. If it is grey and clogged, replace it; a blocked filter causes many shutdowns.
  • In winter, keep snow and ice off and away from the outdoor unit. A short defrost cycle with steam is normal.
  • Try one reset: turn the power off for 30 seconds, then back on. If the code comes back, stop resetting and call a technician.

Call (647) 657-2977Book a service call

Licensed technicians serving Vaughan, Toronto and the GTA.

What does Carrier error code 45 mean?

Amber STATUS light flashes 45: the outdoor control has detected an internal fault.

Applies to: Carrier 25HNB6/25HNB9 two-stage HP; single-stage communicating HP

Common causes of Carrier code 45

  • Failed outdoor control board
Safety: Gas, electrical and refrigerant work must be done by a licensed technician. Turn off power and gas before servicing, never bypass a safety control, and always follow the manufacturer's manual for your exact model.

Carrier models that use code 45

25HNB62425HNB63625HNB64825HNB66025HNB92425HNB93625HNB94825HNB960

Other Carrier Heat Pump codes

CodeMeaning
16Lost communication with user interface
25Invalid model plug / inverter size
31High pressure switch open
32Low pressure trip
33Lost inverter communication
46Brownout
47No 230 V at unit
48Lost inverter communication - lockout
49Compressor over current
53Outdoor air temperature sensor fault
54Suction temperature sensor fault
55Outdoor coil temperature sensor fault

All Carrier Heat Pump error codes →

Carrier code 45: homeowner questions

What does Carrier code 45 mean?

Outdoor control board failure. Amber STATUS light flashes 45: the outdoor control has detected an internal fault.

Is it safe to keep using my heat pump with code 45?

It depends on the cause. The heat pump has locked out or cannot run properly. One reset is fine; if the code comes back, it needs a licensed technician to find the cause.

Can I reset Carrier code 45 myself?

You can try one reset (power off for 30 seconds, then on). If Carrier code 45 comes back, the cause is still there and a licensed technician should check it.

Who can fix Carrier code 45 near me?

Aurora Star Tech Inc. repairs Carrier heat pumps in Vaughan, Toronto and across the GTA. Call (647) 657-2977 or book a service call online.

Homeowner help: AC Running But Not Cooling: What to Check · Heat Pump Not Heating or Blowing Cold Air

Troubleshooting guides

Source: Carrier Residential AC & HP Application Guideline and Service Manual 24-25-9SM (text export), Table 14 Status Codes / Table 18 Troubleshooting. Written in our own words as a summary; always check the original manual.

General guidance for qualified technicians. The manufacturer's installation and service manual and local codes always take priority. Aurora Star Tech is not affiliated with, endorsed by or sponsored by any equipment manufacturer; brand and model names are used only to identify equipment and belong to their owners.

Emergency HVAC Service

647-657-2977