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Goodman Error Code Yellow 9 flashes: Low 24 V control voltage (older ComfortNet board) (Heat Pump)

Updated · by Aurora Star Tech Inc.

Goodman error code Yellow 9 flashes on a heat pump means: Low 24 V control voltage (older ComfortNet board). It is also called Goodman diagnostic code Yellow 9 flashes.

Medium severityHeat PumpGoodman/Amana ComfortNet ASZC/GSZC/DSZC

Homeowner? What Goodman code Yellow 9 flashes means for you

Check, then call Your heat pump is reporting: Low 24 V control voltage (older ComfortNet board). This is often caused by something simple. Try the safe checks below; if the code returns, book a service call before it turns into a no-heat or no-hot-water emergency.

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 Goodman error code Yellow 9 flashes mean?

Yellow LED 9 flashes: control voltage below 18 VAC; clears when it rises above 21 VAC. Same as code 09 on newer boards.

Applies to: Earlier ComfortNet condensers/heat pumps with the PCBHR101-103 or PBBGR101-102 outdoor control (green, yellow and red status LEDs) - ASXC/DSXC/ASZC/DSZC revisions before the PCBHR104 change

Common causes of Goodman code Yellow 9 flashes

  • Overloaded transformer
  • Low line voltage
  • Blown fuse / wiring fault
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.

Goodman models that use code Yellow 9 flashes

Show all 24 models

ASZC160241ASZC160361ASZC160421ASZC160481ASZC160601ASZC180241ASZC180361ASZC180481ASZC180601DSZC160241DSZC160361DSZC160481DSZC160601DSZC180361DSZC180481DSZC180601GSZC160241GSZC160361GSZC160481GSZC160601GSZC180241GSZC180361GSZC180481GSZC180601

Other Goodman Heat Pump codes

CodeMeaning
Yellow 3 flashesShort cycling (older ComfortNet board)
Yellow 4 flashesLocked rotor (older ComfortNet board)
Yellow 5 flashesOpen circuit (older ComfortNet board)
Yellow 6 flashesOpen start circuit / lockout (older ComfortNet board)
Yellow 7 flashesOpen run circuit / lockout (older ComfortNet board)
Yellow 8 flashesLow or high line voltage (older ComfortNet board)
Yellow ON + Red ONCompressor protector open (older ComfortNet board)

All Goodman Heat Pump error codes →

Goodman code Yellow 9 flashes: homeowner questions

What does Goodman code Yellow 9 flashes mean?

Low 24 V control voltage (older ComfortNet board). Yellow LED 9 flashes: control voltage below 18 VAC; clears when it rises above 21 VAC. Same as code 09 on newer boards.

Is it safe to keep using my heat pump with code Yellow 9 flashes?

It depends on the cause. This is often caused by something simple. Try the safe checks below; if the code returns, book a service call before it turns into a no-heat or no-hot-water emergency.

Can I reset Goodman code Yellow 9 flashes myself?

You can try one reset (power off for 30 seconds, then on). If Goodman code Yellow 9 flashes comes back, the cause is still there and a licensed technician should check it.

Who can fix Goodman code Yellow 9 flashes near me?

Aurora Star Tech Inc. repairs Goodman 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: Goodman ComfortNet ASXC/GSXC/DSXC, ASZC/GSZC/DSZC, AVPTC/MBVC service manual, diagnostic/status LED table (PCBHR101-103, PBBGR101-102) p.65-69. 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