Yellow 9 flashes Low 24 V control voltage (older ComfortNet board)

What the control is telling you

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

Likely causes

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

Test and repair steps

1. Warning: Kill power to the outdoor unit before touching wiring, the compressor terminals or the control.
2. Check the fuse.
3. Measure R to C with loads on; replace the transformer if it sags.
4. Check line voltage to the transformer.

Models that show this code

23 models in Goodman/Amana ComfortNet ASXC/GSXC/DSXC

Other codes on the same units

• Yellow 2 flashes High side fault / high pressure trip / high pressure lockout (older ComfortNet board)
• Yellow 3 flashes Short cycling (older ComfortNet board)
• Yellow 4 flashes Locked rotor (older ComfortNet board)
• Yellow 5 flashes Open circuit (older ComfortNet board)
• Yellow 6 flashes Open start circuit / lockout (older ComfortNet board)
• Yellow 7 flashes Open run circuit / lockout (older ComfortNet board)
• Yellow 8 flashes Low or high line voltage (older ComfortNet board)
• Yellow ON + Red ON Compressor protector open (older ComfortNet board)