HVACopediaGoodman · Furnace
9 flashes Twinning fault
What the control is telling you
Problem with twinned furnaces. Blowers do not run together and no blower runs. This code is not stored in memory.
Applies to: GMES9, GCES9, AMES9, ACES9, VMES9, VCES9 (single stage, 92% and 96%)
Likely causes
- Twin terminals not wired together in the field
- Isolating relay missing or installed wrong
Test and repair steps
- Turn off power before repairs.
- Connect the twin terminals per the twinning diagram and check continuity of the wire.
- Confirm each furnace fan motor runs without the twin connection.
- Make sure line voltage is off before correcting wiring.
Settings for these units
- Normal status displays (7-segment) · Goodman/Amana GM9S96/AM9S96
- Normal status displays (7-segment) · Goodman/Amana GM9S80/AM9S80
- Normal status displays (7-segment) · Goodman/Amana GM9C96/AM9C96
- Minimum recommended filter size · Goodman/Amana GM9C96/AM9C96
Models that show this code
57 models in Goodman/Amana *MES9 single-stage
Other codes on the same units
- 4 flashes Primary or auxiliary limit open
- 5 flashes Flame sensed with no call for heat
- 6 flashes Rollout limit open or control fuse blown
- 7 flashes Low flame signal
- 8 flashes Igniter relay fault
- 10 flashes Open fuse - no 24 V at the control
- 11 flashes Igniter open
- 12 flashes Inducer relay fault
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Source: Goodman Service and Troubleshooting GMES9*/GCES9*/AMES9*/ACES9*/VMES9*/VCES9* (RS6612016r3) , Troubleshooting Chart p.52; LED table p.44. Summarized in our own words; check the original manual for your model.
Homeowner looking at this code? See what it means for you and when to call a technician.
For licensed technicians. Gas, electrical and refrigerant work must be done by a qualified, licensed person. Shut off power and gas before servicing, never bypass a safety control, and follow the manufacturer’s manual for the exact model; it and local codes always take priority. HVACopedia is not affiliated with any manufacturer; brand and model names only identify the equipment.