Goodman furnace 12 red flashes: Ignitor relay failure

Twelve red flashes indicates a failure of the ignitor relay on the control board. Goodman's own service bulletin on the equivalent fault notes that grounding is a common cause in the field.

Applies to: Goodman GMEC96 and Amana AMEC96 two-stage gas furnaces with a three-colour diagnostic LED.

What it means

The ignitor relay is the switch on the control board that energises the hot surface ignitor. A relay failure means the control cannot reliably power the ignitor, so the furnace cannot light. What makes this code worth reading alongside Goodman's service literature is the company's own field guidance on the equivalent eight-flash fault on other model families: while the nominal cause is an ignitor relay fault or a shorted ignitor, field reports linked it most often to an open or insufficient furnace ground. Grounding is therefore worth checking before a board is condemned.

Most common causes

• A failed ignitor relay on the control board.
• An open or insufficient furnace ground, which Goodman associates with the equivalent fault on other models.
• A loose blower motor ground or low voltage common ground.
• A shorted hot surface ignitor drawing more current than the relay can handle.
• Damaged ignitor wiring shorting to the cabinet.
• A control board approaching failure.

How to diagnose it

1. Note whether the ignitor glows at all during a start attempt, if the furnace has a sight glass.
2. Mention any recent electrical work, control board replacement, or blower motor replacement to the technician, since each disturbs a ground.
3. Note whether other faults have appeared alongside it, since grounding problems produce several codes at once.
4. Confirm the count is twelve and the colour is red, since this is at the long end of the code set and easy to miscount.

How to fix it

1. This is technician work on the control board and ignition circuit.
2. Ask for ground connections to the furnace chassis to be checked and tightened before the board is replaced, particularly the blower motor ground and the low voltage common ground.
3. After grounds are secured, powering the furnace off for about ten seconds and back on clears stored codes, which is Goodman's documented procedure on the related fault.
4. If the code returns with grounding confirmed good, the board is replaced.

Notes

Goodman's bulletin SF-024 documents that on some H-model furnaces the equivalent code was missing from the wiring labels and service manuals entirely, and that grounding rather than the ignitor was the most commonly reported real cause. That guidance is worth carrying into any ignitor relay diagnosis on Goodman equipment.

Related

• 9 red flashes — Grounding problem or reversed polarity
• 8 flashes — Igniter circuit fault or poor grounding

All codes for this manufacturer

Goodman and Amana furnace fault codes — every code, with what differs between models.

Sources

• Goodman Technical Services Service Bulletin SF-024 — Missing Identification of Eight (8) Flash Fault Code, 3 November 2008
• Goodman Manufacturing — Diagnostic Code Identification System (model-specific fault code lookup)