Goodman furnace 2 red flashes: Pressure switch stuck closed, or an inducer error
Two red flashes means the pressure switch was closed when it should have been open, or the control has found an inducer problem. The switch must sit open at rest.
Applies to: Goodman GMEC96 and Amana AMEC96 two-stage gas furnaces with a three-colour diagnostic LED.
What it means
The pressure switch proves the inducer is actually moving air before gas is released, and it does that by sensing suction. At rest, with the inducer off, it must be open. The control verifies this before every cycle, because a switch stuck closed would prove a draft that does not exist — allowing the furnace to fire into a flue that could be blocked. Goodman pairs this with an inducer error on this control, which is a useful grouping: both mean the draft-proving chain cannot be trusted, though they sit at different points in it.
Most common causes
- Pressure switch contacts stuck or welded closed.
- The sensing hose pinched or kinked so that it traps pressure.
- Water in the sensing hose or the pressure tap holding the switch closed.
- A short in the pressure switch wiring, electrically indistinguishable from closed contacts.
- An inducer fault the control has detected separately.
- The wrong pressure switch fitted at a previous repair — these are rated per model.
- The low and high stage switches swapped during service.
How to diagnose it
- Confirm the colour is red. Two amber flashes is normal second-stage heating and two green is normal cooling.
- Note whether the inducer starts at all, since the control usually stops before that step on this fault.
- Note whether the furnace was serviced recently — a hose or switch disturbed during other work is a common trigger.
- Check the condensate drain for backing up, since water reaching the sensing hose is a frequent cause.
How to fix it
- Clearing a blocked condensate drain is reasonable homeowner work and addresses one of the causes.
- The pressure switch, its hoses, its wiring, and the inducer are technician work.
- Never jumper a pressure switch to get heat. It is the only thing between a blocked flue and a firing burner.
- Replace a failed switch with the exact part for the model, since setpoints are model-specific.
Notes
This code and the three red flash code are opposite halves of the same test — one says the switch is closed when it should be open, the other says it will not open when it should close. Reading the wrong one sends the repair in the wrong direction.