Goodman furnace 3 double red flashes: Second stage pressure switch stuck open, or an inducer error
Three double red flashes means the second stage pressure switch did not close when the furnace called for high fire. The furnace usually still runs on low fire, so the symptom is reduced output rather than no heat.
Applies to: Goodman GMEC96 and Amana AMEC96 two-stage gas furnaces with a three-colour diagnostic LED. This is a distinct pattern from three single red flashes, which signals the first stage.
What it means
A two-stage furnace carries two pressure switches, one per firing rate, because high fire moves considerably more combustion air and needs its own proof of draft. Goodman distinguishes the two failures by pattern rather than by count: three single flashes for first stage, three double flashes for second. The practical consequence of the second-stage version is distinctive — the furnace is not dead. It runs on low fire, which in mild weather may be perfectly adequate, so the fault often goes unnoticed until the weather turns and the house cannot keep up.
Most common causes
- The second stage pressure switch has failed and no longer closes.
- The sensing hose to the second stage switch is disconnected, kinked, or blocked.
- The inducer is not reaching high stage speed, so the switch never sees its rated pressure.
- A partly restricted vent or intake — adequate for low fire, insufficient for high fire, which is exactly why the fault appears only at second stage.
- A partly blocked condensate drain, which restricts more at the higher firing rate.
- The two pressure switches swapped during a previous repair.
- A wiring fault in the second stage switch circuit.
How to diagnose it
- Confirm the pattern is double flashes rather than single. That distinction is what separates this from the first-stage code.
- Note whether the house heats slowly rather than not at all, which fits this fault and rules out several others.
- Check the outside vent termination — a partial restriction is exactly what produces a high-stage-only failure.
- Check the condensate drain for slow drainage rather than complete blockage.
- Note whether the fault followed a service visit, since swapped switches are a real cause.
How to fix it
- Clear the vent termination and condensate drain if either is restricted. Both are within homeowner reach.
- The pressure switches, hoses, and inducer are technician work.
- Have the technician confirm the switches are fitted the right way round if the furnace was recently serviced.
- Do not simply live with low fire and ignore the code. The partial restriction usually worsens and eventually affects low fire too.
Notes
Using a double-flash pattern to distinguish stages is unusual and easy to miss if you are counting quickly. Watching two or three full cycles of the pattern before deciding is worth the extra half minute.
Related
- 3 red flashes — First stage pressure switch stuck open, or an inducer error
- 6 red flashes — Pressure switch cycle lockout
All codes for this manufacturer
Goodman and Amana furnace fault codes — every code, with what differs between models.
Models this code appears on
From the manufacturer's per-model database. If your model is not listed, this code may not exist on your board, or it may mean something different — check the model page.
The same fault on other control families
Second-stage pressure switch faults are rarer as published codes because only two-stage furnaces can have them. Within Goodman's own range, the single-LED GMV8 and GMV9 boards raise the equivalent as nine flashes — high stage pressure switch stuck open, and York's three double red flashes mirrors this board directly, as most of this table does. The broader stuck-open mechanism, shared with the first-stage version, is documented across twelve control families on the pressure switch code hub.
What the fix costs
Pressure switch work runs $150–400 per the repair cost guide, and the second-stage switch sits in the same band as the first-stage one. What makes this code cheaper in practice is scheduling: because the furnace usually keeps heating on low fire, this is reduced output rather than no heat — which means it can wait for a normal appointment instead of an after-hours call carrying the $100–200 emergency premium. Booking it promptly still matters; a two-stage furnace limited to low fire will be found out by the first serious cold front, at which point the same repair becomes an emergency one.
DIY or call a pro?
The homeowner's role is recognising the symptom for what it is: the house holds temperature on mild days and slips behind on cold ones, while the furnace runs long low-fire cycles. Confirming the pattern — and checking the outdoor terminations for obstructions, as with any pressure switch code — is safely yours. The second-stage chain itself is not: proving whether the switch, the inducer's high-speed performance, or the tubing is at fault takes a manometer on a running furnace. Do not treat the working low stage as a reason to skip the repair; it is the reason you get to schedule it on your terms.
What this looks like
From the outside, this usually shows up as the inducer spins up but the burners never fire — that walkthrough covers what to check in order, and when it stops being a homeowner job.