Goodman two flashes: the pressure switch is closed when it should be open
Goodman two flashes reports a pressure switch found closed at the wrong moment. Learn why a stuck-closed switch is treated as seriously as one that never closes.
What this means
Two flashes on a Goodman integrated control reports the pressure switch circuit closed at a point in the sequence where the control expects it open. The control checks the switch before the inducer runs, and a circuit already made at that moment means the switch cannot prove anything about draft once the inducer starts.
Equipment and model context
Goodman GMVC-series two-stage variable-speed gas furnaces documented in the installation and operating instructions
- GMVC80
- GMVC95
- GMVC96
Take this from the diagnostic table printed in the Goodman GMVC-series installation and operating instructions. Goodman has used other flash counts on earlier and later control platforms, and Amana equipment built on related controls publishes its own table. Take the count from the label inside your own furnace door.
What you may notice
- The furnace does not start a heating sequence at all, and the control LED repeats two flashes with a pause between groups.
- The inducer motor never runs, which distinguishes this from the codes that appear after the draft motor has started.
- The fault is present from the first call for heat rather than developing part way through a cycle.
Likely causes
- A pressure switch contact set that has welded or stuck closed no longer opens when the inducer is off.
- Water or condensate bridging the switch or its tubing can hold the circuit made independently of any draft.
- A wiring fault that shorts across the switch terminals presents the same electrical state as a switch that will not open.
Diagnostic paths
Nothing happens at all when heat is called for
The thermostat calls, the furnace stays silent, and no inducer noise or igniter glow occurs at any point in the following minutes.
Confirm the thermostat is set to heat and calling, then read the flash count through the sight glass and leave the furnace off. Silence with a code is different from a furnace that tries and fails.
It started after a wet or freezing spell
The code appeared during or just after a period of heavy condensation, driving rain, or hard frost around the flue or the furnace.
Record the weather and any visible water around the furnace base. Moisture in the switch tubing is a distinct branch from a failed contact set.
The furnace was worked on recently
Someone carried out service, a part replacement, or an installation change shortly before the code appeared.
Say what was done and when. A tube left off, reversed, or pinched during work produces this reading without any component having failed.
Proving is a before-and-after test, which is the part most explanations skip. The control has to see the switch open with the inducer off so that seeing it closed with the inducer running actually means something.
- Inducer offThe switch must read open
- Inducer onThe switch must then close
- Both states seenDraft is genuinely proven
- Always closedThe test proves nothing at all
| Switch state | When the control notices | What it prevents |
|---|---|---|
| Will not close | After the inducer starts | Firing without proven draft |
| Will not open | Before the inducer starts | Firing on a switch that proves nothing |
| Opens mid-cycle | During the burner run | Continuing after draft is lost |
The check before the check
Most people meet the furnace pressure switch as the device that has to close before the burners light. That is only half of its job. The control also has to confirm the switch is open before the inducer starts, because a switch that is stuck closed would close on cue whether or not any draft existed. Without the open reading first, the closed reading afterwards carries no information.
That is why this fault stops the furnace before anything happens rather than part way through a cycle. It is not that the furnace tried and failed. It is that the control refused to begin a sequence it could not verify, which is a different and slightly more reassuring failure than most.
Water is the branch people miss
A high-efficiency furnace produces liquid condensate by design, and that condensate travels in tubes and traps that are only a few millimetres across. When one of them fills, the pressure signal reaching the switch stops reflecting draft and starts reflecting a column of water. On a cold snap, the same fluid freezes, and the effect can arrive and disappear with the weather.
This is why the fault sometimes tracks conditions rather than appearing once and staying. Recording when it happens, what the weather was doing, and whether any water is visible around the furnace base gives a technician a reason to look at the condensate arrangement before condemning a switch. The furnace pressure switch reference covers the proving sequence in more detail, and the frozen condensate guide covers the winter version of the same problem.
What to give the technician
Report the Goodman model and serial number, the two-flash count, that the inducer never started, the weather when the fault appeared, and any recent work on the furnace or its venting.
Safe homeowner checks
- Read the flash count through the door sight glass rather than removing the blower door, since opening it can cut control power and clear the code.
- Confirm the thermostat is set to heat, is calling, and has good batteries if it uses them.
- Look for standing water or staining around the base of the furnace and note anything you find without touching tubing or switches.
Is a reset appropriate?
Cutting power clears the stored code, and the control repeats the same pre-start check on the next call for heat. A code that returns immediately is reporting a switch state that has not changed.
When to call a technician
- Testing a pressure switch, clearing condensate tubing, and inspecting the inducer and vent path are licensed gas-furnace tasks.
- Never bridge, jumper, or bypass a pressure switch to make a furnace run. The switch is the only thing confirming that combustion products are leaving the building.
Questions people ask about this
Why does the furnace check the pressure switch before starting?
The control needs to see the switch open with the inducer off so that a closed reading with the inducer running is meaningful. Without the first reading, the second one cannot prove that draft exists.
Can I jumper the pressure switch to get heat?
No. Bypassing it removes the only confirmation that combustion products are leaving through the vent, which is the condition the switch exists to prove before gas is allowed to burn.
Is two flashes the same on every Goodman furnace?
Flash counts belong to a control platform rather than to a brand. Read the diagnostic label inside your own furnace door and match it to the installation instructions for that exact model.
Evidence recordHow this page was checked
service manual, official manufacturer support article · checked 2026-09-15
Every technical claim above was written from primary documentation held in the HVAC Bench evidence record: Goodman technical literature. Where a source limits a definition to certain models, test conditions, or product classes, that limit is repeated here rather than generalised.
- Documentation class
- service manual, official manufacturer support article
- Scope of the definition
- Goodman GMVC-series two-stage variable-speed gas furnaces documented in the installation and operating instructions
- Last checked
- 2026-09-15