Amana / Goodman Furnace 3 Flash Error Code — What It Means
Both Amana and Goodman furnaces (Amana is a Goodman brand and uses the same control board platform) flash 3 blinks on the LED status indicator when the draft pressure switch circuit has faulted. The 3-flash code means the inducer pressure switch did not confirm adequate draft pressure before or during the heat cycle. Amana and Goodman users searching for either brand’s 3-flash code will find the same root cause and the same repair process — the control boards, pressure switches, and diagnostic logic are identical across both brands.
Common Causes
- Blocked or kinked pressure switch hose — The rubber hose connecting the inducer housing port to the pressure switch is the most common physical cause; it collapses, clogs with condensate, or cracks over time.
- Failed pressure switch — The switch diaphragm fails and won’t close even with adequate draft. Switches fail more quickly on high-efficiency models where the hose carries warm condensate-laden air.
- Failed inducer motor or capacitor — An underperforming inducer motor can’t generate enough negative pressure to close the pressure switch.
- Blocked intake or flue vent — A blocked PVC intake or exhaust pipe prevents proper airflow through the heat exchanger, starving the inducer of the pressure differential needed to close the switch.
Step-by-Step Fix {#fix}
- Inspect and clear the pressure switch hose — Power off the furnace. Locate the rubber hose(s) running from the inducer to the pressure switch. Look for kinks, cracks, or condensate pooling. Blow through it to verify it’s clear.
- Test the pressure switch — Disconnect the hose from the switch port and apply suction (mouth or hand pump). A good switch clicks closed at approximately -0.5” to -1.0” WC. No click means the switch has failed.
- Verify inducer operation — Restore power and watch/listen to the inducer during a heat call. Full-speed startup within a few seconds is normal. Slow or no rotation points to a seized motor or failed capacitor.
- Check the venting system — Go outside and inspect the PVC intake and exhaust terminations for blockage — bird nests, insect screens clogged with debris, or ice are common in winter.
- Reset and test — After repairs, cycle the thermostat to call for heat. If 3 flashes clear and the furnace lights, run through two full heat cycles before calling the repair complete.
Parts Often Needed
| Part | Notes |
|---|---|
| Pressure switch | Amazon | Goodman/Amana switches are model-specific; verify part number by model tag |
| Inducer capacitor | Amazon | Test before replacing the motor; often cheaper cause of slow inducer |
| Pressure switch hose | Amazon | Available by the foot at HVAC supply houses |
| Inducer motor assembly | Amazon | Replace when motor shaft is seized or winding tests open |
When to Call a Pro
If all mechanical components check out and 3 flashes persist, the heat exchanger may have a crack that disrupts the pressure dynamics in the flue system. Heat exchanger inspection requires a licensed HVAC technician — do not continue operating the furnace if a cracked heat exchanger is suspected.