How to Fix / Troubleshooting

Safety: Disconnect power before working near the fan or removing the combustion cover.

Step 1 – Listen to the fan: Call for heat and listen. If the fan hums but does not spin, or makes grinding noises, it may be seized or obstructed.
Step 2 – Inspect the fan housing: With power off, remove the fan access cover on the Triangle Tube boiler. Check for debris, broken plastic, or foreign objects in the fan wheel. Spin the wheel by hand; it should turn freely without scraping.
Step 3 – Check wiring: Verify that the multi-pin connector from the fan to the control board is fully seated and not corroded. Inspect wires for damage.
Step 4 – Reset and test: Reassemble, restore power, and reset the boiler. If E05 returns and the fan does not reach speed, the fan assembly or control board may be defective.
Professional repair: Replacement of the combustion fan and verification of combustion settings should be done by a licensed technician.

Boiler shows E05; the fan runs but the burner does not light.

Possible Causes