Heater attempts to start but shuts down with F02; fan may run briefly then stop.

Safety first: Turn off gas and electrical power before servicing. Do not operate the heater with blocked vents; risk of carbon monoxide buildup.

• Inspect air intake and exhaust: Check the Thermeau heater’s intake grill and exhaust outlet for leaves, plastic bags, nests, or snow. Clear all obstructions and ensure at least the manufacturer’s minimum clearance around the unit.
• Check blower fan operation: Restore power and call for heat while observing the combustion blower. If it does not start, listen for humming or grinding. A non-spinning or noisy fan may be seized or failed.
• Verify pressure switch tubing: With power off, inspect the silicone or rubber tubing from the blower housing to the air pressure switch. Ensure it is not cracked, kinked, or full of water/condensation. Re-seat or replace as needed.
• Test air pressure switch: Confirm the wiring connectors are tight. If you have a multimeter and training, you can check continuity across the switch when the blower is running. Replace the switch if it does not close under proper airflow.
• Reset and test: After clearing obstructions and checking components, reset the heater and call for heat. Persistent F02 usually indicates a failing blower or pressure switch that should be replaced.