Heater attempts to start but shuts down with E02; fan may run briefly, then stop.

Safety first: Disconnect power to the Pahlen heater and allow it to cool. Do not run the heater with a blocked flue or damaged fan.

Step-by-step checks:

• Inspect exhaust and intake: Check the Pahlen heater flue outlet and, if applicable, combustion air intake for leaves, plastic bags, bird nests, or snow/ice. Clear any obstructions fully.
• Check condensate drain (if condensing model): Ensure the condensate trap and drain line are not clogged, kinked, or frozen. A blocked drain can cause water buildup and affect airflow.
• Inspect air pressure switch tubing: Locate the silicone tube between the flue fan housing and the air pressure switch. Make sure it is not cracked, loose, or filled with water. Replace or re-seat as needed.
• Test fan operation: With power restored, call for heat and listen for the flue fan (combustion blower) to start. If the fan does not run, check the fan wiring harness and connector at the control board. If power is present but the fan does not spin, the fan motor is likely defective.
• Check pressure switch contacts: With power off, disconnect the wires from the air pressure switch and test continuity while gently blowing into the pressure port (or using a manometer per Pahlen specs). If the switch does not close, replace it.

When to stop: If the flue system is complex (long runs, elbows, roof terminations) or you suspect improper installation, have a qualified technician evaluate the venting and combustion air system.