Electronic gas water heater shuts down with E03; blower may run but burner does not light.

Safety first: Turn off power and gas. Do not operate the heater with a suspected vent blockage.

• 1. Inspect venting: Follow the PVC or metal vent pipe from the heater to the termination. Check for sags, disconnections, bird nests, leaves, snow, or ice at the termination. Clear any obstructions. Ensure vent slope and length comply with the installation manual.
• 2. Check air intake: For two-pipe systems, inspect the combustion air intake pipe for blockages or screens clogged with debris. Clean as needed.
• 3. Examine pressure switch tubing: Remove the small rubber or silicone tube between the inducer housing and the pressure switch. Check for water, kinks, cracks, or blockages. Blow through the tube to clear it and replace if brittle.
• 4. Test pressure switch operation: With power off, disconnect the wires and check continuity across the pressure switch terminals while gently applying suction to the tubing port. The switch should click and show continuity when actuated. If it does not, replace the pressure switch.
• 5. Check inducer blower: Restore power and call for heat while observing the inducer. It should start smoothly and run without excessive noise. If it hums, stalls, or does not start, the inducer motor may be failing and should be replaced.
• 6. Reset and test: After corrections, reset the control (per manual) and test operation. If E03 persists, contact a qualified technician to evaluate the control board and vent design.