Bradford White gas water heater shows E03 and shuts down; may attempt ignition several times then lock out.

Safety: Turn off power to the water heater at the breaker. Shut off gas if you will be disconnecting any combustion components.

Steps:

• Inspect venting: Check the entire intake and exhaust vent runs for obstructions (leaves, nests, snow, ice, debris). Clear any blockage. Ensure vent terminations meet Bradford White clearance requirements.
• Check condensate drain: On condensing or power vent models, verify the condensate trap and drain line are not clogged or frozen. Clean the trap and ensure proper slope for drainage.
• Test pressure switch tubing: Inspect the silicone tubing from the inducer to the pressure switch for cracks, kinks, or water. Replace or clear as needed.
• Verify pressure switch operation: With power off, disconnect the wires and check continuity across the pressure switch while the inducer is running (qualified person only). If the switch does not close when the inducer runs, replace the pressure switch.
• Check inducer motor: Listen for the inducer fan starting when there is a call for heat. If it hums, is noisy, or does not start, the inducer motor may be failing and require replacement.

Note: Venting and combustion air issues can cause carbon monoxide hazards. If you are unsure about vent sizing or routing, contact a licensed technician.