Unit displays E03 and shuts down; exhaust fan may run briefly, no ignition sequence starts.

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

• Check venting: Inspect the Alpha concentric vent kit or twin-pipe vent system from the heater to the termination. Remove any bird nests, leaves, snow, or ice blocking the intake or exhaust terminals.
• Inspect blower: Remove the front cover and locate the Alpha combustion blower assembly. Spin the blower wheel by hand; it should rotate freely without scraping. If seized or noisy, the blower motor is likely defective.
• Check wiring: Verify the blower motor connector is fully seated on the Alpha control board and that no wires are pinched or burned.
• Reset and test: Restore power and call for hot water. Listen for the blower starting. If it hums but does not spin, or does not start at all, the blower assembly or its speed sensor is faulty.

Because combustion air and venting are critical to safety, replacement of the blower assembly should be performed by a qualified technician familiar with Alpha water heaters.