GSW power vent water heater shows E004 and the blower does not start

Safety: Turn off power at the breaker and close the gas shutoff valve before servicing.

• Check power to unit: Verify the heater has 120 V at the junction box or power cord. Reset any tripped breaker or GFCI.
• Inspect blower connections: Remove the access cover to the control compartment. Confirm the blower plug is fully seated on the control board and that no wires are burnt or broken.
• Spin blower wheel: With power off, remove the blower housing cover if accessible and spin the wheel by hand. If it is stiff, scraping, or seized, the blower assembly must be replaced.
• Test blower motor (advanced): A technician can test for proper voltage at the blower terminals when a call for heat is present. If voltage is present but the blower does not run, replace the blower assembly with a GSW-compatible unit.
• Control board check: If the blower and wiring test good but E004 persists, the control board may not be sending power and should be diagnosed and replaced by a professional.