Electronic John Wood gas water heater will not ignite; display shows E001 and burner never lights
Safety Warning
This repair may involve working with high voltage components or water connections. Always unplug the appliance before removing any panels.
If you are not confident in your ability to perform this repair safely, we strongly recommend contacting a professional technician.
Possible Causes
How to Fix / Troubleshooting
Safety first: Turn the gas control knob to OFF, shut off the manual gas shutoff valve, and disconnect power before working on the heater. Allow the unit to cool completely.
Step-by-step checks:
- 1. Verify gas supply: Make sure the gas shutoff valve on the gas line to the heater is fully open. If other gas appliances are also not working, contact your gas supplier.
- 2. Power cycle the control: Turn the gas control/thermostat to OFF for 5 minutes, then back to ON and call for hot water. See if the E001 clears and the unit attempts ignition.
- 3. Inspect the flame sensor: Remove the burner access cover. Locate the flame sensor rod near the burner. If it is sooty or coated, gently clean it with fine emery cloth or a Scotch-Brite pad until shiny. Reinstall and test.
- 4. Check the igniter: Observe through the sight glass while the unit tries to start. If there is no spark or glow from the igniter, test the igniter for continuity with a multimeter and replace if open.
- 5. Gas control valve/thermostat: If the igniter and flame sensor test good and gas supply is confirmed, the integrated gas control valve/thermostat may be faulty. Do not attempt to disassemble the valve. Replace the entire gas control assembly.
When to call a professional: If you smell gas, cannot verify gas pressure, or are not comfortable working with gas components, stop and contact a licensed gas technician.