Heater shows E12; may indicate low gas pressure or gas valve fault during ignition.
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
Critical Safety: Gas system diagnostics beyond visual checks must be performed by a licensed gas technician. Do not disassemble the gas valve.
Homeowner checks:
- Verify gas supply: Ensure the manual gas shutoff valve to the heater is fully open. Check if other gas appliances (stove, furnace) are operating normally.
- Look for recent changes: If a new gas appliance was added or piping was modified, the gas line to the heater may now be undersized.
- Inspect gas line for damage: Look for obvious kinks, corrosion, or physical damage to the exposed gas piping near the heater.
If E12 persists, a technician should measure inlet and manifold gas pressures, verify proper orifice sizing, and test the gas valve. Replacement of the gas valve should only be done by a qualified professional.