Boiler locks out with E09 after several failed ignition attempts
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: Gas work is hazardous. If you smell gas, shut off the main gas supply, avoid using electrical switches, and contact your gas supplier or emergency services. Most gas valve diagnostics and all replacements should be done by a licensed technician.
- Check manual gas valves: Ensure the gas shutoff valve near the Dettson boiler is fully open (handle parallel to the pipe).
- Verify other gas appliances: Confirm that other gas appliances (stove, water heater) operate normally. If none work, contact the gas utility.
- Inspect wiring: With power OFF, check the gas valve connector and wiring harness for secure fit and no visible damage.
- Professional testing: A technician should measure gas pressure at the inlet and outlet of the Dettson gas valve and verify coil resistance. If the valve does not open when commanded, it must be replaced.
- Reset after service: Once gas supply and valve operation are confirmed, reset the boiler and monitor for normal ignition.
Repair Difficulty
Required Part
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