Code 11 displayed, boiler locks out, may be related to gas valve control
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 warning: Gas valve diagnostics and replacement must only be performed by a licensed gas technician. Do not attempt DIY repairs on gas components.
Technician steps:
- Visual inspection: Check the Intergas gas valve wiring plug for secure fit and signs of overheating or corrosion.
- Coil resistance: With power off, measure the resistance of the gas valve coils and compare to Intergas specifications.
- Check modulation signal: During operation, verify that the PCB sends the correct modulation voltage/current to the gas valve.
- Verify gas settings: Confirm that the gas valve has been set up and adjusted according to the Intergas commissioning procedure, including CO₂ measurements.
If the gas valve fails tests, replace it with an OEM Intergas-specified valve and recommission the appliance. If the valve is good but control is erratic, the PCB may need replacement.