F11
Saunier Duval Gas valve control / modulation fault

F11 displayed, fan runs but ignition sequence does not proceed correctly

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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.

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Possible Causes

Faulty gas valve coil, Loose gas valve connector, Broken wiring between PCB and gas valve, PCB gas control output failure

How to Fix / Troubleshooting

Safety first: Turn off gas and power. Gas valve work must be done by a qualified gas technician.

Steps:

  • Visual check: Inspect the gas valve body for signs of overheating, corrosion, or water ingress.
  • Check connector: Ensure the multi-pin plug on the gas valve is fully seated and free of corrosion.
  • Wiring harness: Follow the harness back to the PCB, checking for damage or pinched cables.
  • Professional testing: A technician should measure coil resistance and verify that the PCB is sending the correct voltage during ignition. Replace the gas valve if out of specification.

Warning: Do not attempt to open or adjust the gas valve yourself. Incorrect handling can cause gas leaks and serious hazards.

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Repair Difficulty

Professional Required 5/5

Required Part

Gas Valve Assembly
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