Main
Failed Ignition Sequence / Gas Valve or Ignition Issue
Boiler cycles on and off with loud clicking from the gas valve but no sustained flame
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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
Weak spark from ignition electrode, Incorrect electrode gap, Faulty gas valve, Low gas pressure
How to Fix / Troubleshooting
Safety: Gas components must only be serviced by a Gas Safe engineer. Do not attempt DIY gas work.
- Check other gas appliances: Ensure they operate normally; if not, contact your gas supplier.
- Record symptoms: Note whether the boiler attempts to light (you may hear clicking) and whether any flame appears through the sight glass.
- Engineer tasks:
- Inspect and clean the ignition electrode and check the spark strength.
- Verify gas inlet and burner pressures against Main specifications.
- Test and replace the Main gas valve if it does not open or modulate correctly.
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Repair Difficulty
Professional Required
5/5
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