Boiler will not start at all, no display or lights
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: Only check user-accessible fuses and switches. Do not remove boiler covers to access internal wiring unless competent and power is isolated.
- Check fused spur: Ensure the boiler's fused spur is switched on and the fuse (typically 3A) is intact. Replace with the correct rating if blown.
- Check consumer unit: Look for any tripped MCB or RCD and reset if appropriate. If it trips again, call an electrician.
- Check external controls: Ensure the programmer is powered and calling for heat.
- Engineer tasks:
- Test incoming voltage at the boiler terminals.
- Inspect and repair internal wiring and fuses.
- Replace a faulty main PCB or power switch if required.
If fuses blow repeatedly, do not keep replacing them; a fault must be located and repaired.
Repair Difficulty
Required Part
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