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Quick answer
A boiler with no lights and a blank display is not getting power, or its internal power supply has failed. Check the fused spur next to the boiler is switched on, that the RCD or circuit breaker in your consumer unit has not tripped, and whether other electrics in the house are working. If power reaches the spur but the boiler stays dead, the fuse in the spur or inside the boiler may have blown, or the PCB may have failed. A Gas Safe engineer should diagnose anything beyond the spur and consumer unit.
Key takeaways
- Start with the simple checks: fused spur switch, consumer unit and whether the rest of the house has power.
- A blown fuse in the spur usually has a cause; replacing it without finding out why may only work briefly.
- A dead display with power at the spur points to an internal fuse or PCB fault.
- Power cuts and surges can damage boiler electronics.
- Never open the boiler casing to check internal fuses yourself.
Step-by-step checks
- Is there power in the house? If other lights and sockets are off, you have a wider power cut. Check your network operator’s power cut map or call 105.
- Check the fused spur. It is usually a switch with a small fuse carrier, near the boiler. Make sure it is on.
- Check the consumer unit. Look for a tripped RCD or MCB. If it trips again when reset, see boiler tripping the electrics.
- Check the spur’s fuse. If you are comfortable doing so, switch off and replace the spur fuse with one of the same rating. If it blows again, stop and call an engineer.
- Check external controls. Some boilers show a blank display if an external programmer or wireless receiver has failed in a particular way. Check the receiver lights.
When the fault is inside the boiler
If there is power at the spur and the boiler is still dead, the likely causes are an internal fuse on the PCB, a failed transformer or power supply section on the board, or a wiring fault inside the appliance. Internal fuses often blow because another component has failed, such as a pump or fan, so simply replacing the fuse is not a fix. See boiler PCB fault.
After a power cut
Some boilers need a manual reset after power returns, and some lose their clock settings. If the display is blank after a power cut, check the spur and consumer unit first. Surges when power returns can occasionally damage electronics.
Staying warm in the meantime
If the boiler is down in cold weather, see how to stay warm until the engineer arrives and protect your pipes from freezing.
Book with Gasmaster
Boiler completely dead? Gasmaster Plumbing & Heating, Gas Safe registered (220932), carries out boiler repairs and emergency boiler repairs across Stoke-on-Trent, Newcastle-under-Lyme and Biddulph.
Frequently asked questions
Why has my boiler suddenly got no power?
The most common reasons are a tripped RCD, the spur being switched off, or a blown fuse.
Can I change the fuse inside my boiler?
No. Internal fuses are inside the gas appliance and should only be accessed by a Gas Safe engineer.
Does a blank display mean I need a new boiler?
Not usually. Many causes are fuses, controls or a repairable board fault.
Sources
- Electrical Safety First (electricalsafetyfirst.org.uk)
- Energy Networks Association, power cut helpline 105 (energynetworks.org)
- Gas Safe Register (gassaferegister.co.uk)
Related services
Abdul runs Gasmaster Plumbing & Heating and has worked on boilers, heating and gas appliances across Stoke-on-Trent since 2005. He is Gas Safe registered (reg. 220932), and these articles come from his day to day work in homes and businesses across Staffordshire, Cheshire and Derbyshire.
