The lights flicker back on after a stormy night, the fridge hums again, but the radiators stay cold. Winter storms can knock out power across Bristol and Bath, and boilers don’t always come back on their own. Most gas boilers need electricity to run, so after a power cut it’s usually a case of resetting something rather than a serious fault. Work through the checks below. If the boiler still won’t fire up, our boiler service and repairs team can come out and find the problem.
Why your boiler stops in a power cut
A modern gas boiler relies on electricity for its controls, fan, pump and ignition. When the power goes, the boiler stops too, even though the gas supply is fine. When power returns, some boilers restart automatically. Others go into a lockout state or lose their timer settings and need a hand.
Checks to make once the power is back
1. Is the power really back everywhere?
Check other appliances and lights in different rooms. Sometimes power returns to part of the street or part of your home before the rest.
2. Look at the fuse box
A power cut, or the surge when power returns, can trip a switch in your consumer unit. If one is in the off position, switch it back on. If it trips again straight away, leave it off and call an electrician.
3. Check the boiler’s fused spur
Most boilers are wired into a switched fused spur, a small wall switch near the boiler, sometimes with a red light. Make sure it’s switched on.
4. Look at the timer and thermostat
Mechanical timers lose time during a power cut, so the boiler might think it’s the middle of the night. Reset the clock to the correct time. Digital programmers may have reset to factory settings. Wireless thermostats can also lose their connection, so check the batteries and look in the manual for how to pair them again.
5. Reset the boiler
If the display shows a fault code or a lockout light, press the reset button as described in your manual. Only reset once or twice. If it keeps locking out, there’s an underlying fault.
6. Check the pressure
Look at the pressure gauge. If it has dropped below the recommended level in your manual, that may stop the boiler running.
When it’s time to call an engineer
Occasionally a power surge damages the boiler’s printed circuit board (PCB) or another electrical part. If the boiler has no display at all when the fused spur is on and the fuse box is fine, or it shows a fault code that won’t clear, it needs a Gas Safe registered engineer. Don’t remove the boiler casing or try to repair electrical or gas parts yourself.
If the heating has stopped and you’re not sure whether the power cut is to blame, our guide on what to do when your central heating breaks down covers other common causes.
Keeping warm safely during a power cut in Bristol and Bath
Power cuts in winter can last a few hours or longer, especially when storms bring down lines in more rural parts around Bath and North Somerset. To report a power cut or get updates, call 105 from any phone. We look after homes right across the area, from Keynsham to Portishead.
While you wait:
- Close curtains and internal doors to hold onto heat
- Wear layers, use blankets, and fill a flask with hot water in advance if a storm is forecast
- Never use a barbecue, camping stove or generator indoors, as they can produce deadly carbon monoxide
- Check on elderly or vulnerable neighbours
Frequently asked questions
Do gas boilers work during a power cut?
Almost all modern gas boilers need electricity to run their controls, fan and pump, so they stop working when the power goes off. The gas supply itself is usually unaffected. Once power returns, most boilers restart, though some need resetting or have timers that need the correct time setting again.
Can a power cut damage my boiler?
Usually not, but a surge when the power comes back can occasionally damage electrical components such as the circuit board. If your boiler has no display or keeps showing the same fault after a reset, get it checked by a Gas Safe registered engineer rather than repeatedly resetting it.
Why has my heating come on at the wrong time after a power cut?
Your timer has probably lost track of the time. Mechanical timers stop while there’s no power and restart from where they left off, so they end up hours out. Set the clock back to the correct time. Digital programmers may need your on and off times entering again.
Still no heating after the power’s back?
If you’ve tried these checks and your boiler still won’t work, give us a call on 01275 400 687 or drop us a message and we’ll arrange for an engineer to diagnose the fault and get you warm again.