Autumn storms bring the odd power cut, and when the lights come back on it’s easy to assume the heating will too. Often it does, but sometimes the boiler sits there doing nothing. Work through a few simple checks: is the boiler getting power, has the timer lost its settings, is it showing a fault, and has a circuit tripped? If it still won’t run, book a repair through our services page and an engineer will find out why, anywhere around Oxford.
Why a power cut can stop the boiler
Every modern gas, oil and LPG boiler needs electricity for its controls, fan, pump and ignition. When the power drops out, the boiler stops. When it returns, most boilers restart on their own, but a few things can get in the way:
- The timer or programmer has reset to default and isn’t calling for heat
- A smart thermostat has lost its connection to the boiler
- The boiler has gone into lockout because it was interrupted mid-cycle
- A circuit breaker or RCD tripped when the power came back
- A power surge has damaged a component
Check 1: Is the boiler getting power?
Look at the boiler display or indicator lights. If it’s completely dead:
- Check the fused spur switch next to the boiler is on
- Check the consumer unit for a tripped breaker or RCD
- If a breaker has tripped, try resetting it once
If the breaker trips again straight away, leave it off. That suggests an electrical fault on that circuit, which needs an electrician. Our electrical team can test the circuit.
Check 2: Has the timer reset?
Older mechanical timers lose time during a power cut, so the clock may be hours out and the heating comes on at the wrong times. Digital programmers sometimes reset to factory settings. Check the clock and your heating schedule, and set them again.
Check 3: Smart controls
Smart thermostats and their hubs may need time to reconnect to the Wi-Fi and the boiler once the router is back up. Give them a few minutes. If they still show offline, follow the manufacturer’s steps to reconnect.
Check 4: Is there a fault code?
If the boiler shows a fault code or a lockout light, look it up in your manual. Many boilers allow a single reset using the button on the front. If it locks out again, don’t keep resetting. Note the code and call an engineer.
Don’t remove the boiler casing or try to reach any internal components. Gas boilers must only be worked on by a Gas Safe registered engineer.
When to call an engineer
- The boiler has power but won’t fire
- It keeps locking out after a single reset
- The display is blank even though the fused spur and breaker are on
- There’s a burning smell, unusual noise or water leaking
- A breaker keeps tripping when the boiler is switched on
Power surges can occasionally damage a boiler’s printed circuit board (PCB), fan or pump. An engineer can test these and advise on repair.
If you smell gas
If you smell gas after a power cut or at any other time, don’t use switches or flames, open the windows, turn off the gas at the meter if it’s safe to, leave the property and call the National Gas Emergency Service on 0800 111 999.
Power cuts and older homes in Oxfordshire
Homes in villages around Witney, Thame and Bicester can be more exposed to storm-related power cuts than town centres. Older properties may also have older wiring and consumer units without modern protection, which can make tripping more likely. If your boiler is old and has started to fail after every outage, see our boiler installation page.
Frequently asked questions
How do I reset my boiler after a power cut?
First check the boiler has power and the timer settings are right. If it shows a lockout or fault code, press the reset button once, following the manual. Most boilers restart within a few minutes. If it locks out again or won’t fire at all, leave it off and call a Gas Safe registered engineer.
Can a power cut damage my boiler?
Usually not. Most boilers simply stop and restart when the power returns. Occasionally, a surge as the supply comes back can damage the circuit board, fan or pump. If the boiler won’t start or behaves oddly after a power cut, have an engineer test it rather than repeatedly resetting it.
Why does my boiler trip the electrics?
A boiler that trips a breaker or RCD usually has an electrical fault, such as a failing pump, fan or damaged wiring, or water getting into a component. It can also be a fault elsewhere on the same circuit. Leave the breaker off and get both the boiler and the circuit checked.
Heating still off after a power cut?
If you’ve tried these checks and the heating still won’t come on, give us a call on 01865 602 994 or drop us a message and we’ll get an engineer out to find the fault.
