Boiler will not restart after a power cut: what to check
Rural parts of the Mendips and the Chew Valley lose power more often than the city, and heating systems do not always come back gracefully.
Practical notes on a boiler that will not restart after an outage
- Reset the programmer clock and schedule first
- Replace wireless thermostat batteries as a matter of course
- Smart controls may need re-pairing through their app
- Oil burners may need a single reset after an outage
- Check the consumer unit and the boiler's fused spur
A boiler that will not restart after an outage: the short technical version
Programmers with dead backup batteries revert to off, wireless thermostats lose pairing, and some smart controls need a manual re-link. Occasionally an outage trips the RCD or leaves an oil burner control box locked out. Checking the clock, the schedule and the room thermostat batteries resolves a good share of post-outage calls without a visit.
Who should undertake the work
- Gas appliance work must be completed by a suitably qualified Gas Safe engineer
- Oil appliance work should be completed by a suitably qualified OFTEC technician
- Jamie Crawford Heating states both Gas Safe and OFTEC registration
Where we deal with this
Questions we get asked
- Why does my heating come on at odd hours now?
- The programmer clock has reset. Re-enter the time and your schedule and it will behave.
- Could the outage have damaged the boiler?
- Surges can damage electronics, but most post-outage faults are configuration rather than damage.
Get a boiler that will not restart after an outage looked at properly
Where this leaves you: Clock, batteries, pairing, reset. Four checks that save a callout after most rural power cuts.
Include the appliance make and model in your enquiry so the correct technical information can be checked.
Related help pages
- Leak triageWater leaking from the boiler: what is urgent and what can wait
- Pattern diagnosisVaillant F28: what changes between a first and repeat lockout
- Worcester fault codeWorcester A7: sealed system pressure fault on a Greenstar
- Oil odour diagnosisSmell of oil near the boiler: leak, spillage or normal residue
- Unvented systemsUnvented cylinder servicing and the G3 safety requirement
- Gas safetyGas tightness testing: how a suspected leak is actually checked
Services that cover this
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