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Quick answer
If your boiler breaks down in winter, first check the power, the gas supply, the pressure gauge, the thermostat and timer, and whether the condensate pipe has frozen. Reset once using the manual. If it still will not work, call a Gas Safe registered engineer and keep warm with electric heaters, never a gas cooker or outdoor heater.
Key takeaways
- Check power, gas, pressure, controls and the condensate pipe before calling.
- Reset the boiler once only, following the manual.
- Heat one room with electric heaters; never use a gas oven or outdoor heater indoors.
- Give the engineer the make, model, fault code and pressure reading.
A boiler that stops in the middle of a cold snap is stressful, especially with children or older relatives at home. The good news is that a fair share of winter breakdowns come down to something simple you can check in a few minutes. If it is a genuine fault, a little preparation keeps the house safer and warmer and helps the engineer fix it on the first visit.
What should I check before calling an engineer?
Work through five quick checks: is there power to the boiler, is gas reaching the house, is the pressure within range, are the thermostat and timer calling for heat, and has the condensate pipe frozen? These account for many of the no-heat calls engineers get in winter, and none of them involve opening the boiler.
| Check | What to look for | What you can do |
|---|---|---|
| Power | Blank display, no lights | Check the fused spur switch next to the boiler and your fuse box |
| Gas supply | Gas hob will not light either | Check the meter valve is open and a prepayment meter has credit |
| Pressure | Gauge below the manual's range | Top up via the filling loop, following the manual |
| Controls | Thermostat display blank or timer wrong | Replace batteries, reset the clock after a power cut, turn the thermostat up |
| Condensate pipe | Gurgling, lockout code, sub-zero night | Thaw the outside section with warm, never boiling, water |
If the pressure is low, our guide on repressurising a combi boiler explains the steps. For a frozen pipe, see how to thaw a frozen condensate pipe safely.
Should I reset the boiler?
Yes, once, using the reset procedure in your boiler manual, after you have done the checks above. A reset clears a lockout caused by a temporary condition, such as a frozen condensate pipe that has since thawed or a brief interruption to the gas supply. If the boiler locks out again, stop resetting and call an engineer.
Resetting over and over will not fix an underlying fault and can make it harder to diagnose. Write down the fault code shown on the display before and after the reset, as it tells the engineer a great deal.
Gas smell or carbon monoxide alarm: Do not reset the boiler or touch electrical switches. Turn off the gas at the meter if you can do so safely, open doors and windows, get everyone outside and call the National Gas Emergency Service on 0800 111 999. Never remove the boiler casing to look for a fault.
How can I keep warm safely while I wait?
Heat one room well rather than the whole house badly. Use portable electric heaters, such as oil-filled radiators or convector heaters, in the room you are using, and close its door and curtains to keep the warmth in. Layer clothing, use blankets and hot water bottles, and have regular warm drinks and hot food.
Some things to avoid, because they cause fires and carbon monoxide poisoning every winter:
- Never use a gas cooker, hob or oven to heat a room.
- Never bring patio heaters, camping stoves, barbecues or garden gas heaters indoors.
- Do not leave electric heaters on overnight or unattended, or near curtains, bedding or drying clothes.
- Plug each heater directly into a wall socket rather than a crowded extension lead.
- Keep a working carbon monoxide alarm in any room with a fuel-burning appliance.
The National Gas emergency service advice covers what to do if you suspect a gas escape, and our own guide on what to do if you smell gas sets out each step.
How do I get hot water without the boiler?
It depends on your system. If you have a hot water cylinder, it may have an electric immersion heater you can switch on to heat water independently of the boiler. An electric shower will also still work. With a combi boiler there is no stored hot water, so a kettle and an electric shower, if you have one, are your options.
Keep an eye on your pipes while the heating is off in freezing weather. Open the loft hatch and cupboard doors under sinks on outside walls to let some warmth reach the pipework, and know where your stopcock is in case a pipe bursts.
What information should I give the engineer?
The more the engineer knows before they arrive, the more likely they are to bring the right parts and fix it first time. Have this ready when you call:
- Boiler make and model, from the data label or manual.
- The fault code on the display, and whether it changes after a reset.
- The pressure reading, cold.
- What happens: no power, tries to light and fails, heating works but no hot water, noises, leaks.
- Roughly how old the boiler is and when it was last serviced.
- Whether it is still under a manufacturer's warranty.
- Whether anyone at home is elderly, very young, unwell or disabled.
If the boiler is under warranty, contact the manufacturer first, as a repair by a different engineer may not be covered. If you rent, report the breakdown to your landlord or letting agent straight away.
Getting an emergency boiler repair in Staffordshire
If the checks have not worked and you are without heating or hot water, our emergency boiler repair service is there to help. Repair and diagnosis visits are £90 per hour, and we will tell you what we find before any work goes ahead.
We cover the whole of Stoke-on-Trent and further afield, including boiler service in Burton upon Trent and boiler service in Lichfield. Call 07896 677083, and have the details above to hand.
Frequently asked questions
How long can a house go without heating in winter?
There is no set limit, but the colder it is and the longer the heating is off, the higher the risk of frozen pipes and of people getting too cold. Heat at least one room, keep an eye on vulnerable people and get a repair booked as soon as possible.
Will my landlord have to fix a broken boiler quickly?
Landlords are responsible for keeping the heating and hot water in working order, and a breakdown in winter should be treated as urgent. Report it in writing as well as by phone. Citizens Advice and GOV.UK explain tenants' rights in more detail.
Can a boiler break down because it was not serviced?
A missed service does not cause a breakdown on its own, but it removes the chance to spot worn parts, blocked condensate traps and pressure problems early. Many winter breakdowns involve faults a service could have picked up months before.
Should I switch the boiler off at the mains while I wait?
If it has locked out and you are waiting for an engineer, it can be left as it is. If it is leaking water near electrical parts or behaving strangely, switch it off at the fused spur and turn off the gas at the meter if you are concerned.
Sources and further reading
Gasmaster Plumbing & Heating has served Stoke-on-Trent since 2005. Every article is written by our Gas Safe registered engineers (reg. 220932) from day to day work on boilers, heating and gas appliances across Staffordshire, Cheshire and Derbyshire.
