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How to get your boiler ready for winter
Test the heating before the cold arrives, check the pressure, bleed the radiators, protect the condensate pipe and get it serviced. Ten minutes now can save a cold week in January.
- 1service a year, by a Gas Safe engineer
- 1 to 1.5bar pressure, cold
- 12°CWorcester’s setting if you’re away in a cold spell
10minutes of checks
A lot of the breakdowns we see in winter could have been spotted in September. A boiler that’s sat idle all summer gets switched on in the first cold snap, and that’s when problems show up, at the same time as everyone else’s.
Here’s a simple checklist. Most of it you can do yourself in ten minutes.
The checklist
Do it before the first cold snap.
- Run the heating for an hour to check it works
- Check the pressure is around 1 to 1.5 bar when cold
- Bleed any radiators that are cold at the top
- Top the pressure up again after bleeding
- Insulate the outside condensate pipe
- Test your carbon monoxide alarm and check its date
- Check the timer, especially after the clocks change
- Book your annual service if it’s due
If radiators are still cold at the bottom after bleeding, that’s usually sludge, and it needs an engineer.
Included on every Home Care plan.
Annual service
Protect against frost
Fife winters are hard on condensate pipes.
The condensate pipe
The white plastic pipe outside is the one that freezes. Worcester says you can insulate it yourself with weatherproof pipe lagging, and a cover over the drain helps too. If it freezes every year, it can often be rerouted inside.
Going away
Don’t switch the boiler off. Its frost protection only works when it’s on. Worcester’s advice for a home left empty in cold weather is to leave the programmer on constant and the room thermostat at 12°C. A smart thermostat’s frost or holiday setting does a similar job. If the house will be empty for a while, check your home insurance conditions too.
Pipes in the loft
Insulate water pipes and tanks in the loft. It cuts the risk of bursts in a hard frost.
Condensing boiler
Know where these are
Before you need them in a hurry.
Your stopcock
Usually under the kitchen sink. Test that it turns, so you can stop the water if a pipe bursts.
Your gas valve
On the pipe by the gas meter. A quarter turn so the handle is across the pipe turns the gas off.
If a pipe freezes or bursts
Turn off the stopcock, switch off the heating and open the cold taps to drain the pipes. Scottish Water says leave the hot taps shut, as a hot water cylinder could collapse. Then call a plumber.
If you smell gas
Open windows, turn the gas off at the meter, no switches or flames, and call 0800 111 999.
What should I do next?
- Not serviced this yearBook a service
£120 including VAT.
- Pressure below 1 barTop it up
Our guide shows how.
- Radiators cold at the topBleed them
Then top up the pressure.
- Want it all looked afterHome Care
Service included, from £11 a month.
Common questions
When should I get my boiler serviced?
Once a year, by a Gas Safe registered engineer. Late summer or early autumn is ideal, before the heating’s needed every day, but any time is better than skipping it.
Should I leave my heating on when I go away in winter?
Yes, on low. Your boiler’s frost protection only works when it’s switched on. Worcester suggests the programmer on constant and the thermostat at 12°C for an empty home in cold weather. A frost setting on your thermostat does a similar job. Check your insurance if the house will be empty for a while.
How do I stop my condensate pipe freezing?
Insulate the outside section with weatherproof lagging and keep the end clear. In a severe cold snap, turning the boiler’s heating temperature up for a few days helps. If it freezes every winter, ask about rerouting it inside.
What pressure should my boiler be at?
Around 1 to 1.5 bar when the system is cold for most boilers. Check your manual for your boiler’s exact range.
Do I need to bleed my radiators every year?
Only if they’re cold at the top. Check them when you first put the heating on, and top the boiler pressure up afterwards, because bleeding lets some water out.
What should I do if a pipe bursts?
Turn the water off at the stopcock, switch the heating off and open the cold taps to drain the pipes. Scottish Water says leave the hot taps shut, because a hot water cylinder could collapse. Keep water away from electrics, and call a plumber.
Related pages
Sources: Worcester Bosch, frozen condensate; Vaillant, controls and frost protection; Scottish Water, frozen pipes; SGN, be winter ready. Checked 2 November 2026.
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