Winter boiler guide · Glasgow
Is your condensate pipe frozen?
Woken up to a cold house and a boiler that won’t fire? If it’s below freezing outside, check the condensate pipe before you book a repair. It’s one of the most common reasons a boiler stops in a cold snap.
The good news is you can usually get it going again yourself in a few minutes, with nothing more than a kettle of warm water.
At a glance
What is a condensate pipe?
Almost every modern boiler is a condensing boiler. It squeezes extra heat out of its waste gases, and that makes water, called condensate. The water is mildly acidic, so a small plastic pipe carries it away to a drain.
In lots of homes that pipe runs outside, where it’s open to the cold. On a freezing night the water in it turns to ice and blocks it. The condensate has nowhere to go, so the boiler shuts itself down to stay safe.
How do you know it’s frozen?
Start outside. Frost on the pipe, or ice at a joint or the open end like in the photo above, means it’s frozen. Inside, you’ll usually notice one of these.
Boiler stopped
It’s freezing outside and the boiler has suddenly stopped.
Fault code
A fault code or a flashing light on the boiler.
Gurgling
A gurgling noise from the boiler or the pipe.
Fires, then cuts out
The boiler tries to start, then stops again.
How to thaw a frozen condensate pipe
You’ll need a kettle of warm water and a few minutes. Wrap up warm, and take care on icy ground.
Find the pipe
Look under your boiler for a white or grey plastic pipe. Follow it through the wall and down to the drain outside.
Find the ice
Check the outside run. Ice usually builds up at the bends, the joints and the open end.
Pour warm water over it
Boil the kettle and let it cool for a while, so it’s warm, not boiling. Pour it slowly over the frozen part. It can take a couple of kettles.
Reset the boiler
Once the ice has cleared, press the reset button (your manual shows where it is). Give it a few minutes and it should fire up.
No kettle to hand? A hot water bottle or a heat pack held against the pipe works too.
Stay safe
- Never use boiling water. It can crack the pipe and scald you.
- Don’t climb ladders in icy weather. If the frozen part is high up, call us instead.
- The water you pour can freeze on the ground, so watch your step.
- Never take the cover off your boiler. Only a Gas Safe registered engineer should work inside it.
- If you can smell gas, call the gas emergency line on 0800 111 999 straight away.
How to stop it freezing again
If your pipe freezes every winter, it’s worth fixing for good. Our engineers will look at how yours is run and recommend the simplest fix for your home.
Best fix
Move the pipe inside
Rerouting the pipe to a drain inside your home takes it out of the cold completely. Where it’s possible, it’s the best way to stop it freezing.
Fit a wider pipe
A wider pipe on the outside run takes much longer to freeze and block.
Keep the outside run short
The less pipe there is outside, the less there is to freeze.
Insulate it
Weatherproof lagging helps the pipe hold on to a little warmth on cold nights.
Add trace heating
A low-power heating cable along the pipe stops ice forming in a cold snap.
Your annual boiler service is a good time to get the pipe checked before winter sets in.
When to call us
Give us a call if you can’t reach the pipe, can’t find the ice, or the boiler still won’t restart after you’ve thawed it. It could be a different fault, and our boiler repair team can track it down.
If you’re on Home Comfort, our boiler care plan, you can call, video call or WhatsApp us and we’ll talk you through it.
Boiler stopped in the cold?
Our local engineers cover Glasgow and the surrounding areas. Get in touch and we’ll get your heating back on.
More help from Glasgow Boiler Experts
See all our case studies or find out about boiler repairs in Glasgow.
