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How to safely thaw a frozen pipe

here are a number of reasons why you could be struggling to get hot water. In the winter months, there’s a huge risk of your condensate pipe freezing, which could affect your hot water by preventing wastewater from being disposed of down the drain. It could also be a reason why your heating isn’t working and why your house is so cold.

We look at how to remedy the problem before a repair is needed. You want to act quickly to get that water flowing, without compromising on safety. Consult our guide carefully to prevent burst pipes or risk of fire.

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How to check for frozen pipes

Give your boiler a quick inspection. The tell-tale signs of a frozen condensate pipe are flashing lights,  a noisy boiler when it’s switched on, and the front display should read as ‘blocked’.

Once you have identified that your pipe is indeed frozen, you can proceed with locating and then thawing to get the whole system working efficiently again.

Locate your frozen boiler pipe

It’s time to brave the cold and go outside to find your condensate pipe – it’s usually a white or grey plastic pipe coming out from the back of your boiler to the outside wall of your property.

When installing a boiler, there’s always a large amount of piping that is exposed to outdoor conditions. When the weather turns cold, the pipe could get blocked due to the pipe freezing.

The condensate pipe is an important part of your boiler as it discharges wastewater vapour from the system. If the pipe is blocked, it will force your boiler to shut down for safety reasons.

How to unfreeze pipes

1. The easiest way to thaw frozen pipes is to put it in contact with warm water. A couple of jugs of warm water poured over the exterior of the pipe will melt the ice within.

2. Make sure you don’t use boiling hot water, as the rapid change of temperature could crack the plastic pipe. If you don’t have a jug on hand, feel free to use a hot water bottle or warm flannel to thaw frozen pipes. Alternatively, you could use a hairdryer, or apply electrical heating tape directly to the pipe; this distributes heat along the pipe evenly. 


3. You should also start the thawing near the pipe’s faucet if possible, then towards the blockage. This means that your pipe is less likely to burst as the pressure won’t be as intense.

4. If the frozen pipe is hard to reach, there are a number of ways to still thaw it yourself. You can try turning the central heating up in your home using your thermostat for the ice to melt. 

5. Alternatively, you can use an infrared lamp as its heat may be able to penetrate the frozen pipe.

6. If you are unable to thaw the pipe yourself after trying all of the above, or if the pipe bursts, contact a professional. We can connect you to reputable local gas engineers.

DO NOT ever try to thaw the condensate pipe with an open flame!

How long does it take for condensate pipes to thaw?

Using one of the DIY methods we have described, it usually takes between 30-40 minutes to unfreeze your condensate pipe and get your hot water running again.

Will the pipes thaw on their own?

The simple answer is yes, but the process can take days. The longer you leave them to thaw, the more likely that the pressure build up will cause them to burst. So, it’s recommended that you intervene as early as possible.

What to do if your water pipe bursts?

  1. If a pipe bursts, you must locate the stop valve which controls the water supply entering your property and turn it off immediately. The most common location for the stop valve will be under a sink and will normally close by turning it clockwise.
  2. Then switch off your immersion heater and central heating boiler, before opening all hot and cold taps to drain any remaining water.
  3. Switch off your electricity if there’s a chance that water could come into contact electrical wiring or parts.
  4. Call out a plumber to fix your pipework and make sure that your boiler is inspected by a qualified Gas Safe Engineer.

Reset your Boiler

With the frozen blockage now melted, all that needs to be done is for you to reset the boiler. Your central heating system should now be working as intended.

More often than not, resetting a boiler is just a case of pushing a button. However, the process can depend upon the make and model of your appliance. If your boiler doesn’t have a simple reset button, then consult your manual to see exactly what steps to take.

Call a Boiler Plan expert 

If you can’t get your boiler working after you’ve thawed the condensate pipe and reset the system, it may be that it has additional faults that need looking at.

If this is the case, it’s best to call a Gas Safe engineer as soon as you can.

Boiler need some TLC?

Let our experts take care of it with an emergency repair

If you can’t get rid of that annoying boiler noise, you may need to seek help from an engineer.

Our Boiler Plan Gas Safe experts will point out any work that needs to be carried out, they'll also provide a fixed price repair quote.

With our 24 hour emergency repair and 95% first time fix rate, we’ll have your heating up and running again in no time.

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How to prevent frozen pipes

To prevent this issue from arising in the future, there are a few steps you can employ:

  • Seal up any cracks or holes efficiently.
  • Fit extra insulation throughout your home.
  • Keep your heating on for longer (use a timer to have the optimum warmth at lower price).
  • Disconnect garden hoses from outdoor faucets.
  • Let your faucets drip/trickle slightly. Alternatively, turn your taps on and off regularly.
  • Keep doors within home open to allow heat flow.
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