Frozen condensate pipes in Great Barr, Birmingham

Building regulations state that all replacement boilers installed after April 2005 must be condensing boilers due to their energy saving credentials. This, coupled with some very cold winters in the UK has resulted in a number of people experiencing boiler breakdowns due to frozen condensate pipes. 

Building regulations presently allow boiler condensate pipes to be routed outside which, in hindsight, may not have been such a good idea. 

However, as a large percentage of householders have an external condensate pipe, MasterGas have put together some tips and information to help if your pipe does freeze, and advice on how to prevent it happening again this winter. 

Symptoms of a frozen condensate pipe 

How do you know if your boiler condensate pipe is frozen? There are a number of things you can check including: 

  • Have external temperatures been below freezing for some time? 
  • Are there gurgling or bubbling noises coming from the boiler? 
  • Are there any warning lights or error codes displaying on the boiler control panel? 
  • Has the boiler shut down i.e. there is no hot water or central heating? 

It is worth checking your boiler manual at this point to see if you can identify any of the error codes or warning lights on the boiler as this may help to confirm any diagnosis. 

Thawing a frozen condensate pipe 

Once you are certain you have a frozen condensate pipe, you will need to thaw the pipe. This will involve: 

  • Locate your external condensate pipe (usually a grey, white or black plastic pipe that you can trace outside from your boiler) 
  • Identify where the blockage is in the pipe if you can. You may find that one section of the pipe feels colder where the ice has built up. You will usually find this is the most exposed part of the pipe. 
  • Thaw the pipe with either a hot water bottle, heat pad or warm (but not boiling) water. You can use a watering can to pour the warm water over the pipe or sit the heat pad/hot water bottle on the pipe (if possible). 
  • Once the ice has completely cleared you can restart your boiler. 
  • If you are unsure how to do this, please refer to your boiler manual or contact us at MasterGas. 
  • If you are unable to restart the boiler, it may have another problem so you will need to call us to investigate. 

Preventing your condensate pipe freezing in the future 

Prevention is always better than cure, particularly when a frozen condensate pipe is only going to occur when it is freezing outside and you really need your central heating! We can help you with a number of ways to stop your condensate pipe freezing? 

  • You can have the pipe replaced with a larger diameter pipe that's less likely to freeze. The minimum diameter should be 32mm and make sure it is insulated. 
  • If possible, re-route the condensate pipe indoors to prevent exposure to particularly cold weather. However, if you do re-route the pipe and it is likely to route through an unheated room or area, it is still advisable to insulate the pipe. 
  • If your condensate pipe is outside you can buy insulation to help protect it against freezing but this may not be enough to prevent freezing in really cold weather. 
  • Make sure your external condensate pipe has a minimum number of bends and there is a sloping fall for the entire length of the pipe to prevent water sitting in the pipe and freezing. 
  • We can also supply and fit heating devices and alarms designed to prevent ice building up in your condensate pipe. 

Safety First! 

If you are having problems with your boiler and you are unsure as to what the problem is, you should speak to us and we will gladly help you out with any advice needed. You should not attempt to repair the boiler yourself.

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