Be Prepared for Winter

It is coming to this time of year where homeowners are typically experiencing boiler and central heating issues. This includes your boiler not firing up or not working due to the freezing temperatures. If you are experiencing these issues, your condensate pipe may be frozen. Luckily, this is a quick fix that you can easily resolve yourselves without the need for a call out and pay for a heating engineer.


What is a Condensate Pipe?

Every condensing boiler will have a condensate pipe which allows the boiler to safely dispose of the acidic waste water produced from the boiler.


Where to find the Condensate Pipe?

Condensate pipes are relatively easy to find as this is typically a white plastic PCV-U pipe (similar to a waste pipe) connected to the boiler. The condensate pipe is connected underneath from your boiler and leads outside of your property into a drainage system or soakaway.


How do you know if my Condensate Pipe is Frozen?

During the winter period, you may experience having no hot water and heating which may be due to a frozen condensate pipe. There are a few steps to complete if you have a frozen condensate pipe:


1) Boiler Error Codes

Each boiler will have an error code indicating there is a frozen condensate pipe on the system which varies depending on the boiler manufacturer. The common boiler error codes include:

  • Worcester Bosch – Error code EA
  • ATAG – Error code 133 or 501
  • Vaillant – Error code F28 or F29
  • Ideal – Error code LF or F2
  • Glow-worm – Error code F1, F4, F28 or F29


2) Loud Gurgling Noise

If you have a frozen condensate pipe, you may hear an unfamiliar gurgling sound coming from the boiler. This is due to the water running through the external pipe being frozen over from the cold temperatures, creating a blockage in the pipe.


The sensors in the boiler will automatically detect this blockage and prevent the boiler from operating which is a safety precaution that prevents further damage to the boiler. For safety reasons, the boiler will not reignite or turn on until the blockage is removed from the condensate pipe.


3) Checking your Condensate Pipe

Upon close inspection, you may see icicles forming on the condensate pipe which suggests that you have a frozen condensate pipe. You will need to thaw the condensate to remove this blockage.


How to Safely Thaw your Frozen Condensate Pipe?

Note: You should not attempt to thaw the condensate pipe if you cannot easily reach this from the ground level. Be aware that any water that has fallen from the pipe may freeze over making the pathways a possible slip hazard. 


  1. If you are confident to thaw your frozen condensate pipe, you will need to first prepare some water at between 60-70 degrees Celsius. Please do not use boiling hot water as this will damage your pipe.
  2. Pour some jugs of warm water onto the external condensate pipe to melt the ice blockage within the pipework.
  3. Continue until you can see ice fall from the pipe and until all of the contents within the pipe are fully drained out.
  4. If the temperature is below -2 degrees Celsius, you will need to wrap a hot water bottle onto the condensate pipe to melt the ice blockage. This is because the water poured onto the condensate pipe will eventually freeze due to the cold temperatures. Wrapping the condensate pipe with a hot water bottle will prevent another frozen condensate pipe.
  5. Restart the boiler by pressing and holding down the reset button for 10 seconds or until the boiler restarts itself. This is shown on the front of the boiler panel.
  6. Once the boiler is switched back on, you should not have any boiler error codes and your hot water and heating should operate as normal.
  7. If the boiler error code is showing again, double-check that the condensate pipe is still not frozen and repeat the process.


For more information on how to resolve the frozen condensate pipe issue, please watch the below video:



How to reduce the risk of a Frozen Condensate Pipe?

  • Turn the heating control on the boiler to the maximum number.
  • Insulate the external pipework to prevent the waste water from freezing and blocking in the future.


To upgrade your external pipework, please contact Rudkin & Herbert Ltd. to arrange a survey and inspection on your property.