Frozen Condensate Pipe
If your Vaillant boiler is flashing with either a F28 or an F29 code, you can follow these simple steps.
During the low temperatures it's possible that your condensate pipe may freeze, if the pipe exits outside of your property.
The condensate pipe is usually a white overflow pipe, similar to one you may find on a washing machine or sink waste pipe. It allows your boiler to dispose of condensation to an outside drain via this pipe. The pipe will usually be located on the external wall outside from where your boiler is. Check out the steps below or download our hand guide below.
Download our handy guide here. (210 kB)
How to defrost your frozen condensate pipe
1. Check that your condensate pipe has actually frozen
If your Vaillant boiler is showing one of the above fault codes (F28 or F29) on the boiler’s display screen or in some circumstances you can hear a bubbling and gurgling sound coming from your boiler this could mean your condensate pipe is frozen.
2. Locate the frozen blockage within the condensate pipe
Usually your condensate pipe will be frozen on the most exposed external point, this will normally be at the end of the pipe, just below the drain or around the bend where the insulation is at its thinnest.
3. Thaw your condensate pipe to remove the blockage
You can pour warm water along the condensate pipe to remove the ice blockage. Use a suitable container like a watering can and continue the process, until either the ice falls from the pipe or until the contents of the pipe are fully drained. Please do not use boiling water as this can damage the pipe.
4. Restart your boiler once ice blockage has been removed
You should always check your boiler manual for instructions on how to reset your boiler correctly before undertaking this operation, then you should restart your boiler.
You can avoid having to repeat this process in future by insulating your condensate pipe. By insulating your condensate pipe you are reducing the risk of it freezing and blocking again in future. All good DIY stores should sell pipe insulation, this can easily be fitted with little effort.