Check the pipes from your boiler especially the condense drain. This can be lagged or made larger to prevent freezing.
Pipe lagging is a special type of insulation fitted around water pipes. It keeps heat within the pipes
It’s useful for saving energy as well as preventing pipes from freezing and bursting. Lagging also prevents condensation forming on cold pipes in loft spaces.
Need more advice? Contact Top Plumb heating engineer Hemel Hempstead.