My Saunier Duval Codens F30 is always depressurising and also, when it works for sometime, it shows a fault code F26 (water circulation fault). When it works, the radiators are hot, but the tap water soon becomes cold. Is it the heat exchanger?

Anthony, May 2008

Hi, i had the same fault recently but without the f26, it turned out to be sludge in the system and needed the engineer to clean or replace the blocked part, i have now got same fault a couple of months later but with f26 present. Plumber told me he put additive in when the boiler was fitted but i'm not so sure.
What did yours turn out to be?

lee, June 2008