Vaillant TURBOmax VUW 242e loses pressure?
My Vaillant TURBOmax VUW 242e loses pressure gradually through out the day when the system is filled up with the filling loop. The excess water is forced out the overflow drain outside. Checked no other internal leaks in the house and all the radiators funtion are ok. Any ideas as what is wrong.
Peter Annels, December 2010