Many thanks for prompt replies. doitall - My first instinct was to fit a new one, but they seem to be obsolete. Not sure which model it is - hence not sure which digital unit would be compatible.
weareleeds - thanks for the suggestion, I will certainly try it. As there are no screws...
I have an old Landis & Gyr mechanical controller connected to my central heating and hot water systems. A couple of days ago I noticed that the heating remained on continuously, and when I looked at the controller I noticed that the rotating dial was stuck at the number 2 (off) selector and...