danesmoor df 15/20 oilfired boiler,round programmer knob snapped off,,,any ideas ,where can i buy a new program unit,being as its so old???,only working on hot water at the moment,,may have to drill right through the switch and pin it if cant get one,,regards

everett kirk,leicestershire., March 2009

Sounds like an Old Horstman Emerald

Now Obsolete i'm afraid.
What my company does with these is to fit a new programmer on the wall and rewire the system

Boiler Repairman - Ipswich, April 2009