By Combination boiler I mean one which heats water for taps etc ?instantly? and for central heating radiators - in this case a sealed system.
The actual boiler is a Green Star, a 25 from memory. ( Not ours, it is our eldest?s). The question is fairly general so the model shouldn?t matter.
Key question: If you have drained down the CH system, should you be able to still use the boiler to heat hot water?
Second question: If not: How, in normal use, does the system avoid heating the radiators when not needed when hot water only is demanded?
I am assuming there are two heat exchangers - one for hot water and one for CH, each with their own burner.
Reason for questions: during some diy, son - in - law damaged CH pipe late yesterday. The usual call home to get instructions etc. Typically, it is at (almost) the lowest point in the system but in a room stripped for refurbishment so no real harm done.
The complication is, the boiler was playing games before this, ?cutting out? heating water etc so we aren?t sure if the lack of water now is just the next step in this problem or something else.
A qualified plumber etc was booked to fix the boiler before the pipe business so I?m more curious than planning to delve into the boiler. Likewise, the damaged pipe is one which was going to be moved to fit a replacement / different style radiator by a plumber.