Just to check - I have a system boiler which provides central heating and heats a hot water cylinder.
The programmer is off and there seems to be no power to the boiler (problems with downstairs lighting circuit).
So does all the power to the system flow from one connection i.e. the boiler takes its power directly from the programmer or are the two independantly powered?
If it is all one feed then I can find where the power goes in and connect in temporarily from a ring main to get the CH working.
If the boiler and programmer are powered independantly (and both off the downstairs lighting circuit) then that is more of a challenge.
I am assuming the pump is either powered off the same circuit or off a seperate 13 amp feed. Either way I might be able to make a temporary repair.
Moral - even if it is broke don't try to fix it.