Supplementary - power to central heating boiler and programmer

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.

Reply to
David WE Roberts
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If its been done to spec ALL the CH/HW electrics will be on ONE switched fused spur. USUALLY off a 13A ring or a completely separate 6A circuit.

IF......:-)

Reply to
The Natural Philosopher

If it's been wired conventionally, everything should be fed from a single supply - usually with a fused connection unit (FCU) spurred off a ring-main - so that you can isolate the whole system by throwing a single switch.

How the programmer and boiler are wired after that depends on what flavour of control system you've got. If you've got an S-Plan system, the programmer - along with the associated room and cylinder stats - will power a couple of zone valves - but will *not* power the boiler and pump directly. The zone valves have auxiliary switches which close when the valves are fully open. These have a permanent live feed (from the same FCU as the programmer) and switch on the boiler and pump when either or both zones are demanding heat.

If your system is powered from a lighting circuit, that makes it pretty unconventional to start with - so there's no telling how it's been done!

The moral is actually to get to fully understand the system when it *is* working, so that you will be able to fix it when it *isn't*!

Reply to
Roger Mills

Thanks - useful info.

The whole shooting match upstairs is powered off a fused isolating switch which goes into a wiring loom inside a big box. From this comes wiring to/from the programmer and the pump and the valve (AFAICS it is Y plan) plus at least one wire which goes off somewhere "down below". So just about everything is off one circuit. Once our guests (including cute little girl just less than one year old) have departed I will switch off the power at the isolating switch and check if there is power to the boiler. Much of the panic yesterday was because I had a house full of guests and no central heating.

So - by direct testing at the circuit breaker the CH is off the downstairs lighting. By observation I can see that everything bar the boiler is powered off this circuit. I will need to test to confirm the boiler is also powered this way.

I would like to share my thoughts with whoever wired this into the lighting circuit instead of using the spare fuse way in the main box and also put it on the lighting circuit which is much less able to cope with any initial load surge than the 13 amp. Long gone, however, before we bought the house.

Fortunately we are getting rid of the whole shooting match next year.

Cheers

Dave R

Reply to
David WE Roberts

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