View Single Post
  #3   Report Post  
Posted to uk.d-i-y
Roger Mills[_2_] Roger Mills[_2_] is offline
external usenet poster
 
Posts: 4,120
Default Supplementary - power to central heating boiler and programmer

On 12/11/2011 17:33, David WE Roberts wrote:
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.


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*!
--
Cheers,
Roger
____________
Please reply to Newsgroup. Whilst email address is valid, it is seldom
checked.