In an earlier contribution to this discussion,
altheman alan@ford50(no spam).freeserve.co.uk wrote:

so then...if i switch on just central heating..it will either ..work
or not work?.....and i cannot do any damage to system..that
correct?...sorry about all this but i really have no idea .thanks
yet again in advance

You are correct in the above assumption.

Would you care to elaborate on exactly what you're trying to achieve, and on
what prompted you to ask the initial question?
--
Cheers,
Set Square
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