plumbers expanding

freddiegrubb
freddiegrubb Posts: 448
edited December 2012 in The cake stop
All ye plumbers hasten here- subject- combi. boiler -can I turn off the house stop/cock & leave the htg. running, the house will be empty so no H/W draw off. Something in the back of my mind tells me that any expansion vessel fitted inside the boiler will then need to expand back into the mains system so the s/cock has to open, info. comments please.

Comments

  • desweller
    desweller Posts: 5,175
    The combi boiler won't run if there's no pressure on the cold water supply.

    The central heating circuit is completely isolated; the accumulator is there to allow the volume of the system to change (as the temperature of the water changes) without driving a big pressure change.
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  • Many thanks for your reply, I didn't type stop/fool so how come stop/cock, my original post morphed, is this some sort of BR. software protection? comments Mr. Moderator if so.
  • It is as I suspected mention c77k & it gets changed, clever system that doesn't know the diff. between a stop/fool & a stop/c77k.
  • desweller
    desweller Posts: 5,175
    Yeah, stopcock and ballcock get changed to something quite stoopid. PC fuckwittery innit.

    ETA: Ooh, looks like the filter doesn't pick it up if there's no punctuation!
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  • How fxxing ridiculous! Stopfool, thought you were taking the p1ss until the penny dropped. Yeah quite safe to do, although would question comment about pressure - it's flow that activates combi, not pressure :D
  • desweller
    desweller Posts: 5,175
    What I mean is that the boiler will probably generate an error code if there's not enough pressure on the domestic hot water side; that might cause it to disable the combustor and the pump on the central heating side. You'll have to try it to find out.

    Some heat will be transferred to the air in your now-isolated domestic hot water circuit; consider opening a tap or something to allow it to equalise pressure with the atmosphere. It probably won't change pressure much but better safe than sorry. Don't forget to put a note on your stopcock to remind you to close the tap when you get back!
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