british gas just replaced the valve resulting in no hot water (hot rads), I call them again the next day they come out he said everything is ok but valve might be sticking because of sludge??? and recomends that he powerflush the system at a cost of £600,
I call them again but this time they say they will not come out untill i agree to the powerflush (sounds like blackmail to me) Anyway ive tried all switch combinations on the programmer but the valve will not move back to position a (hot water) the only way it will move is to disconnect the grey wire and then it freely moves to position a (without any sludge slowing it),any ideas would be very welcome.

BRAMBLESTONE, April 2007

The grey wire is only live when there is no call for hot water, i.e. either the cylinder stat is satisfied or the programmer is not calling for hot water. This sounds like a wiring fault to me.

Ed the sparky, August 2009

possibility that the programmer relays are faulty or there are loose wires at either the back of programmer or loose wires in the junction box by the mid position valve

notman69, May 2007

If the heating is working, then it's not sludge. If you dis-connect the grey wire and the valve moves, then it's wired incorrectly.

If they wired it back in, it's their problem.

George, April 2007

Paul the gas man

your correct, just read it back and noticed grey is live.

hi-spec plumbing, April 2007

get british gas back. insist that the technical service manager is sent and that if this is not resolved straight away you will go to trading standards. the engineer has not fitted the valve correctly by the sound of it and should return and sort it out. by the way grey is live when there is no demand from the clock or cylinder stat.

Paul the gas man, April 2007

http://www.tlc-direct.co.uk/Technical/DataSheets/Horstmann/Pics.pdf

try this diagram 1 is any help. grey is only live when cylinder stat calling for water. when water hot enough in cylinder the tank stat closes circuit so grey wire becomes dead. orange is switch live, white to room stat. then live & neutral

hi-spec plumbing, April 2007

Hi, yes it is drayton it is exactly the same as one for sale on ebay. There always seems to be power to the gray wire even when everything is switched off. Is this normal? From what info i have found at some point the spring should be able to return the valve to the hot water. I can't see that it can with the wiring that bg has done. Is there an idiots guide to wiring it up or anything I could try to prove there is a wiring problem.
Thankyou.

bramblestone, April 2007

just read somewhere on the net it appears to be a drayton valve they use

hi-spec plumbing, April 2007

sounds like a valve with there own name on they do it with boilers have a basic brand of boiler but with there casing/name on, but i would put it down to a wiring problem. hard to say with out seeing. but nothing i like better than bg proven wrong.

hi-spec plumbing, April 2007

Thanks for your quick response. I can't see a make on the valve only a number BGMVSP-23 and a british gas label. he changed the old one because it kept clicking and he said it was obsolete which is why he fitted this new one. There was no mention of sludge then. sorry I can't provide more info.
I would really like to prove that it is faulty wiring as I really think a power flush is not necessary.
Thankyou.

bramblestone, April 2007

what make of valve is it they are all wired different ? sounds to me as it is wired wrong. as for power flushing bg are always over priced on that. if you are a average 2/3 bed house we and most plumbers powerflush them for about £400. best way is check your f/e tank in loft (small one) for sludge or silt in the bottom, it will take some kind of sludge to stop a new valve.

hi-spec plumbing, April 2007