question for org plumbers and heating engineers

[timwilky]

My lad has a traditional heating setup. cold water header in loft, hot water storage tank in bedroom and a Baxi boiler downstairs.

The other day he complained the boiler had failed and I got a friend of a friend gas fitter in to replace the gas valve.

Now he says the central heating comes on with the hot water, I have just been up and confirmed, there is only the hot water on. the digital controller confirms only hot water, yet the pump is running, turn off the hot water and the pump stops.

How should all this be wired, I assume the pump is wired in series with the room stat, so when central heating is on, power is always to the room stat, temperature drops, stat switches power through to pump.

So I have told him till wait till weekend, I will go up with screwdrivers, torch and meter. If anyone in the know can confirm my basic guess as to how the pump should be wired it would be appreciated.

[Bibio]

control valve jammed burgerd. hot water should come on with CH but hot water should be able to go on its own. from what i remember.

[Dicky Ticker]

Tim,I just had a similar problem with mine and it was the throw switch beside the tank which differentiates whether you want water heating or radiator heating

[dirtydog]

3 port valve would be my first port of call (see what I did there). You may be able to get away with just changing the motor as it saves draining any of the system down and it's a little bit cheaper as well.

[Bluefish]

tim the pump would run with hot water on, unless it is a gravity system, if when only hot water on the htg comes on then the zone valve, the one with the lever that moves peeps were on about is buggered, you may be able to just change the motor in the zone valve depending on type, hth

[Bluefish]

damm you dirty dog, see what i did there eh eh ;)

[dirtydog]

sorry BFM you're just toooo sloooow! ;)

Tim you'll either have a 2 port valve like this...
http://www.screwfix.com/prods/31480/Plumbing/Central-Heating-Controls/Honeywell-V4043H-2-Port-Motorised-Valve

or a 3 port like this...
http://www.screwfix.com/prods/31421/Plumbing/Central-Heating-Controls/Honeywell-V4073A-3-Port-Motorised-Valve


you can normally get away with just swapping the motor which looks something like this...
http://www.screwfix.com/prods/28670/Plumbing/Central-Heating-Controls/Drayton-Synchronous-Motor

[timwilky]

Cheers guys, I will grab a motor in the morning as the lowest cost option and give it a go. I never would have thought it would be that.

[Dicky Ticker]

Tim,try holding the operating lever over by hand a couple of time as they can become sticky and you may,may just get away with freeing it up.[I didn't]



These are the words of a diesel eng. not a heating engineer:)

[dirtydog]

Tim,try holding the operating lever over by hand a couple of time as they can become sticky and you may,may just get away with freeing it up.[I didn't]



These are the words of a diesel eng. not a heating engineer:)


But for the sake of less than £15 it's worht just changing the motor

[Dicky Ticker]

DD--You know my upbringing.:)

[dirtydog]

Yeah, thought of that just after I posted. Lol

[Bluefish]

or if you are really tight you can put it in the manual position and leave it there.