DIY Doctor UK DIY Forums

Hi all, newbie and a bit of a novice so please be gentle! ;)

Ok so last year I had a new Ideal Logic Heat 15 boiler installed on a discount Govt scheme.
To cut it short, the company they sent were a right shower of shit*s and it was a right b@llache. I was messed about with appointments, useless plumbers/sparkys etc.
The boiler itself is fine but ever since installation I've never had hot water from it, only if I put the immersion on.

I tried and failed to get them to return to fix it and I just gave up (endless lost work days waiting in for no shows) so I carried on with the immersion, but of course it's quite expensive.

But now I need it sorting. I'm quite handy with water plumbing (obvs not gas) and my partner is very knowledgable with elecs, so we're wanting to DIY it if poss as we're skint!

It's got a Honeywell V4703 MPV which was fitted at the time of the boiler installation - maybe the problem? The lever is very resistant on it when trying to move to manual which I think means it's ok?

It's a Y plan system and there's an F&E tank and the big cold water tank in the loft. (hope I got the terminology right!)

So, is this wiring correct? (front cover was broken by installer too (didn't notice at the time), although we do still have it and usually have it taped on.

The lower white cable is from the Wilo Yonos Pico pump (newly fitted by me and partner last weekend, although we wired it from the old pump, not from the junction box), the higher one is from the Sentinel filter (also fitted at boiler install) and the black is from the Honeywell.

Thanks for any help, and of course please say if you need any more info. :)

It would take some time to work out what you have even with a meter, with the Y plan domestic hot water is default, valve half way gives both, and all the way central heating only.

So white wire to valve should make valve go half way, the grey wire will make valve go all the way, so for domestic hot water grey should not be line.

Clearly electrics are dangerous, so care required, never work alone, better if you don't work live.

So if it were me, I would switch off power, move grey wire from where it is and put it in a unused terminal on the block, turn it all back on and see if you get hot water, when central heating also running. If so then you know plumbing is OK it is wiring, if not it has a plumbing fault.

As a P.S. earth wires should not be over sleeved and used as a live wire, so I can confirm a load of cowboys installed it.

Also with grey wire disconnected, you will not be able to switch off domestic hot water, so only a temporary thing to test.

Since the motorised valve has fixed colours, that is the way to work out what is what.
Blue = Neutral
Green/Yellow = Earth
White = Central heating
Grey = No domestic hot water (default is on, grey turns it off)
Orange = Feed to boiler and pump

Thank you, that was very helpful and all sorted now. Cheers! :)