Hi guys I recently had a new bathroom fitted and while the plumber was in I asked him to change the 3 port valve as it was a bit dodgy previously. Since he has changed it the heating controls work back to front so I have to turn hot water on to get central heating and central heating on to get hot water and he is saying it' a fault further down the line but it worked perfect be for he fitted the new valve any ideas or suggesting welcome Chris
It would seem whoever wired it has used the green/yellow as a line wire, which although not strictly against regulations (as long as over sleeved) it raises the question of how the items connected are earthed? The regulations require an earth to be provided even if it is not used with fixed wiring. Looking at the 5 wires from the motorised valve we can say where they should be connected. Green/yellow is as one would expect earth. Blue is neutral. Grey is hot water off. However grey seems to be linked to earth, that's not right. Orange is hot water on. And on my diagram it says brown/white is call for central heating, I would assume in your case white. So it would seem there has been some confusion as to earth and green/yellow wires used for other functions. The error is use of three core instead of 4 core cable, and lack of sleeving where green/yellow or blue are used as line wires. It would seem likely this was an error with orignal installation, however personally I feel the last person to work on the system should have sleeved the cables even if they did not renew the three core for 4 core.
Hmmmm the 3 port head the chap changed I think is a Honeywell V4073A in fact I'm sure it is. The orange wire fires the boiler, and if not a system boiler it would also be connected to pump I would think MGW.
Yes the installation is the same as orginal because I have a drawing of where the wires went before he changed the valve but I never had the issue of the controls working backwards before
Yes, should be able to remove the head and turn it round. But I agree, it worked ok before the guy fiddled with it. It’s not something “further down the line”. Get him back to fix it.
There are two plans using three port valves W heats hot water then central heating and Y does both together, the latter has a mid position. Today most central heating systems have it all built into boiler, so don't see the Y plan that much, I would think yours is Y plan from wire colours, but if wrong valve fitted that could be wrong. Last image is same as second but shows how it works, Orange powers the boiler either direct from cylinder stat or from the motorised valve, the room thermostat does not directly supply boiler, but moves the valve then valve micro switch works boiler. Without power to grey hot water satisfied wire once water is hot it will not work, it seems looking at your picture it is connected to earth? Although just one micro switch is shown, there are I think three micro switches in the valve, the other two hold the valve mid way when required, however not all valves are the same, they all have three positions but how they select them internally changes. So maybe the original valve would work with incorrect wiring and new one will not, however it is up to guy fitting it to correct any errors does not matter if his error or guy before him.
He has been back twice but said it' a fault further down the line and would need a sparky to come and take a look ? What do you mean by turn it around the motorised head ?
Could be the guy before him I had a new boiler 2 years ago and he had some issues with wiring also blew the time switch up which he replaced but has been working fine until this valve was fitted
I am curious! I thought it was against regulations to use an earth wire for anything other than an earth, even if it is over-sleeved? I have always avoided this like the plague because I personally think its a bad idea to use an earth for anything other than an earth, but I always thought it was illegal as well. There seems to be at least two occasions where the wrong cable has been used ( unless my eyes deceive ). I am afraid that I could not leave it like that.
If he can't do the job, and he has taken on the work it is up to him to sub contract to an electrician or heating and ventilation guy who can. It now needs some one who is use to working with Y plan central heating, working out what some one has done wrong is a lot harder than doing the job in the first place. My oldest daughters first house had this system, some one had fiddled with it, a micro switch had failed, and to keep it running the bleed lever had been latched open, son-in-law cleaning caught lever and unlatched it. I spent most of the day trying to work out what had happened, it was a real nightmare, I was looking for something he had done, not a faulty valve head, but as a result I know not the easiest system to work on. So you need an old heating engineer who will have likely seen same fault many times and can fix it in 15 minutes, and electrician even a good one, if he has not worked on such an old system could take all day to work out what he has done wrong.