Decommissioning old wired thermostat

24 Jan 2023
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United Kingdom
Hiya. Hoping someone might be able to help! Over the weekend I’ve managed to successfully install the hive system which is working great. However, as a temporary fix I’ve left the old wired thermostat in place and turned it up to maximum temp. Hoping to get rid of our old wired stat and put up the nice new hive Stat in place of the hole in the wall.

Did some research and felt like I had the right idea re removing the old stat from the wiring center but would appreciate advice from someone with more know how. Pics of our programmer, wiring center and room stat attached (in that order)!



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Linking as shown 1674569011408.png will mean thermostat does not need to be turned up full, but I would think really need to look at this 1674569193395.png rats nest and work out what goes where, I can see three cables out of bottom of box likely you can work out where they go, in the main we use the colours on the motorised valve cables to work out what does what, as the cable is fitted to the valve by the manufacturer so we can trust the colours, looking at this 1674569594701.png I note the wire on terminal 1, so assume it is Y plan, but I do not see the colours expected on a Y plan three port valve at the wiring centre, so as it stands can't work out what you have.
Thanks for replying.

Assuming by linking the two wires on the stat up that they’ll still be live though, which I guess is not a very safe option, hence trying to do directly at the wiring centre.

If this helps, the wires on the bottom half of the choc block are coming from the 3 port valve. And yes it’s definitely Y plan.
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Not at PC so not easy to work out what goes where. Basic idea is the supply goes to programmer, then from that to both thermostats, and from room stat to motorised valve, and from valve to boiler.

Not got wiring diagram in front of me, but into the motorised valve has two live inputs, one from the wall thermostat that moves valve to centre position, the other from both programmer and tank thermostat which turns off supply to DHW. This moves the valve all the way, note powered to turn off not on.

But colour of wire to valve will help work out the rats nest. White to wall thermostat so likely 4th from left with yellow wire with red sleeve.

So follow that wire and find the red wire on same cable, and link both the termials they feed together.

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