How to wire a wall thermostat back into the bolier

[diylady]

Hi there

I am moving house and looking to take my honeywell evohome set up with me. I installed the Evohome ( with help from this forum swapping it from a salus receiver to an Evohome BDr receiver) but now want to disconnect it and put the original wall thermostat back . The original wall thermostat is still there and has a choc bloc on it at the moment. Looking at my boiler ( valiant eco tec pro 30 wiring) is it just a simple case of removing the current receiver wiring and putting the the old room thermostat wiring in its place . If so am confised as my wall thermostat only has 2 wires - a live and neutral . I have attached some pictures of the current wiring set up with the wireless receiver and theold wall thermostat wire . Can someone advise on the wiring and what should go where. Thanks in advance diy lady

 

[diylady]

I am moving house and looking to take my honeywell evohome set up with me. I installed the Evohome ( with help from this forum swapping it from a salus receiver to an Evohome BDr receiver) but now want to disconnect it and put the original wall thermostat back . The original wall thermostat is still there and has a choc bloc on it at the moment. Looking at my boiler ( valiant eco tec pro 30 wiring) is it just a simple case of removing the current receiver wiring and putting the the old room thermostat wiring in its place . If so am confised as my wall thermostat only has 2 wires - a live and neutral . I have attached some pictures of the current wiring set up with the wireless receiver and theold wall thermostat wire . Can someone advise on the wiring and what should go where. Thanks in advance diy lady

Read more: https://www.diynot.com/diy/threads/how-to-wire-a-wall-thermostat-back-into-the-bolier.518326/#ixzz5fsQnYSDD

 

[stem]

Don't assume that the wires are actually a 'Live' and a 'Neutral' because they are brown and blue in colour. They may be; but they also may not be. It's what they are connected to at the other end that matters. Where do they go?

 

[diylady]

Hi Stem

Thanks for your message. In answer to your question.
The Grey wire with the brown and blue with ‘old room stat on it’ is the wire that connects to the wall mounted thermostat . I know this because when my heating engineer came round to disconnect it and fit our initial wireless room stat , he disconnected this was the wire for the wall thermostat and and told me he would leave it there wrapped up because if i ever moved house i could take the wireless one with me and reconnect this back up. I have attached a picture of the wall thermostat that this is connected to.

 

[stem]

I would expect that the two wires marked 'old room stat' are connected to terminals A and B inside the Honeywell CM61 as below, but it would be a good idea to check just to make sure.

But first, a couple of notes of caution:

1) If you have had to open up a room sealed compartment to access the boiler wiring terminals (with some boilers you do & some you don't) this should have only been done by a registered gas installer who can then make sure that the compartment is safely sealed up again afterwards. Possibly a Gas Safe installer who recognises your boiler will be able to give you a definitive answer.

2) The existing grey flat thermostat cable is not really suitable for the final connection to the boiler. Suitable flex, akin to what is there now (which is probably also heat resistant) would be better.

Assuming that the above are taken into account, and that the existing wires do go to the thermostat A & B terminals, then:

The white cable marked 'wireless receiver' is removed from the boiler completely, and in its place, the wire that comes from the existing thermostat 'A' terminal goes to the boiler 'L' terminal, and the wire from the existing thermostat 'B' terminal goes to the boiler 'RT' terminal.