DIY Doctor UK DIY Forums

Morning All,
I am about to replace my current Room thermostat with a new Honeywell CM907.
Currently i have the following running into my old thermostat and i am try to work out which wire goes where on the new thermostat

1 NO - Brown wire
2 NC - Black wire with a short brown sheath
3- Blue wire blanked to a lose terminal block. not connected.

which wire is which and how do i connect them up to my new Thermo pls?

Daz

Connect the totally brown wire to "A", the black with the brown sleeve to "B" and the blue remains unused.

plumbob, would the same apply to my problem? I'm replacing a Drayton RTS1 with a Honeywell CM901, the three wires in the Drayton are black to N, red to L, yellow to 3. I believe the black wire is not used but I'm not sure where the red & yellow wires go.

Indeed you are right, the black wire is unused, and as far as I can tell, the connections for the other two will be to the same "A" and "B" contacts. I would suggest connecting the red to "A" although which way round they go is not critical.

Sorry to come back to this issue but I have blue, black and grey wires connecting a combi boiler to my Honeywell T6360B roomstat .
I am now replacing the roomstat with a Honeywell CM907.
I assume the brown goes to A but what are black and grey wires connecting to at the boiler and which one goes to B?

[quote="PrussianBlue"]Sorry to come back to this issue but I have blue, black and grey wires connecting a combi boiler to my Honeywell T6360B roomstat .
I am now replacing the roomstat with a Honeywell CM907.
I assume the brown goes to A but what are black and grey wires connecting to at the boiler and which one goes to B?[/quote]

Are you sure you have those colours?
normal 3 core and earth should be BROWN Black & Grey.
The approved usage is Brown live in to common (Term 1 i think.)
Grey (sleeved blue) as Neutral (term. 2)
Black (sleeved Brown) switch live to Valve (term 3)

Not every one uses same colours but note what colours are in which numbers on original, then find where they go on new one.
Don't know cm907 so can't help,
regards Sparx

Whoops!!! typo.
Indeed they are Brown, Grey and Black + earth

As you wrote- After checking with my meter-Brown is positive and Grey is the neutral. Black has no brown sleeve (but ok,).

I have now connected Brown to A and Black to B and the unit works just fine. It seems that Grey negative is superfluous on the CM907.

Many thanks
(I hope the outside temp sensor is easy to wire in when it arrives)

Hi, i am replacing an old honeywell room stat (3 connections earth, live and neutral, yellow/green, red and black) with a newer Honeywell T6360b room stat. Which wires go to which terminals? I've tried a couple of the obvious configurations but am getting nothing on the boiler. Apart from the old stat not working the heating wqas coming on and off reliably before! I've checked the sues at the main house fusebox too!

Hi all,

any help with this would be much appreciated. I have just bought a CM907 to replace the old turn dial thermostat for my heating. I have a Potterton combi boiler. The instructions with the cm907 looked quite straight forward, just two wires to connect... so I'm not really sure what to do with the 4 wires that are in the back of the old thermostat...

Current wiring into the old thermostat is;

Brown wire - into terminal 1
Grey with blue sleeve - into terminal 2
Black - into terminal 3
yellow and green - assuming this is just an earth?

Which of these wires do a put into A and B on the cm907?

what do i do with the 'spare' wires?

Thanks in advance!