How do you wire up the Honeywell CM907 thermostat?

6 Feb 2013
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United Kingdom
My Honeywell T6360B thermostat is wired with a Blue, Brown & Earth [green & yellow], that is 3 wires for my old Potterton boiler [not a Combi-Boiler].

I want to change the Honeywell T6360B thermostat to the Honeywell CM907 thermostat. The Honeywell CM907 manual shows only 2 wires to fit?

Can the Honeywell CM907 thermostat be fitted with those wires, if yes, How?
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Thank you for your reply. If I understand you correctly.

Terminal A should be connected to the Live wire, which is the Brown wire.

Terminal B should be connected to the Blue Wire.

The Earth [green & yellow] wire should not be connected, but made safe by insulated tape & tucked up inside the backplate.

Please could you confirm, this is right.


I don't know what wires are what on your old thermostat. But A & B on the 907 equate to 1 & 3 on the old Honeywell.

2 should have been a neutral on your old stat. If it went to 3 then it is the switch live back to the valve and should be sleeved accordingly.

The Earth is just that as long as it was connected to the earthing pole i the old stat, and can be left out of the way as the 907 is double insulated.

Remember to leave our old timer on constant for heating an the optimisation part of the 907 is disabled, so you need to go into the installer settings and change parameter 8:eek:P to "1"
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Yes, on my old Honeywell, Terminal 1 was the brown [Live] wire & the Blue wire was on Terminal 3, The earth wire was on the Earth Terminal.

The old timer is the 'PROGRAMMER RWB2' which is near the boiler inside the cupboard. It is on continuous 24 hours setting for the CH & HW.

The boiler has it own thermostat build-in, which has been set between 1 & 2. It can be set to Min, 1, 2, 3, 4, 5 or MAX.

I will change parameter on the new Honeywell CM907, 8:OP to "1" which will Enabled 'Optimisation'.

Thank you for all the info.

Depending on exactly which boiler you have the thermostat there should be on 3 or 4 otherwise it will not perform correctly for hot water.

I would go for4 for now. But post back which obiuler you have.

I am off to bed, I have another day of staring at Powerpoint presentations of shit I already know. :evil:
The previous owners of the flat put the boiler in. All I know, it is a Potterton boiler [not a Combi-Boiler] put in over 20 years ago.

I will put the boiler thermostat on the 4 setting.

Thanks again for all the information.


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