Replace Old Honeywell Dial Room Thermostat

[Philayl]

Hi, I am wanting to replace my old Dial thermostat with a Computherm Q3RF unit, but am a bit unsure of the rewiring from the old one to the new one, the new receiver unit is going in the same place as the old stat. On the Honeywell the connections go in number order 1-4-3-2-5, a red wire is connected to No1, a yellow wire is connected to No3, and both the blue and black are connected to No2

as can be seen, the blue wire goes to the controller which is a Drayton Tempus Four, the boiler is an 16 year old Ideal Classic.


the new receiver unit has five terminals marked N-L-1-2-3, above terminal 1 is NO, terminal 2 shows COM, and terminal 3 is NC. Any help would be gratefully received.

 

[Dan Robinson]

You put the receiver by the wiring centre.

On you old thermostat -

red = switch from clock
yellow = switch back to heating
blue is neutral
black is unnecessary, btu being used as an extra neutral.

The equivalent in the receiver is

2
1
N respectively.

You need to sort out the L yourself.

Safely.

 

[Philayl]

Thanks Dan, so none of the existing wires are live? Phil

 

[Dan Robinson]

The red and the yellow are, but only switched. Not permanent.

 

[Philayl]

Thank you for that Dan, I will set up a permanent live from somewhere, the only thing I don't understand is there appears to be only a red and blue going to and from the Drayton controller, I would have thought that the controller needed a permanent live going to it, or will that be a separate feed that is behind the controller, if so can I tap into that, fortunately the back of both units go direct into the airing cupboard where all the wiring for the heating and hot water is so I can easily pick up a live there? Phil

 

[Philayl]

Thank you Dan, all fitted and working, your help was invaluable. Phil