Honeywell T40

[stempjks]

Currently have a Honeywell T40 Thermostate would it be possible to install a CM907 easily. Currently have four wires coming out of the wall as follows
Blue to terminal 2
Yellow to terminal 3
Red to terminal 1
earth to earth
how would these go into a Honeywell CM907 is it possible ?
Thanks

 

[gas4you]

If its wired to normal standards, Blue = neutral, Red = live from boiler/wiring centre, yellow switched live back to boiler/wiring centre.

MI's with the CM907 will tell you which terminals to use.

If its an RF unit (don't fit Honeywells myself) all you will need are the red and yellow to the sender unit.

 

[stempjks]

Many thanks gas4u.

 

[simond]

Terminals you need are A and B. As Dave says, normally you'd expect the cables to be red and yellow. It is polarity insensitive.

The blue (neutral) needs to be safely insulated off, or in a 907 there are two spare 'parking' terminals.

 

[stempjks]

That's a big help - thanks Simon