Installing Honeywell CM921 RF

[tripty]

Hi, I'm installing a new wireless Honeywell CM921 thermostat. Its replacing a 20 year old mechanical thermostat, I'm putting the receiver where the mechanical thermostat is/was.

Now, I believe I have to link the live to terminal A in the receiver, I'm following the direct control diagram on the MIs, but what type of wire do I have to use for the link?

 

[stem]

If your heating requires a 230v live to make it run, you are correct in that you link the live to 'A' (Some newer boilers have a separate two wire connection that needs a potential free contact, in which case you wouldn't link it)

Usually installers use a small cut off piece of the cable they are wiring the thermostat with, however as your wiring is already there you need to find something similar. Your heating system should be fitted with a 3A fuse, so anything in brown suitable of carring 3A will be fine (0.75 to 1.0mm). It would be best if it was of similar diameter to the cable already in the 'L' terminal. Because this will contain two wires, the grip can be better if they are the same diameter.

 

[tripty]

Cheers stem, I used a little bit of the live from a 1.0mm twin & earth cable and its working perfectly so far.