Honeywell CM907

[NotebookNewport]

Replacing a honywell? 4200 3879-001 room stat
someone suggested the above programmable stat.
can someone tell me where the 2 wires from the existing stat go on the new one.
Thanks

 

[stem]

If the two existing wires you refer to are:

1) A live supply,
2) A switched live to control your heating,

You should use terminals A and B. Did you not get installation instructions with the CM907?

If you have an existing programmer or timeswitch, that should be removed, or set to be permanently 'on' otherwise it will interfere with the new programmable thermostat.

 

[NotebookNewport]

Hi and Thanks
I haven't purchased one yet, can leave the timer on permanent too. Just measured across the 2 wires and there is 240vac.
How do I check a switched live to control my heating?

 

[Dan Robinson]

You get warm.

 

[NotebookNewport]

You get warm.

Ha Ha

It won't blow anything then - ok mate - so ok to go ahead then - cheers

 

[NotebookNewport]

Bought one - 2 wires - job done.
Programmed and working superbly!!!
Thanks to everyone.
Cheers