Which wires go where please?

tsowayne

Hi, Im wanting to fit my smart thermostat but not sure which wires go where, any help would be appreciated. Photos of existing and new. (i didn't fit the existing)

wateroakley

@tsowayne Hello. For users to help can you post make/model details of the thermostat you are replacing ?

tsowayne

Existing Thermostat is a Danfoss RET2000M

philjohn

If you enter that in the app it should give you a walkthrough of what wires go where.

But as this is a room stat and not a cylinder stat, I'm going to hazard a guess and go L to COM and 2 to NO (Normally Open … e.g. only closes and makes a circuit when there is a demand for heat).

Then park the CPC (earth) and neutral (N) in the P1 and P2 ports.

Edit: also, get some ferrules on those stranded wires to prevent issues down the line with potential for loose connection to cause a fire. You can get a box of ferrules and crimper from most places, including Amazon and Screwfix.

wateroakley

@tsowayne Hello. Please check VERY CAREFULLY what the green/yellow wire on connector 3 is used for on your present thermostat. Green/yellow should always be an EARTH wire. The RET2000M wiring diagram says connector 3 is NC and that will be LIVE when the thermostat is ‘off’’. If in any doubt, consult a qualified professional.

Edit: typo.

tsowayne

Thanks all, the existing wiring does not make sense to me, electrician has been called, nothing is ever straight forward is it.

wateroakley

@tsowayne Hello. Sorry to say, some of the building trades are not safe with electrics. Glad to hear you have engaged a professional.