Replace a Honeywel CM907 with a Nest Thermostat v3

[Stuw101]

The best looks hideous though and can’t find much on trv’s from them. After much research today online and via companies Tado apparently will work as well but they won’t tell you how to wire it until you buy a kit then they send you the instructions on how to do it. They have assured me I only need the three wires I have though to make theirs work. They also said I wouldn’t need the extension kit either. Will have to send the Drayton back and will give them a try. Looks a bit nicer than the best e.

 

[stem]

Tado make a basic 'smart thermostat' that is battery powered and simply replaces an existing thermostat using just two wires. in your case 'live' and 'switched live'.

Anything else requires an extension kit which is mains operated using a minimum of 3 wires (In cases where 'live' and 'com' can be the same connection, for boilers with 230V controls) or 4 wires as shown below (for boilers with 24V controls).

 

[Stuw101]

Hi thanks so can you set the different tempratures in rooms independently with the app from your phone and control the additional trv tempratures without the extension kit? I thought that was just for water control? I have a logic 35 boiler. I have ordered the harness to make it open therm compatible and would like a smart thermostat and kit that will allow me to Utilise that as well function as well. Does the bridge not sort the rest out when plugged to a router? Their customer service didn’t mention any of this.

 

[stem]

Hi thanks so can you set the different temperatures in rooms independently with the app from your phone and control the additional trv temperatures without the extension kit?.

I have installed a couple of Tado thermostats, but not with their Smart TRV's, so not 100% sure. However, as I understand it their Smart TRV's don't actually control the boiler, so they don't need to a physical electrical connection. The app simply sets the TRV position, just as you would by turning the head on a standard manual TRV. This position setting is communicated to them wirelessly via the internet bridge.

The extension kit has two purposes. One, it allows the smart thermostat to be mounted remotely and used as a wireless thermostat, and two as you rightly say for systems that require separate hot water control.

Never used OpenTherm with Tado, so don't know about that bit.