Nest install

[MichaelCo]

Hi everyone

I have just moved in to a new build property and would like to change the thermostats to Nest.

I have 2 (Danfoss) thermostats, one in the hall way and one in the master bedroom.

The boiler is Logic Combi ESP1 35

I think the current Danfoss thermostats are battery powered which might make this more complicated than I hope.

I have attached some images below.

I appreciate any feedback

 

[flameport]

I think the current Danfoss thermostats are battery powered

That changes nothing - they will be going away.

All existing thermostats, programmer, timer or other controls are removed.
The two Nest heatlinks connect to the wiring centre.
Optionally the old wiring to the thermostats could be used to power the Nest thermostats if you want them wall mounted in the same position as the old Danfoss ones.

 

[MichaelCo]

That changes nothing - they will be going away.

All existing thermostats, programmer, timer or other controls are removed.
The two Nest heatlinks connect to the wiring centre.
Optionally the old wiring to the thermostats could be used to power the Nest thermostats if you want them wall mounted in the same position as the old Danfoss ones.

Thanks for the reply.

So the existing black and brown wires could repurposed to the power the Nest if it was wall mounted? Is the loose grey and earth anything to be concerned about?

So I shouldn’t really have any issues?

 

[stem]

You will need two Nest Thermostats and two Heat Links. The two existing thermostat wires [Brown and Black] need to be rerouted to the Heat link terminals 2 & 3 [Heating call for heat, and Heating Common]

Then the Heat link needs 230V to provide it with power connected to N & L. This should be from the same 230V supply to the rest of the heating system, so that the same fused connection unit isolates the entire heating system including the Heat links. From your photo, wiring centre Terminal 13 (Live) and either terminal 9 or 3 (Neutral) would appear to provide this. [Provided conventional installation procedures have been followed and the grey wire to the motorised valve is connected to a permanent live] A quick check with a multimeter would confirm.

If you are going to connect the Nest thermostat to the Heat link to power it (instead of using a remote power supply) then T1 & T2 at the Heat link connect to T1 & T2 at the Nest thermostat. You will also need an earth connection to the earth terminal just to the left of Heat link T1.

Then the process is repeated for the second Heat link and thermostat.

Is the loose grey and earth anything to be concerned about?

That depends what if anything is connected to the other end of it or not. Probably it's not connected at the other end, but best to check.

As an alternative method of installation. If you wanted to install the Heat links where the existing room thermostats are located [Personally I wouldn't want them on show especially if one is in a bedroom as the lights and clicking can disturb light sleepers] you could use the grey wire to connect to a neutral and then link the brown wire (ie the one currently going to the room thermostat) also to the Heat link L to provide the live.