Drayton thermostat replacing with Nest

[zafiq]

Can anyone help please
I'm willing to install nest thermostat and nest heat link I've got two zoned centre heating upper floor and ground floor control by two separate Drayton thermostats my question is where can I install Nest heat link? The place where existing Drayton thermostats are? Or by the system boiler where the Drayton heating programmer is?
Can anyone guide

 

[stem]

Unfortunately, there is no standard way to wire up a heating system. The Nest will come with instructions and based on what you have told us we can't give any additional advice to what they contain.

The wiring you have will depend upon the make / model of components originally used (thermostat / programmer / boiler / wiring centre) their physical location in relation to each other and the personal preferences of the installer. So we would need much more information than you have given. If you can post details of the make and model of the existing components, and a photograph of the wiring at the programmer and wiring centre someone may be able to assist.

Also, which model of the Nest do you have? By this I mean do you have the Nest with dual channel heating control for a two zone system, and does it include hot water control. i.e. do you have a combi boiler, or stored hot water system that will also be part of the Nest control?

 

[zafiq]

Thank you Stem for reply I'm posting some images I have 2 Drayton thermostats exactly same one upstairs/downstairs then I have Drayton programmer for megaflo and centre heating then I have Vaillant Ecotec Plus 637 system boiler
The plan is to replace existing Drayton thermostats with Nest heat link and nest thermostat I've bought two sets of nest for two zone controlled heating

 

[zafiq]

Thank you Stem I'm willing to install this model of Nest instead of Drayton thermostat

 

[stem]

OK, so you have two Nest thermostats, do you also have two Heat links, or just the one?

 

[zafiq]

Yes two heat links

 

[stem]

OK,

The Wiring to your Thermostat now is:
Black = N (Neutral)
Brown = L (Live)
Grey = 3 (Call for Heat)

So at the Heatlink
The black wire should go to N (Neutral)
The brown wire should go to L (Live)
The grey wire should go to 3 (Call for Heat)

You will then need to add a link between terminals L and 2 (common)

The photo of the Heatlink you have posted is also one that also has control functions for the hot water system (terminals 4, 5 &6) which you won't be able to use. You will also need to set any existing programmer for the central heating to be permanently 'on' (or reconfigure the wiring at the programmer) otherwise it will override the Nest.

T1 and T2 can be used to provide power to the Nest thermostat, unless you are using a separate plug in power supply.

You could install the Heatlinks at the wiring centre, remove the existing programmer, and also have hot water control via the Nest, but it will be much more complicated. There is a model of Nest with two Thermostats and one Heatlink suitable for twin zones which would have been better if you did want to go that route.

 

[zafiq]

Thank you Stem that is what exactly I was planning to do cause I'm no bothered on out hot water I only wanted to control centre heating through Nest
Many thanks
Kind regards