Nest 3rd Gen Thermostat into Y Plan

[Chetz01]

Hello, this forum has been helpful before so I thought I would ask something new!

I have recently purchased a Nest 3rd Gen Thermostat and I'm looking to install it myself, the system seems to comprise of 2 parts, a Heat Link and a digital Thermostat.

My house has a regular boiler fitted with a Honeywell ST699 programmer next to it which you can select hot water or heating (or both). My airing cupboard upstairs has the usual hot water tank, 3 port Honeywell valve and a wiring junction box. The hallway downstairs has a dial type Honeywell thermostat which when I opened up had a total of 4 wires including earth. The house itself is about 15 years old.

So my question is how would i wire the the thermostat in the Hallway with some power, as currently I believe its supplied with mains voltage and the Nest requires 12v? Would i need to rearrange things in the junction box? I know the Nest heat link can provide power to the Thermostat if you connect the T1 and T2 cables but I having difficultly understanding/tracing the wiring. Any help or advice appreciated.

 

[muggles]

You need to rearrange things in the junction box (wiring centre) and use two of the four cores in the thermostat to power the Nest, by connecting the other ends of those cores to T1/T2 in the Heat Link. Unless you have a multimeter and know how to use it, this isn't really a DIY project

 

[Aquaheat]

Hello, this forum has been helpful before so I thought I would ask something new!

This really isn't something new. Use the search function and put on nest!

Nest isn't a DIY job unless you can read the quite simple wiring diagrams. If you need step by step guidance just call in a Pro.

The majority of boilers need to be opened up and will probably need an RGI to do this.

We don't tend to give out advice on these as there is a high chance of you getting something wrong and harming yourself, others or your nice new expensive nest.

Call in a pro to do it and save us all the hassle.

Jon