Nest heat link

[Winnie69]

Hi all! Im about to install a Nest 3rd Gen thermostat and was hoping members could offer some advice before I start.

I have a Y plan CH system; boiler in the garage, timer and fused spur in the kitchen, CH thermostat in the hallway, and pump, wiring centre, and 3-way valve in the upstairs airing cupboard.
I intend to install the heat link inside the airing cupboard adjacent to the wiring centre. I have some 3 core 1mm2 flex that I would like to use. I would use one lenght for L, N, & E, one length for the 12V supply to the thermostat/ display, and one length to connect to the HW thermostat and 3-way valve for which I will use all three cores, including the earth. I expect the cable lenght to be about 30cm. Is it acceptable to use the green/yellow cable in this manner, and is 1mm2 cable OK?
Also, as I will not have a permanent supply from the fused spur to the wiring centre, can I use one of the now defunct cables from he old timer to the wiring centre? I've had a look behind the timer and see that I can easily connect to the 230V supply to the timer.

Any advice would be greatly appreciated.

Thanks.

 

[littlespark]

You can’t use the green/yellow cable for anything other than a cpc.

You can buy metre lengths of 4 core or 5 core flex from most wholesalers or diy stores.

 

[James]

install the app on your phone, it has some great Q and A type tutorials for connecting it all up.

be very careful here, there are many pitfalls for you.
the wiring center will be a jumble of cables that may be difficult for you to identify.
there will be enough spare cores from timer unit to wiring center normally for you to use some spares as a permanent supply.

I have been to a few diy installs like this where the customer has inadvertently fed 230v into a boilers control board in the wrong terminal and cost themselves a lot of money.

be absolutely sure you know what you intend to do and how you intend to do it before starting to work on it.

drawing it out on a sheet of paper will help you to understand what goes where.

 

[Winnie69]

You can’t use the green/yellow cable for anything other than a cpc.

You can buy metre lengths of 4 core or 5 core flex from most wholesalers or diy stores.

Thanks Littlespark, is what I suspected. I'll look harder for some 5 core cable by the metre. Is 1mm2 cable ok for this?