Wiring Nest Heat Link To Combi Boiler

NathanMorgan

im trying to connect a Nest thermostat which requires a Heat Link to be installed for the Nest to switch the heating on/off wirelessly.

I've gone as far as removing the existing wired thermostat and I've had power to the Heat Link but can't figure out the Call-for-heat wiring goes.

I have an earth and black wire remaining but can't figure out where they need to be connected for the Heat Link to work.

Any help would be much appreciated.

Rubidium

You have not provided enough info.

Nobody knows what boiler you have and what stat you are effectively replacing with your Nest/Heat link.

On the Heat Link:

2 = Common
3 = Call for heat

NathanMorgan

it's a Grant Vortex Combi 21e Boiler and im replacing a Honeywell wired thermostat.

Rubidium

The roomstat on your Grant Vortex is connected to terminals 25 & 26 on the circuit board.

25 = ON - Call for heat
26 = Common

So it's easy to connect up to the Heat link unit, which I assume has a volt free relay.

NathanMorgan

do I just need to put the old wiring of the thermostat into terminals 25 & 26 and the Heat Link will work or will I need to do something else?

Rubidium

NathanMorgan wrote: »

do I just need to put the old wiring of the thermostat into terminals 25 & 26 and the Heat Link will work or will I need to do something else?

I thought that you had a clue!

The old stat wiring should have already been connected to terminals 25 & 26 of the boiler circuit board.

You are now connecting the Heat link unit to the boiler in place of the room stat.

If you don't follow what I have posted, then you need to get it installed by somebody who does!

NathanMorgan

im replacing the wired stat and using the Nest wirelessly in a different location to where the old stat was so im not using T1 & T2 on the Heat Link so I need to figure out how to get the boiler going when it comes to turning the heat up on the Nest wirelessly.

Rubidium

NathanMorgan wrote: »

im replacing the wired stat and using the Nest wirelessly in a different location to where the old stat was so im not using T1 & T2 on the Heat Link so I need to figure out how to get the boiler going when it comes to turning the heat up on the Nest wirelessly.

You seem to be way out of your depth. T1 & T2 on the Heat link are the 12V supply to the Nest stat and irrelevant to connecting the Heat link to your boiler which is very easy - just two wires.

NathanMorgan

the wires I've got is Live which is in Live in the Mains terminal on the boiler board and Live in the Heat Link.

Neutral in the Mains terminal in the boiler board and Neutral in the Heat Link terminal.

Im left with the black and earth cables and need to know where to put these in the boiler board and heat link.

Alias_Omega

I needed a 5 core flex from the boiler to the heat link. Then put the thermostat cable into the heatlink.

The 5 core was used for -

240v supply
240v neutral
earth - not used in heatlink
boiler call
boiler return

Then, extend out the thermostat cable into the heatlink.... hey presto..

Rubidium

NathanMorgan wrote: »

the wires I've got is Live which is in Live in the Mains terminal on the boiler board and Live in the Heat Link.

Neutral in the Mains terminal in the boiler board and Neutral in the Heat Link terminal.

Im left with the black and earth cables and need to know where to put these in the boiler board and heat link.

You have been told but you obviously do not understand.

It really is very simply!