Nest Heatlink wiring to combi boiler.

[Zmaster2k]

Hi all,

Wiring up a Nest Gen3 Thermostat tomorrow on my combi boiler an ancient Worcester 24i RSF. That currently dossnt have a stat but an old mechanical clock.

It does have the option for a stat, so. I've opted for a neat Gen3 off my sister who bought one but didn't work in her new house.


Below is a wiring diagram from my manual.
Currently wired up like the diagram on the right.




So ill be wiring it up like the left.....


However what terminals do I wire them to on my heat link?

Thanks in advance
Matt

[Zmaster2k]

Forgot to upload the nest diagram.

[Pheo]

I’m thinking N,L and 3 on the nest diagram based on what I can see of the other one.

[Zmaster2k]

Zoomed in a bit..... But pretty much My thoughts....

[Zmaster2k]

[Zmaster2k]

Anybody? 💭

Don't want to fry the heatlink 😂

[thebraketester]

So.... Switched Live (grey).... Live(brown).... Neutral(Black)



Black goes in N.... Brown goes in L.... Link L-2 with a jumper wire..... Grey goes in 3

[SS9]

It's been ages since I installed mine (did it with a plumber mate) - If I recall correctly, I had a live and neutral coming from the boiler into the heatlink, then we linked the live from the live terminal on the heat link into another terminal on the heatlink and then another terminal on the heatlink back into the 'call for heat' terminal on the boiler.

The reasoning was something to do with the heatlink closing a loop when calling heat which then sent 230v back into the boiler to trigger heat if that makes sense.

I'm not a sparky so don't quote me on this but figured it might help.

[SS9]

thebraketester said:

stuff...

Beat me to it - but thankfully aligns with what I said!

[Zmaster2k]

So on my wiring....


RN = Neutral
RI = Switched Live
RL = call for heat

There's a link already In place on boiler, that needs swapping over.

[thebraketester]

Zmaster2k said:

So on my wiring....


RN = Neutral
RI = Switched Live
RL = call for heat

There's a link already In place on boiler, that needs swapping over.

No

i Think you need to wire yours up as per the CN, CI and CL come to think of it

Remember, the nest link box isn’t a thermostat, it’s a switch.

Edited by thebraketester on Tuesday 11th September 07:55

Edited by thebraketester on Tuesday 11th September 07:56

[Zmaster2k]

Yeah that makes sense, like replacing the mechanical timer and switch completely.

[FRG0]

RN to N on Nest
RL to L and link to 2 on Nest
RI to 3 on Nest

The time clock can be left in and just overridden as the stat will be the ultimate 'call for heat' as in if the clock was calling for a boiler run but the link wasn't in place (RL to RI) as in your photograph the boiler wouldn't fire.

It can be done with some 3 core flex as the Heat Link doesn't require an earth, just sleeve the green/yellow with brown if you have any.

[Zmaster2k]

thebraketester said:

So.... Switched Live (grey).... Live(brown).... Neutral(Black)



Black goes in N.... Brown goes in L.... Link L-2 with a jumper wire..... Grey goes in 3

Hero this sorted it....

All working as it should.

Even linked to my Google home seamlessly 😂


Thank you all for the help.

[Zmaster2k]

FRG0 said:

RN to N on Nest
RL to L and link to 2 on Nest
RI to 3 on Nest

The time clock can be left in and just overridden as the stat will be the ultimate 'call for heat' as in if the clock was calling for a boiler run but the link wasn't in place (RL to RI) as in your photograph the boiler wouldn't fire.

It can be done with some 3 core flex as the Heat Link doesn't require an earth, just sleeve the green/yellow with brown if you have any.

Wired it up to the mechanical clock terminals instead.... Works like it should.

Should I switch to the RL instead?

[FRG0]

Zmaster2k said:

Wired it up to the mechanical clock terminals instead.... Works like it should.

Should I switch to the RL instead?

No, it's fine where it is.

[thebraketester]

You are welcome. When I installed mine earlier this year I had a similar amount of head scratching with similar levels of information void.