Nest wiring help!

[Yiddo13]

I know there’s a billion threads on nest wiring but I can’t seem to find where I’m going wrong no matter how much I read.

I have Britony combi se boiler the nest was already installed but has never worked properly. I’ve taken everything apart and I have 3 sets of wires.

Black and red from the nest thermostat, I know where these need to go on the heat link.

I also have another set of red and black, coming from the 24v bit of the boiler.

And then there’s 4 cables together from the boiler, blue, brown and 2 purple. I’m guessing these are the ones that call for the heat.

Where on earth do I put these cables in the heat link?

I really appreciate any help.

Edit: should also add the orginal timer which was connected to the boiler has been removed and I don’t have it.

 

[ianmcd]

blue Neutral on nest

Brown Live on Nest


the two purple wires to 2&3 on nest either way round doesnt matter DO NOT make any links as you may have seen on other posts

 

[Yiddo13]

Thanks for the reply. What about the other set of black and red from the boiler?

 

[CBW]

How are you powering the thermostat?

 

[Yiddo13]

I dunno. Thermostat has 2 cables (t1 and t2) which I just put into the t1&2 terminals on the heat link and it has power

 

[Yiddo13]

blue Neutral on nest

Brown Live on Nest


the two purple wires to 2&3 on nest either way round doesnt matter DO NOT make any links as you may have seen on other posts

I have wired it up like this I hear the heat link click when I turn the thermostat up and down but the boiler doesn’t fire up.

 

[ianmcd]

I really hope the black and red wires you have connected to the nest are not the same Black and red wires connected to the boiler

 

[Yiddo13]

No they go to the actual nest thermostat

 

[RandomGrinch]

@ianmcd , would the boiler black and red wires (connector C), need to be linked to allow the purple wires to connect to the stat?
Just as the purples are bridged to enable connector C:

 

[ianmcd]

@ianmcd , would the boiler black and red wires (connector C), need to be linked to allow the purple wires to connect to the stat?
Just as the purples are bridged to enable connector C:

View attachment 288648

No the red and black wires connected to the nest are to power the hive thermostat instead of using the USB connector, where those are connected at the boiler a link needs to be placed in there

 

[RandomGrinch]

No the red and black wires connected to the nest are to power the hive thermostat instead of using the USB connector, where those are connected at the boiler a link needs to be placed in there

I think that is what I meant
I shouldn't have mentioned the red and black - I think that connector c should be bridged to enable the 'stat to work from the purple wires on the multiconnector

Edit: to OP - not something to try without confirmation, we wouldn't want to fry the PCB!