[Closed] O/T Installing a Nest Thermostat

The wiring is no different to any other thermostat, it's just a relay connection to power the boiler. The main PITA with moving a thermostat is running the mains cable to the new location.

I'll go with a Nest stand so no worries about mains to the thermostat.

Its wiring the heat link into the boiler that I am concerned about - connecting the Heat Link to the boilers control circuit.... The boiler is a Worcester 12/14 Oil combi boiler -

They are pretty much all the same, it's just a Live wire which when powered, powers up the boiler. Very hard to do any damage by miss wiring it, if you connect it to N or E the boiler won't fire and the RCD will probably trip - so I wouldn't worry about it.

Basically the thermostat is just a fancy single pole switch, no different to a light switch.

Having just been out to look at the boiler - I can see where the thermostat wire comes out of the house and in to the garage - this wire goes into the front of the boiler next to the control panel.

I cant find a control box with any wiring at all though? With the lid off there are no wires/circuit for 'call for heat' & common etc? Maybe I am looking in the wrong place....

More likely I'm thick as a whale omelet but I cant seem to understand where I would wire in the heat link wireless unit?

Footflaps - are we at cross purposes? I know that wiring the actual nest thermostat is just two wires, that bit is easy to wire up.

BUT.... its the wireless heat link that communicates with the Nest Thermostat that I need help wiring up. I cannot see a junction box in or next to the boiler nor enough wires to connect up the 'call for heat' and 'common' wires. Again might just be me, thanks for your advice so far!

My 'Heat Link' went in next to the hot water tank, the Nest thermostat (now also the hot water control) went in the same place as the old thermostat, the old heating control panel is now not in use at all (but still there, otherwise its a hole in the tiles).

Combi so no hot water tank and no obvious wires... hence my issue really. There must be a junction box somewhere with wires....?

what boiler is it?

thwapy

If your existing thermostat is a simple dumb unit with no permanent mains going to it then you'll need to connect the twin core cable from the boiler to the common / call for heat terminals on the heat link. You'll also need to provide the heat link with a mains power feed, taken from i'd suggest the fused spur or whatever that powers your boiler.
I have the wireless part of the next plugged into USB adaptor on a stand but as you've probably seen you can hard wire it to the 12v output from the heatlink.

I’ve just had a WB combi installed. They installed the Heatlink at the same time and my sparky is today wall-mounting the Nest thermostat using some Cat5.

I can’t help with the specifics of installing the Heatlink itself save to say that the 28(?) page installation manual goes through it in quite some detail. Google is your friend.

Worcester Heatslave 12/14.

I have found all the wiring under a panel on the boiler.

The thermostat had a live and neutral running to it but I think I need to wire the heat link into the wires on the control panel?

thwapy, I think you have it backwards. The wireless box will connect to the boiler using the wires which currently go to the old thermostat.

The new Nest thermostat talks to the wireless box wirelessly, that's the point! You can run a power lead between them if you want to but this isn't necessary.

Can it really be that easy? The thermostat on the wall has live and neutral going to it? Do I just need to connect the nest heatlink to that?

yes. 🙂

The Nest thermostat doesn't need to be hard-wired to the boiler or to the Heat Link box. You can put it anywhere you can plug the USB cable in!

Heatlink in garage next to boiler, thermostat in living room and they are connected wirelessly. Fitted mine myself I did run power wire behind plaster board and comes out just above double socket with usb sockets

The thermostat in our dining room just has power to it? Brown live and Blue Neutral wires but nothing to control 'call for heat' and 'common'. Therefore I must have to wire the heat link into my boiler? I have power but no other controls to call for heat?

Bruneep - guessing you had more than two wires into your heatlink?

Those brown and blue wires are the 'call for heat' and 'common'. They do have power but think of it like a light switch. As a test, join the two wires together, your boiler will come on. Separate them and it will go off again.

The HeatLink also needs main power, I'll go and take a photo....

Yes please to photos! Give me a bike to strip and put back together any day!

So those two wires are call for heat and common. I just need to take some cable and wire it from the mains on the boiler to the live and natural on the heatlink.

Sorry, I had forgotten we had a new boiler fitted since I fitted the Nest. Looks like the plumber has completely rewired it in a different way so a photo of my setup doesn't really help you.

In mine the power goes to the HeatLink first, then goes on to the boiler supply. The mains live is also jumped to the common input and just a single wire runs from the 'call to heat' to the boiler. It does the same thing, but without being able to take a picture of the boiler end it doesn't help to explain it very well!

But yes, sounds like you have it now, there are multiple ways you can do this.

This is mine ...

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The nest heat link box is powered from the same power in for the boiler, the signal back to the boiler goes to the normal timer switch connector and the switch on the boiler itself is just permanently left off ... The thermostat I have on a stand in the living and run it all off the app on my phone.

This is on a combi without a hot water tank (gen 1 nest) if you want to run both or a duel circuit heating system you need a gen 2 and multiple heat links I believe.