Replacing Honeywell reciever with Nest Heat Link: wiring que

10 Jan 2015
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United Kingdom
My first attempt at wiring...I'm a bit at a loss with it though! Any help is my existing Homeywell BDR91 receiver which I need to replace with Nest Heat Link:


Here is a picture of the Nest Heat Link manual:


I'm troubled by the fact I have 2 wires going into each of the Honeywell N and L I just take them and put them in the N L slots of the Nest?

Secondly I'm unsure of where the A and B go into the Nest Heat Link...looking at another post it seems A>2 and B>3 but I'm really unsure...please help!

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ehilst delivering the basics,the Honeywell didn't seem very agile. Because we live in a large studio space, we found ourselves going to the thermostat frequently to adjust. Nest felt like the promise of it learning would help. As well as the remote app when we have to leave all of a sudden for work. Geofencing feature also was a bonus. All in all its a tight promising package. We shall see...
Thanks for that prompt response - I also have the 'Honeywell package' and have not really grown to love it. Installation now about 12 months old.

I have issues with its 'intelligence', ie it seems to turn the boiler off too early before reaching target (well before).

The room was 18 when we got in yesterday, I manually upped the target to 20, and an hour later it was still only at 19.

My installers appear to be not particularly au fait with its operation either.

Thanks again for the reply and best of luck with the new chappy !!


I have the Honeywell wireless thermostat with this receiver. Please see image below of the wires going into the Honeywell receiver.

Can anyone confirm where I connect the cables on the Honeywell into the Nest Heat Link?

I can see that I only have a connection at terminals A and B - where do I connect these cables on the Nest?

I guess the blue and brown, live and Neutrals go to the same terminals on the Nest Heat link, but do I need to provide a second live link?

If I then want to hardwire the Nest Thermostat into the Heat Link how do I do it? I see they supply a USB cable, but is there a cable supplied to connect it directly and if not, what cable do I need?

Many thanks! :)
Edit - just to confirm after re-reading the above:

The terminal marked A on the Honeywell that has the yellow wire goes to 2 on the Nest Heat Link

The Terminal marked B on the Honeywell with the black cable in my setup goes to 3 on the nest.

Then just wire L and N in the same way as I have on the honeywell, naturally blue to Neutral and Brown to Live.

Does it matter that I don't have anything connected to the second live terminal or do I need to bridge it?

My boiler is Boiler 30CDi

Previous stat Honeywell BDR91

Current wiring

Terminal A Black wire

Terminal B grey wire

When the old thermostat is power up there is 12 volts across A & B.

The instructions say insert A & B into terminals 2 & 3 on the Nest.

Terminals 2 & 3 are marked as being 24-230 50-60 hrz

Is this correct ?

Is there a chance of blowing the circuit board on the boiler.

Thanks for reading
I’m having a similar problem to the original post.
What wire currently in my BDR91 should go into 2 on the Nest HomeLink?
Here’s a photo of my BDR91.


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