Nest heatlink wiring to replace Honeywell

Barney123m · 13 Feb 2016

Can anyone help me with the wiring - replacing my Honeywell T45 with the Heatlink for a Nest 3rd gen? Does the common need a jumper from the live? Many thanks for any help, see attached pics

muggles · 13 Feb 2016

If you do a search on here, you'll find that this has been asked and answered many times recently...

Honeywell-Nest
N-N
L-L, 2 & 5
4-3
3-6
If connected, 1-4

Barney123m · 13 Feb 2016

Thanks Muggles, I have connected exactly as you said and everything setup (wifi, connected, account etc) but boiler not firing up and won't work on manual either. If I put Honeywell back works again.

I do have a cable 1 into Honeywell but nothing on 2 – is that right? Any thoughts?

muggles · 13 Feb 2016

Can you post a photo of your Heat Link wiring? You won't normally need anything connected to the old HW Terminal 1, unless you've got an odd system! Did you have a room thermostat before, or just the timer?

Barney123m · 13 Feb 2016

Thanks really appreciate this ... posted a pic of Honeywell too.

muggles · 13 Feb 2016

It's hard to see what you've done there. Maybe post a picture taken from the front, rather than at an angle from the side where it's really difficult to see what wires go where? A bit more illumination wouldn't go amiss either...

Did you have a room thermostat before, or just the programmer?

Barney123m · 13 Feb 2016

OK this better ... and yes 1 room stat, not done anything with that yet, but tried with it turned up and down. Was going to remove once nest working properly

Echo the husky · 13 Feb 2016

Come on man use the rear entry holes on the nest, don't ram the unsheathed wires in the surface wiring entries! You had lovely neat wiring before.

Edit: I looked on google images to show you a photo of a properly wired one but could not find one that met UK wiring standards!

Barney123m · 13 Feb 2016

I was going to tidy it all up once working – second time I have wired it all up. Any idea why boiler won't fire up?

Echo the husky · 13 Feb 2016

Good. The wiring all appears to be in the connect terminals. I take it you have a 3 port valve?

If you have a multimeter, set it to AC volts, black lead to neutral terminal on Heatlink for all tests, then check:
With heating and hot water off there should be 240V on terminals L,1,2,4,5
With only heating on there should be 240V on L,2,3,4,5
With only hot water on (and cylinder stat calling) there should be 240V on L,1,2,5,6

muggles · 13 Feb 2016

Barney123m said:
OK this better ... and yes 1 room stat, not done anything with that yet, but tried with it turned up and down. Was going to remove once nest working properly

You'll need to turn that up to make your heating work with Nest attached. Eventually, you can re-use those wires to power your Nest, although to do that you'll need to wire your Heat Link into your heating's wiring centre rather than where the old programmer was

As far as I can see you've wired everything correctly, save for not having connected the Earth, so it suggests that your links between L, 2 & 5 perhaps aren't linking properly. Time to get the multimeter out...

Barney123m · 13 Feb 2016

Thanks very much to both of you for help, will get multimeter out tomorrow but quick test looks like not getting 240V at live.

diynot

If you need to find a tradesperson to get your job done, please try our local search below, or if you are doing it yourself you can find suppliers local to you.

Select the supplier or trade you require, enter your location to begin your search.

Are you a trade or supplier? You can create your listing free at DIYnot Local

Nest heatlink wiring to replace Honeywell

Barney123m

muggles

Barney123m

muggles

Barney123m

Attachments

muggles

Barney123m

Attachments

Echo the husky

Barney123m

Echo the husky

muggles

Barney123m

DIYnot Local

Similar threads