Nest Power Issue

Andy Byford · 2 Aug 2021

Hi all,

I was wondering if anyone could give some advice regarding my nest. It's been installed for around a year and a half and has been working spot on for all this time.

Today I realised the thermostat was not connected to the heat link, upon further investigation it turns out the heat link has no power going to it at all.

The thermostat is wired via a mains plug and stand so is separate power circuit.

The strange thing is, when I plug a USB power cable into the front of the heat link, the lights come on and the thermostat can connect to it (however it does not control the boiler still when you set it to heat). The heat link replaced an old programmer and used the existing wiring.

Does anyone have any ideas what could be causing the issue? Wiring all looks OK and nothing in the house has changes recently. Not sure if there is a fuse located somewhere that could have blown?

Thanks in advance!

CBW · 2 Aug 2021

It’s possible a fuse has blown. What type of system do you have? S pls, y-plan, combi boiler?

Andy Byford · 2 Aug 2021

CBW said:
It’s possible a fuse has blown. What type of system do you have? S pls, y-plan, combi boiler?

I have an S plan system I believe, with 2 port valves.

CBW · 3 Aug 2021

So you havbe a hot water cylinder and tank in the loft? If so, the fused spur connection is likely to be the vicinity of the heat link

Andy Byford · 3 Aug 2021

Slightly different to that as we had a loft conversion so we no longer have a tank, we have a cylinder and 2 shower pumps like this photo.

CBW · 3 Aug 2021

Well, it’ll be powered from somewhere, once found check the fuse, or anything else that might be connected to it.

stem · 3 Aug 2021

Andy Byford said:
The strange thing is, when I plug a USB power cable into the front of the heat link, the lights come on and the thermostat can connect to it (however it does not control the boiler still when you set it to heat). The heat link replaced an old programmer and used the existing wiring.

That's what I would expect. If there isn't a mains power supply to the boiler and Heat link, then when you then supply power to the Heatlink via USB then the lights will come on, however as there still isn't any power to the boiler it won't work.

As Chris says you need to find out where the power to the heating system originates from. Usually there's a fused spur adjacent to the boiler, or the main wiring centre. Something like this:

Untitled

stem
23 May 2012
1

Andy Byford · 4 Aug 2021

Thanks for the reply,

I have had a good look and have had no luck finding a fused spur near the boiler (there is one off a mains socket that powers another nearby socket but that's all) or near the wiring in the tank cupboard centre, or near the heat link. There is one linked to my tank that links to down stairs in the kitchen but that's all live and fine.

The only other place I can think is underneath my kitchen counter behind the cupboards as that is under the heat link, however this has all the cupboard backs on and is inaccessible to check without removing the whole set of cupboards. The boiler used to be in this kitchen area before it was moved to the garage when we got a new one, so if the spur was anywhere I would imagine here.

Any tips to check before removing cupboards to see if it's behind them?

Thanks

CBW · 4 Aug 2021

Andy Byford said:
Any tips to check before removing cupboards to see if it's behind them?

Thanks

Is the boiler working?

Andy Byford · 4 Aug 2021

Yeah boiler is on and is still heating the water fine, it's literally just the heat link that's not working

ianmcd · 4 Aug 2021

Follow the L,N&E fles from the boiler , it should be connected to the fused spur

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 Power Issue

Andy Byford

Attachments

CBW

Andy Byford

CBW

Andy Byford

Attachments

CBW

stem

Untitled

Andy Byford

CBW

Andy Byford

ianmcd

DIYnot Local

Similar threads