topic Re: NEST THERMOSTAT ONLY WORKING ON MANUAL MODE in Nest Thermostats

NEST THERMOSTAT ONLY WORKING ON MANUAL MODE

Knight2 — Tue, 21 Feb 2023 15:01:02 GMT

Hi all,

Help needed please!

I've recently installed two learning thermostats as I have two zones in my house. The heatlinks work as I'm able to manually turn on the heating but that's all i'm able to do.

The thermostats won't work unless in manual mode - they say they don't have power and will shut down, however will boot back up and work continuously whilst in manual mode but the minute i turn it off from manual, it stop talking the boiler and loses power, then eventually switches off!!

Does anyone have ideas as to what the problem could be?

Thanks in advance

Re: NEST THERMOSTAT ONLY WORKING ON MANUAL MODE

Frustratedddd — Tue, 21 Feb 2023 16:15:45 GMT

A picture of your Heat link connection could help, as this may be a wiring issue.

Are you wired direct from the Heat link to the stat, or powered from a USB on a stand?

Re: NEST THERMOSTAT ONLY WORKING ON MANUAL MODE

Knight2 — Tue, 21 Feb 2023 16:21:15 GMT

Re: NEST THERMOSTAT ONLY WORKING ON MANUAL MODE

Knight2 — Tue, 21 Feb 2023 16:22:33 GMT

Hi, i've just uploaded the pictures of the heat links. we are direct from heatlink to thermostat, We've used the same set up from the previous thermostat that wasn't smart and worked for 7 years

Re: NEST THERMOSTAT ONLY WORKING ON MANUAL MODE

Frustratedddd — Tue, 21 Feb 2023 16:24:27 GMT

Well from what I can see, unless the Grey or black wire is not live, you do not have a feed to the Heating contacts!

Where does the Grey wire go?

Where does the Black wire go?

Re: NEST THERMOSTAT ONLY WORKING ON MANUAL MODE

Frustratedddd — Tue, 21 Feb 2023 16:27:41 GMT

Oh Dear!!!

Your displays are 12v ONLY, IF you have connected the Grey and black to the display, REMOVE NOW!!!

Re: NEST THERMOSTAT ONLY WORKING ON MANUAL MODE

Frustratedddd — Tue, 21 Feb 2023 16:32:11 GMT

Re: NEST THERMOSTAT ONLY WORKING ON MANUAL MODE

Frustratedddd — Tue, 21 Feb 2023 16:34:19 GMT

Can you tell me where the wires go?

The Blue and Brown are obvious, but where do the Black and Grey go?

Re: NEST THERMOSTAT ONLY WORKING ON MANUAL MODE

Knight2 — Tue, 21 Feb 2023 16:47:18 GMT

sure. the grey one is going into '2' and the black one is going into '3'

Re: NEST THERMOSTAT ONLY WORKING ON MANUAL MODE

Knight2 — Tue, 21 Feb 2023 16:48:36 GMT

the grey and black only go into the heatlinks - not the thermostat display

Re: NEST THERMOSTAT ONLY WORKING ON MANUAL MODE

Frustratedddd — Tue, 21 Feb 2023 16:49:02 GMT

I can see that, but where do they go the other end??

Re: NEST THERMOSTAT ONLY WORKING ON MANUAL MODE

Knight2 — Tue, 21 Feb 2023 16:51:05 GMT

into the floor - we have all the wiring from the old thermostats there. They then feed to the boiler. The displays are wired with the following:

Re: NEST THERMOSTAT ONLY WORKING ON MANUAL MODE

Frustratedddd — Tue, 21 Feb 2023 16:53:42 GMT

OK, let's start again!

Where does the Brown come from? - ie: Live Feed?

Where does the Blue come from? - ie: Neutral?

Where does the Grey come from?

Where does the Black come from?

Just remember the display is ONLY 12v, do NOT connect 240v to it. Should you be in doubt at present, turn of now until we get this sorted.

Re: NEST THERMOSTAT ONLY WORKING ON MANUAL MODE

Frustratedddd — Tue, 21 Feb 2023 16:56:42 GMT

Where do those 2 cores go to?

The Brown and Grey at the display end?

Re: NEST THERMOSTAT ONLY WORKING ON MANUAL MODE

Knight2 — Tue, 21 Feb 2023 16:57:13 GMT

bit annoying but i'm not sure - i had it installed by a professional plumber who has fitted nests and hives so i'm confident it was done correctly. i'm currently waiting for a voltage checker so should be able to check the wires this evening! Apologies i'm not much help on the wires

Re: NEST THERMOSTAT ONLY WORKING ON MANUAL MODE

Knight2 — Tue, 21 Feb 2023 16:58:47 GMT

they were going into the base plate as power but it doesn't provide enough power for the unit to work

Re: NEST THERMOSTAT ONLY WORKING ON MANUAL MODE

Frustratedddd — Tue, 21 Feb 2023 17:01:31 GMT

Put it this way, normally you would have a link from Live to term 2, but I do NOT want to suggest anything until you know the wiring. I need to know the connections 2&3 where they go.

Just make sure you do NOT get 240v to the display as that's expensive!!

Re: NEST THERMOSTAT ONLY WORKING ON MANUAL MODE

Knight2 — Tue, 21 Feb 2023 17:03:51 GMT

ok fair point - i will look into the wires and come back to this thread - it's defo not 240v as when they were connected to the base plate, the technical information showed that the power was 3.4v (google told me that it needs to be 3.8v minimum)

Re: NEST THERMOSTAT ONLY WORKING ON MANUAL MODE

Frustratedddd — Tue, 21 Feb 2023 17:07:28 GMT

Why is the Heat Link on the floor if connected by the plumber?

Re: NEST THERMOSTAT ONLY WORKING ON MANUAL MODE

Knight2 — Tue, 21 Feb 2023 17:34:42 GMT

I asked for it not to be connected onto the wall until i know the units work.. As the issues were happening straightaway