Nest query again!!

[NGreen18wood]

I have installed the nest replacing Grasslin control box and Honeywell thermostat. I can only get hot water and heating when the nest thermostat isn't connected. Any suggests??

 

[stem]

First of all, you shouldn't still have a room thermostat wired in when the Nest is also trying to carry out the same function. Take the wire out of terminal 3 of your Existing room thermostat and put it in terminal 1 with the wire that is already there. What happens now?

Edit

Having read your post again, it now appears that you may have removed the thermostat, but have still posted photos of it. Are the photos of the system before you installed the Nest?

If so, you have sent us photos of a working system, So how can we troubleshoot? We need to know what the situation is now after you have wired the Nest in and the fault appeared.

 

[NGreen18wood]

Sorry been a frustrating day. This is what I have done so far. I know the wiring needs tidying up

Remove wires from timer .
Live goes to live neutral goes to neutral
From live link to 2 and 5
Then from old timer put 4 of old timer into 3 of nest =ch on.
Then 3 of old timer into 6 of nest =Dhw on
Then 1 of old timer to 4 of nest = Dhw off.
Remove wired room stat and connect common and sl together = 1 &3 .
Then you can have the nest as a wireless set up only

Read more: //www.diynot.com/diy/threads/i-need-some-advice-on-installing-a-3rd-generation-nest.474488/#ixzz4Xq48c72p

 

[Gaz the Sparky]

You need to remove the wired thermostat wiring from the wiring centre this then gets connected into the nest home link to give the nest stat 12v from the home link

you then remove the 230v thermostat and connect the nest stat to the cabling

do not connect the stat first but install the cabling to the homelink first otherwise you will blow the stat to pieces

if you are struggling you should call a electrician in or you can search the nest pro website for a registered installer.

If you are local to me then i am a Registered installer

 

[NGreen18wood]

Thank you I am using the nest thermostat wireless

 

[Gaz the Sparky]

Glad you got the stat working

 

[NGreen18wood]

Not sorted yet. The boiler doesn't come on when the thermostat is connected

 

[stem]

Live goes to live neutral goes to neutral

Correct.

From live link to 2 and 5

Also correct. This provides a live supply to the Heating and Hot Water Common terminals.

Then from old timer put 4 of old timer into 3 of nest =ch on.

Grasslin 4, 'Central Heating On' = Nest 3 'Heating call for heat' That's as it should be.

Then 3 of old timer into 6 of nest =Dhw on

Grasslin 3, 'Hot Water On' = Nest 6 'Hot Water call for heat' That's too is as it should be.

Then 1 of old timer to 4 of nest = Dhw off.

Grasslin 1, 'Hot Water Off' = Nest 4 'Hot Water Satisfied' also correct.

Remove wired room stat and connect common and sl together = 1 &3 .

OK fine, that should do the trick

All looks as it should be. Unfortunately I can't follow the wiring center wires in the photograph, but if nothing has been disturbed in there and it worked before, then it should be OK.

So I can only suggest that you check the connections to make sure that they are good and secure and that the screws are clamped on the metal conductors and not just the insulation.

As you have not hard wired it, I assume you are getting 12v to the Nest Thermostat with a plug in power supply and that it is powering up OK.

 

[NGreen18wood]

Thank you all for your help. I checked the wiring in the wiring centre and put it back to how it was. Working fine now
Thanks again everybody for your help