Call-for-heat on Boiler circuit

[Kaysar Alim]

Hi All,

Just look for a quick solution so I can complete my installation of the nest thermostat in particular the heat link.

from the image attached I'm seeking your help to understand which terminal:juggle: I should attach the call-for-heat from the heat link box for the SPDT relay.

Your help would be much appreciated.

Many thanks,
Kaysar

 

[davesparks]

What is that a picture of? And what do you mean when you say heat link box?

 

[telectrix]

what's the marking on 3 & 4. can't read on pic.

 

[davesparks]

At a guess that's the connection box of a boiler and 3&4 are L and S/L

 

[ruston]

I would go with that , looks just like stat link.

 

[Megavolt]

Hi All,

Just look for a quick solution so I can complete my installation of the nest thermostat in particular the heat link.

from the image attached I'm seeking your help to understand which terminal:juggle: I should attach the call-for-heat from the heat link box for the SPDT relay.

Your help would be much appreciated.

Many thanks,
Kaysar

Looks to be a Vaillant boiler. From memory left side low voltage right side 230v.

Remove red link and put nest switching across there.

 

[Megavolt]

The bus connection will most likely need to be removed as that will proberly be from a existing control

 

[Leesparkykent]

Looks like a vaillant Boiler.