How do you wire Nest to Vaillant Combi Boiler?

[RandomGrinch]

2. Then do you want me to Place a bit of cable to link the L and RT terminal?

Yes, and I would like that to be the only cable in the 230V RT terminal (i.e. no grey from the Heat link).

 

[Mr Sparkle]

Yes, and I would like that to be the only cable in the 230V RT terminal (i.e. no grey from the Heat link).

Done - The CH still operates.

FYI All of the incoming wires from the nest heatlink were left in place in the terminals on the boiler

Edit

Also disconnected the incoming wires from the Nest Heatlink to the boiler just in case this was asked as well.

The CH still operates

 

[Mr Sparkle]

Issue has still not been resolved.

Are there any further suggestions?

If not, can i be advised on the best person/group/company to contact to resolve this matter.

 

[RandomGrinch]

Issue has still not been resolved

Now, that's not a very constructive answer!
What happens with the 230V RT linked, does the heating come on, or stay off?

 

[Mr Sparkle]

Now, that's not a very constructive answer!
What happens with the 230V RT linked, does the heating come on, or stay off?

The heating comes on.

 

[RandomGrinch]

The heating comes on.

Isn't that what we want?

You said earlier that without the link and with 24V RT removed, the heating was off...

- All wires were removed from 230V RT terminals

- 24V RT Link was removed

I can confirm that the central heating does not work

Now with the 230V RT link in place, the heating turns on.
Remove the 230V RT link and heating goes off.

All the Heatlink does, is act as a switch, providing a switched line to 230V RT.

 

[Mr Sparkle]

What happens with the 230V RT linked, does the heating come on, or stay off?

I may have misunderstood what you were asking

230v RT linked with L = Central heating works

230v RT linked to itself with = Central heating does not work*

* I mentioned this in an earlier post but will have to double check later when. I am next to the boiler to confirm.

24v link was removed in both cases