Salus to Nest Wiring Help Please

[arsenal401]

Hi all, i couldn't quite see an answer to my question so thought id quickly ask here.

Anyway, about to install a Nest 3rd Gen and was hoping someone could confirm wiring for me please from my Salus to Nest.

What's confused me slightly is the link wire between Com and L. Where doea that go on the Nest?

Many thanks in advance.....

 

[RandomGrinch]

What's confused me slightly is the link wire between Com and L. Where doea that go on the Nest?

Occasionally, installers add links that may be superfluous anyway - however, your system appears to have two blue wires in the N terminal.
This suggests that the Salus power could possibly be daisy chained (say between the FCU and the boiler).
Connecting the wires in this configuration allows the Live wires to be connected with only two wires per terminal, rather than trying to squeeze in three in one terminal, and only having one wire in the other.

Try:
L in Salus to L in Nest
2 N's to N
COM to Terminal 2
NO to Terminal 3
Then add the link between L and Terminal 2
(take care as the Nest terminals are a bit small).

Additionally, if you intend to use terminals T1 and T2 in the Heat Link to power the thermostat, you should also connect an earth wire to the Heat Links earth terminal (as per the instructions!).

 

[arsenal401]

Thank you very much, i'll give this a try later in the week when i have some time.

Quick follow up question though.... I thought the Nest will have power already through the existing wiring i have and i won't have to provide any further power? Is that not the case? How does my current Salus receive it's power? There are no additional wires powering the salus unit to the boiler.

What are the T1 and T2 terminals for in the Nest?

I might be getting myself a bit confused

Again any help very much appreciated.

Many thanks

 

[RandomGrinch]

Quick follow up question though.... I thought the Nest will have power already through the existing wiring i have and i won't have to provide any further power? Is that not the case? How does my current Salus receive it's power? There are no additional wires powering the salus unit to the boiler.

What are the T1 and T2 terminals for in the Nest?

I might be getting myself a bit confused

The 3rd Gen Nest comes in two parts; the Heat Link, that usually mounts near the boiler, or in your case replaces the Salus, which switches the boiler; and the thermostat itself - this is powered separately from a USB supply, or a 12V feed coming from terminals T1 and T2 on the Heat Link.

 

[arsenal401]

Perfect thank you. Understood.

The thermostat will be in another room powered via a usb supply, therefore no T1 abd T2

Thank you so much for your help.

I'll post back here once all up and running

 

[arsenal401]

Installed perfectly. Thank you @RandomGrinch