Google Nest Install - Replacing ESI ESRTP4RF on Vailiant Combi Ecotec plus 835

[Flinty43]

Hi folks.

I'm looking to install a Google Nest to replace the ESI ESRTP4RF on my Vailiant ecotec plus 835 combi boiler.

Having looked at the way in which it's set up currently it's as attached. The two cables coming into this are the mains input (right) and the boiler (left).

Do I need to replicate this on the nest? Is 3 wires to a single terminal ok?

Thanks in advance.

 

[stem]

The wires move from the ESi terminals to the terminals of the Nest that have exactly the same function. Including the brown link

Esi N = Hive N
Esi L = Hive L
Esi 1 COM = Hive 2 Heating Common
Esi 2 N/O = Hive 3 Heating call for Heat n/o

Is 3 wires to a single terminal ok?

There's no issue with with putting 3 wires in one terminal per-se, provided it can be done safely and there are no strands of wire poking out that could cause a short circuit. Nest is notoriously difficult with its small terminals even for those of us that are used to it. It may be easier for you to put the 3 wires in a separate screw connector and then just run 1 wire from that to the Nest terminal.

Alternatively, you could also split the live wires 2 and 2 instead of 3 and 1 as they are now. As both terminals are connected via the link, they are electrically speaking effectively in the same terminal.

 

[Flinty43]

The wires move from the ESi terminals to the terminals of the Nest that have exactly the same function. Including the brown link

View attachment 337494

Esi N = Hive N
Esi L = Hive L
Esi 1 COM = Hive 2 Heating Common
Esi 2 N/O = Hive 3 Heating call for Heat n/o



There's no issue with with putting 3 wires in one terminal per-se, provided it can be done safely and there are no strands of wire poking out that could cause a short circuit. Nest is notoriously difficult with its small terminals even for those of us that are used to it. It may be easier for you to put the 3 wires in a separate screw connector and then just run 1 wire from that to the Nest terminal.

Alternatively, you could also split the live wires 2 and 2 instead of 3 and 1 as they are now. As both terminals are connected via the link, they are electrically speaking effectively in the same terminal.

View attachment 337498

Thanks for the advice! Swapping it so that 2 max is in a terminal may help. If I were to go with a connector is there any type you'd recommend for this?

 

[stem]

Usually whatever I can find in my toolbox. Standard screw connector usually.