Worcester with Siemens RWB29 to nest E heatlink connection

[ducks78]

Hi,

Newbie here

Trying to add the Nest E to my boiler and I gave up as I thought the cover will have to come off and a rewire. But reading another thread it may not be the case.

At present, the timer has 2 neutrals, 2 lives, and I'm assuming it's heating on-demand in #4 (brown), with the blue of that cable terminated

As the siemens is mains voltage I thought it would not work with the Nest E as it's 12v but on another thread, it stated that you can put the Lives into 'C' and terminate the Neutrals

I've attached a pic of the backplate of the Siemens Timer

04ba4477-6531-4dc3-a6db-d1ed4249b6e9

• ducks78
• 13 Sep 2019

 

[stem]

You are quite right, terminal 4 of the RWB29 is heating on.

The two wires in the N terminal of the RWB2 need to remain connected connected together, but should not be connected to any of the e-nest terminals. Normally this is done by using a single screw connector and tucking it out of the way.

The e-nest has a voltage free switch with 2 terminals C and NO

The two brown wires in the L terminal of the RWB29 also need to remain connected together, and inserted into e-nest terminal C
The single brown wire in terminal 4 of the RWB2 goes to the e-nest NO

Of course the RWB29 is a only programmer. The e-nest is a combined programmer and room thermostat, so if you have an existing room thermostat somewhere, that will need to be decommissioned properly by linking out the switching contact, it cannot just be disconnected otherwise the wiring will be open circuit and the heating will not operate.

 

[ducks78]

You are quite right, terminal 4 of the RWB29 is heating on.

View attachment 171273

The two wires in the N terminal of the RWB2 need to remain connected connected together, but should not be connected to any of the e-nest terminals. Normally this is done by using a single screw connector and tucking it out of the way.

The e-nest has a voltage free switch with 2 terminals C and NO

The two brown wires in the L terminal of the RWB29 also need to remain connected together, and inserted into e-nest terminal C
The single brown wire in terminal 4 of the RWB2 goes to the e-nest NO

Of course the RWB29 is a only programmer. The e-nest is a combined programmer and room thermostat, so if you have an existing room thermostat somewhere, that will need to be decommissioned properly by linking out the switching contact, it cannot just be disconnected otherwise the wiring will be open circuit and the heating will not operate.

Thanks so much, this is going to make life easier

 

[stem]

If you do have an existing room thermostat and need any help with decommissioning it post back details of it, otherwise you are good to go.

 

[ducks78]

We only moved in a month ago and can' find a room thermostat, but some of the worst plumbing that could ever be found.

Will do this tonight and any issues will let you know

Cheers again, this should only take 10 minutes hopefully