How to wire greenster 30si combi, siemens rwb30e controller and esi esrte2 room thermostat.

[Paul Stride]

Hi, can anyone tell me how to wire greenster 30si combi, siemens rwb30e controller and esi esrte2 room thermostat.
What cables would I need and to where, I need 3 core for room stat, is it 4 core for controller?
A basic drawing would be great.
At the moment we have a greenstar 30si combi connected to a Honeywell home controller. But I needed something simple for my dad as he gets confused. That's why I'm changing it. Any help would be grateful.

 

[ianmcd]

The wiring diagram is on page 29

file:///C:/Users/user/Downloads/Greenstar_25-30_Si_Mk2_Installation_and_Servicing_Instructions%20(1).pdf

 

[CBW]

Is there any harm getting someone in to do the job, if you’re stuck at the first hurdle?

 

[Paul Stride]

I think I'm ok with the wiring now but on the programme timer and room stat they both have terminals for earths even though they're not on wiring diagrams, can I not use the earths and this means less core cable required. Thanks

 

[MJN]

No, don't use the earth wire for anything but earthing, even if not required.

 

[Paul Stride]

But do I need to put an earth cable to room stat and controller as there is terminal for it. Or just not bother.
thanks

 

[MJN]

Both of those devices are double-insulated and so don't themselves require earthing (i.e. there is no danger of the casing being made live as a result of an internal fault) and thus if an earth terminal is present it'll serve merely as a parking terminal (somewhere to keep the stray earth wire out of the way!) or as a point to aid the provision of continuity of earthing across all the cables that enter and leave the devices. This latter use is not just helpful to provide earthing for downstream devices that may require it but also to provide protection against dangers arising from drilling/cutting into the cables themselves.

As it sounds like you're still to buy the cable then accommodate the earth in your core count - don't see it as a 'bother' - see it as a job well done (not to mention compliant with the regs which is the bottom line, but understanding the reasons behind them always helps!).

 

[stem]

It's always good to have an earth wire present, even if the current accessory is double insulated and the wire is 'parked' out of the way. Not all accessories are double insulated and who knows what may replace it in the future. It's a no brainer to include it if you are installing a new wiring from scratch.

I've come across a few heating programmers that were installed without an earth connection, that their owners have later wanted to replace with a Nest Heat link that does.

Also, whilst the devices per-se are double insulated and don't need an earth connection, often they are mounted on metal back boxes that do.