new programmer wiring

[Paulbacca]

The Honeywell ST699 timer in my elderly parents home has burnt itself out. I've bought a Siemens rwb29 but the wiring guide does not say where to move all the wires I have. In addition, it looks like the earth wire is not being used for earth but something else. Besides the N & L there are 2 black wires and the earth wire.

Here is the current wiring for the ST699:
View media item 64740
This is the rwb29 diagram:
View media item 64741
Thanks

Paul

 

[Dan Robinson]

Why are 5 & 6 linked in your ST?

Normally I would say:

HW S

L - L

N - N

7 - 1

6 - 3

3 - 4

But something looks funny on your ST panel.

 

[Charnwood]

Hell's Bells! I would be ashamed of that wiring if I'd done it.
Half the wires are barely touching the retaining screws.

 

[D_Hailsham]

Why are 5 & 6 linked in your ST?

Probably because it is a pumped CH, gravity HW system.

Take a look at Basic System 1, 2 and 3 in the ST699 Instructions

If that's the case, the RWB29 is not suitable.

 

[Dan Robinson]

Cheers D - didn't have those to hand.

 

[Paulbacca]

Yes it looks like the ST is wired for basic system 1.

It's a bit misleading that the rwb29 is listed as compatible with st699 installations.

What timer would you recommend?

 

[Paulbacca]

I have just found this document that seems to say that the rwb29 can operate a pumped ch and gravity hw system.

Please could you have a look and see if this is possible and what the wiring should be?

http://www.industry.siemens.co.uk/b...-controls/documentation/Documents/rwb29_d.pdf

Thanks

 

[twgas]

There's a dip switch on the swm29 to set it for gravity hw, do you have a C plan (gravity hw controlled by a 2port valve and cyl stat)?

 

[twgas]

Sorry, duplicated post

 

[RF Lighting]

You need to gwet that wiring sorted out. Currently you have an earth wire connected to a live terminal, which is both dangerous and not allowed.

You do have enough wires to wire this up properly with out too much trouble.

 

[Paulbacca]

I realise this wiring is not very good and needs to be rewired but the timer, ch and hw have been operating as it should. It does look like the earth wire is not being used as an earth.

I think I need to trace the wires back and find out exactly where they all go.

 

[doitall]

I realise this wiring is not very good and needs to be rewired but the timer, ch and hw have been operating as it should. It does look like the earth wire is not being used as an earth.

I think I need to trace the wires back and find out exactly where they all go.

The existing is all wrong and needs to be sorted first.

I guess the only reason it works for hot water is the loop wire 5-6 which shouldn't be there

 

[Paulbacca]

Do you mean the wiring needs to be completely replaced right back to the junction box with new cable? What cable should be used for this job. Is there a standard 5 or 6 core cable that can be used?

 

[doitall]

I would say yes to both questions, as it looks like it's been bodged to get it working.

Multicore is best.

 

[D_Hailsham]

I guess the only reason it works for hot water is the loop wire 5-6 which shouldn't be there

The loop from 5 to 6 should be there - see my earlier reply.