Wiring CM927 thermostat to Honeywell Wiring Centre

[avangard]

Hi,

I want to install Honeywell CM927 thermostat (I don't currently have a room thermostat, only Landis&Gyr RWB200 programmer).
As I understand it, I need to wire the Relay box BDR91 that comes with CM927 into my Honeywell Wiring Centre. Unfortunately, I can't find the wiring diagram for this combination anywhere.

The Relay box has N, L, L, A, B, C contacts - see page 3 here: http://www.honeywelluk.com/Documents/Installation-Guide/pdf/1069.pdf
The Wiring Center has terminals 1, E, 2, 3 for "Room stat" - see page 23 here: http://www.honeywelluk.com/documents/All/pdf/Wiring Guide Issue 16.pdf
Which should I connect to which?

 

[Dan Robinson]

Those wiring centres a flicking stooopid. Designed for total numpties.

I would get rid of it personally. However, if you insist on using it:

3 - B

N to the mains N terminal

Left hand L to the mains L terminal.

Link the to L's inside the BDR.

Leave your old programmers heating switch in the off position.


I am of course assuming you can have independent heating and hot water at the moment.

 

[avangard]

Hi Dan,

Thanks for the quick response.

Should I also link right hand L and A inside the BDR? Otherwise B will not get any current.

 

[avangard]

Found a similar topic: //www.diynot.com/forums/viewtopic.php?t=221578
According to information there, Live and Neutral are also available at terminals 1 and 2 on the Wiring Centre. Which makes sense, because at the moment terminals 1 and 3 are linked by a wire that emulates a stat that is always calling for heat.

So I assume then that I need to wire as follows:
Wiring Centre 1 - to stat left hand L
Wiring Centre 2 - to stat N
Wiring Centre 3 - to stat B
And link two L's on the stat.

 

[Steelmasons]

Why are you linking the two lives on receiver as these are internally linked.

 

[Dan Robinson]

No mate - A B and C are volt free.

C - NC

B - NO.



*edit*


Doh - See where you were heading.... Sorry, Link Right L to A.


Sorry playing with the BES catalogue and not concentrating.

 

[Steelmasons]

Remove room stat connector block link 1 and 3.

Connect A from receiver (bdr) to room stat connector block terminal 1
Connect B from receiver to room stat connector block terminal 3.
Live to receiver L
Neutral to receiver N.

Leave programmer ch on 24 hours.

 

[avangard]

Hi steelmasons,

You're right, two L's are connected internally. What I meant to write was connect right-hand L and A. So it will be like this:
Wiring Centre 1 - to stat left hand L
Wiring Centre 2 - to stat N
Wiring Centre 3 - to stat B
And link right hand L and A on the stat.
So this is pretty much like the 'Burner' diagram on page 3 of installation guide http://www.honeywelluk.com/Documents/Installation-Guide/pdf/1069.pdf

Which is exactly the same as you suggested, but A is connected to live via two L's instead of being connected directly to live terminal 1.


This is under assumption that terminal 1 is Live and terminal 3 is Neutral.

 

[Dan Robinson]

Terminal 1 is switched live from the timer.

Terminal 3 is switched live back to the zone valve

Terminal 2 is neutral.

 

[avangard]

Thanks for clarifying this Dan.
So I have a choice of the following two options then:
1) connecting receiver L to Terminal 1 and switching CH on for 24hrs on the programmer
2) connecting receiver L to Live on the Wiring Centre. CH setting on the programmer will be ignored in this case.

Either one should work, right?

 

[Dan Robinson]

Yep.

 

[Steelmasons]

Thanks for clarifying this Dan.
So I have a choice of the following two options then:
1) connecting receiver L to Terminal 1 and switching CH on for 24hrs on the programmer
2) connecting receiver L to Live on the Wiring Centre. CH setting on the programmer will be ignored in this case.

Either one should work, right?

Connect receiver L to perm live
Connect receiver N to neutral
Connect receiver A to terminal 1 or link receiver L and A , if linking L and A at receiver then CH channel at programmer will be redundant , if A to 1 then programmer CH channel.will be active.
Receiver B to term 1.

Remember to remove link 1 and 3 at room stat terminal block.