Fitting Honeywell CM927 to a Glow worm Betacom 30C

[Joshwa2k]

Hi all,
Newby here, been having a read through some great threads about fitting the CM927 but haven't found anything relating to the Betacom 30C and need some help.

I currently have a Sunvic RS-1 Electromechanical Room Thermostat connected to the boiler and would like to replace it with the CM927 for greater flexability. The boiler just has an integral 24hr time clock and I would like to be able to program different times for weekdays and weekends, the thermostat is also positioned in a really silly place where it rarely reaches temperature so the rest of the house gets boiling in the process so I thought a wireless programable stat would be ideal.

So before purchasing I've had a look at different threads and also the CM927 install manual but can't get my head around the wiring configuration.
At the moment the boiler just has mains power coming in from a fused spur and 2-core cable coming from terminals 1&2 of the stat to the two 24V terminals in the boiler (which itself all seemed normal until I looked at the Sunvic stat and it says "Switch rating 230V", but hey ho all is working fine).
Where it confused my was looking at the CM927 manual Combi Boiler Wiring diagram where it seems the live connection to the boiler has to be routed through the two L terminals of the BDR91 Receiver. Is this correct and if so how would one go about wiring this up, with what cable etc.? And then Terminals A&B on the Receiver, would they go to the 24V terminals on the boiler much like the current stat or do they need to be wired into the 230V terminals on the boiler?

Any advice would be much appreciated, the last thing I want to do with the weather how it is, is blow up the boiler.

 

[Whitespirit66]

Don't worry about rating 230V, that's a maximum. Yours is low voltage.

The receiver needs permanent L and N that can be taken from the boiler's fused spur. Connect receiver's A terminal to one of the connections in boiler that the Sunvic connects to, and receiver B to the other boiler connection.

You will need to set the existing boiler's timer to constant to allow the Honeywell to control timings.

 

[Joshwa2k]

Don't worry about rating 230V, that's a maximum. Yours is low voltage.

The receiver needs permanent L and N that can be taken from the boiler's fused spur. Connect receiver's A terminal to one of the connections in boiler that the Sunvic connects to, and receiver B to the other boiler connection.

You will need to set the existing boiler's timer to constant to allow the Honeywell to control timings.

Great, so effectively I can leave all wiring to the boiler completely as it is (which would be preferable as that to me is the scary bit), I just need to get a permanent L and N to the Receiver which as you say I can take from the fused spur, then use the wiring that currently exists for the Sunvic stat to wire in Terminals A & B on the new Receiver?
Once installed, if I understand correctly, I would just switch the boilers integral timer onto constant and let the CM927 do the work?

 

[Whitespirit66]

Don't worry about rating 230V, that's a maximum. Yours is low voltage.

The receiver needs permanent L and N that can be taken from the boiler's fused spur. Connect receiver's A terminal to one of the connections in boiler that the Sunvic connects to, and receiver B to the other boiler connection.

You will need to set the existing boiler's timer to constant to allow the Honeywell to control timings.

Great, so effectively I can leave all wiring to the boiler completely as it is (which would be preferable as that to me is the scary bit), I just need to get a permanent L and N to the Receiver which as you say I can take from the fused spur, then use the wiring that currently exists for the Sunvic stat to wire in Terminals A & B on the new Receiver?
Once installed, if I understand correctly, I would just switch the boilers integral timer onto constant and let the CM927 do the work?

Yep, that's it.

 

[Joshwa2k]

Great,
Glad I asked rather than accepting the local plumbers quote for £200.00 ExVAT to supply and fit, considering you ca buy online for about £105.00 Inc.VAT.
Thank you for your expertise and extremely prompt reply.