Honeywell Cm927/921 -Worcester Bosch 25Si combi - old model

[NorthernBloke]

Hi all,
I thought this was going to be an easy job but it's turning out into a ball ache...grr!
I'm hoping someone can help.
I previously had a wall thermostat wired into the Ns, Ls and Lr inputs on the boiler.
Ive disconnected this and wired up the receiver box as per instructions, at least I think so!

I have a live, neutral and earth from the 5amp switched socket going into the boiler, L, N, E connections via a terminal block, where I've taken a L, N feed and run this to the Receiver unit, N and first L.

I have then run a L from the receiver to the Ls on the boiler, a N from the receiver to the Ns on the boiler and a third connection to the B input on the receiver thru the Lr on the boiler. I have then run a small wire from a L on the receiver to the A input on the receiver.

problems

1. the boiler front panel control knob is now redundant - I have permanent power...
2. the receiver isnt switching the boiler heating on - the unit itself appears to be working, as least it connects to the transmitter and goes on and off but this has no impact on the boiler...
3. I now have a flashing red light on the front panel on the heater light

all in all it's a pain in the ...

Any help appreciated..

thanks

 

[simond]

For starters, take the last piece of cable out from the Perm L to the A on the CM927 receiver.

A and B should just go to Ls and Lr, no other connections reqd.

 

[NorthernBloke]

Thanks Simon,
so no neutral connection is required to the Receiver-Boiler?
This doesnt look like the manual (option b) that came with the unit.
Ive read so many different options re wiring this up its becoming a case of wood for the trees...

 

[londonboy]

Remove the link as stated above

That link is basically shorting out the stat, ie. calling for heat 24-7

 

[simond]

This is very simple,

You connect Ls and Lr of the boiler to A and B of the receiver (either way round, labelling all cables BROWN).

You connect Live to L of the reciever
You connect Neutral to N of the receiver.

Job done, put the kettle on.

 

[NorthernBloke]

Thanks guys - all is good with the receiver. Boiler pilot light/spark is out causing the red flashing light...
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