wiring for honeywell cm927 programer to a worcester 36cdi

[Plumbhandy]

Hi I'm wondering if anyone can tell me the correct wiring for a honeywell cm927 programmer. Going to a worcester Bosch greenstar 36 CDi compact. Have wired it already , but boiler can still be controlled by front panel and the temperature can be turned up and down by the controller. I have L1 going into low voltage terminal 1 on the boiler, it is coloured green with a breaker pic on it, and I have connected L2 to low voltage terminal 2. On the boiler, which is orange in colour and has a pic of a room stat on it. Im thinking it's obviously wrong, the diagram for honeywell states L1 and2 to 1 and 2 on boiler? Help would be appreciated thanks

 

[jackthom]

Can you confirm you are talking about the Honeywell wireless programmable thermostat and are wiring the receiver/relay-box up to the boiler? If so, I'm not seeing where your reference to L1 & L2 comes from and would have expected connections to terminals A & B in the Honeywell for the boiler control.

I also suspect you may have to use the 230V connection panel in the boiler to hook up to the Honeywell.

 

[Plumbhandy]

Inside the honeywell rf receiver there are low voltage connections L1 and L2 it then goes to say that they should be connected to low voltage connections 1 and 2 inside the boiler. This i have done, it seems to work but the boiler still seems to be calling for heat when the programmer is switched off? I have obviously missed something here. Wire one to a baxi boiler the same way last week and it's working fine, I think the worcester might be different.

 

[picasso]

If you read the instructions it says "low voltage room thermostat (NOT USED)" so thats on 1 and 2 is the bus connection so you cant use that either, as already said use the 240v connections to switch the boiler.

 

[D_Hailsham]

Inside the honeywell rf receiver there are low voltage connections L1 and L2 it then goes to say that they should be connected to low voltage connections 1 and 2 inside the boiler.

My copy of the CM921/7 installation instructions does not say anything about low voltage connections. In fact, if you look at the diagrams in Box 4 on page 3, you will see that the L terminals have MAINS voltage on them.It's needed to power the receiver!

 

[Plumbhandy]

Ok so , I'll do it to the worcester instructions , and L1 on the receiver side does not get used ,instead i run a wire from l2 on the receiver side to LR on the boiler and link live to live out on the boiler then link live to common live on the receiver and neutral to neutral on the boiler, then that should do it. Is that correct. Thanks

 

[jackthom]

Does your receiver unit not have terminals A, B & C to the right of the mains connection block ?

If you can post photos of the Honeywell receiver connections and the mains connection terminal block in the boiler then someone can help.

 

[D_Hailsham]

Ok so , I'll do it to the worcester instructions , and L1 on the receiver side does not get used ,instead i run a wire from l2 on the receiver side to LR on the boiler and link live to live out on the boiler then link live to common live on the receiver and neutral to neutral on the boiler, then that should do it. Is that correct. Thanks

I would guess that you do not have the instructions for the CM927.

So here they are.

What you are proposing to do is completely wrong.

 

[Plumbhandy]

Diagram for cm900 as follows terminals N L L then. Terminals A B C.

Worcester Bosch terminals are L N 230v out and LR with a rad pic on it.
If I could just know what goes where thanks will

 

[jackthom]

Connect Honeywell 'A' to the Live 'L' on the boiler 230V out section

and connect Honeywell 'B' to the 'LR' terminal on boiler which is the Switched Live for heating.

 

[picasso]

Connect the live and neutral in the boiler to the N and L in the cm900, connect the other L in the cm900 to A and connect B to LR (with the rad symbol)

 

[D_Hailsham]

Connect Honeywell 'A' to the Live 'L' on the boiler 230V out section and connect Honeywell 'B' to the 'LR' terminal on boiler which is the Switched Live for heating.

It's a wireless stat!!!

 

[jackthom]

Connect Honeywell 'A' to the Live 'L' on the boiler 230V out section and connect Honeywell 'B' to the 'LR' terminal on boiler which is the Switched Live for heating.

It's a wireless stat!!!

Between the receiver and the boiler?

 

[Plumbhandy]

Ok I'll give that a shot and I will get back to you guys. Thanks again

 

[D_Hailsham]

Connect Honeywell 'A' to the Live 'L' on the boiler 230V out section and connect Honeywell 'B' to the 'LR' terminal on boiler which is the Switched Live for heating.

It's a wireless stat!!!

Between the receiver and the boiler?

Read your instructions carefully. How does the receiver get its power?