Honeywell CMT927 wireless Thermostat + Ideal ICOS HE24

[stamjamaar]

Chaps,

looking for help please! Just bought a CMT927 to control an Ideal ICOS HE 24. The wires leading to the current thermostat is 3 core + earth. I also think it is a 24 volt system.

Therefore, I think I have messed up as the BDR91 requires 230V to work. My question is therefore how can I know get round this? How do I get a 230V supply to the BDR91? Can I change a connection in the boiler? Do I have to rewire? I'm not sure where to go from here and would appreciate some help,

Regards

Steve

 

[D_Hailsham]

I also think it is a 24 volt system.

No, it's 240V.

The 3 core plus earth is OK, though the earth is not required and should be made safe at both ends.

At the boiler end connect brown to the L terminal, blue to N and third wire to L2. Remove any link between L1 and L2.

At the BDR91 receiver, connect brown to L, blue to N and third wire to B. Also insert a link between L and A.

Job done.

 

[stamjamaar]

I also think it is a 24 volt system.

No, it's 240V.

The 3 core plus earth is OK, though the earth is not required and should be made safe at both ends.

At the boiler end connect brown to the L terminal, blue to N and third wire to L2. Remove any link between L1 and L2.

At the BDR91 receiver, connect brown to L, blue to N and third wire to B. Also insert a link between L and A.

Job done.

Thank you very much for your reply - it is really appreicated. I'm a little confused at the boiler end. I thought the wires come direct from the PCB (through the walls of the house) to the Thermostat mounting point. I take it this stays the same and all I do ist remove the link between L1 and L2 on the power connector to the boiler in order to make it 240V? Therefore my question is do I need to re-wire the boiler end too?

Regards

Steve

 

[D_Hailsham]

I thought the wires come direct from the PCB (through the walls of the house) to the Thermostat mounting point. I take it this stays the same and all I do ist remove the link between L1 and L2 on the power connector to the boiler in order to make it 240V? Therefore my question is do I need to re-wire the boiler end too?

Hopefully the boiler end will already be wired as I said, though you may find that the brown wire is connected to L1 and not L. The difference is that L1 is controlled by the boiler's On/off switch and L is permanently live. It is better to use the L terminlas as then the receiver has a permanent supply. The Link between L1 and L2 should have been removed already - I was just belt and bracing!

As long as you can identify the thermostat cable at the boiler end, you should not have any problem. Just make sure you turn the power off at the wall before doing anything!

 

[stamjamaar]

I thought the wires come direct from the PCB (through the walls of the house) to the Thermostat mounting point. I take it this stays the same and all I do ist remove the link between L1 and L2 on the power connector to the boiler in order to make it 240V? Therefore my question is do I need to re-wire the boiler end too?

Hopefully the boiler end will already be wired as I said, though you may find that the brown wire is connected to L1 and not L. The difference is that L1 is controlled by the boiler's On/off switch and L is permanently live. It is better to use the L terminlas as then the receiver has a permanent supply. The Link between L1 and L2 should have been removed already - I was just belt and bracing!

As long as you can identify the thermostat cable at the boiler end, you should not have any problem. Just make sure you turn the power off at the wall before doing anything!

D_Hailsham,

the person who installed the system used the "blue" wire as the switch live, I traced it to both ends. Your description of the wiring was "spot on" and a great help. All in order now.

A big thankyou.

Regards

Steve