Honeywell wireless cm927 wiring

[ash1212002]

please could you advise if possible what type of wire would i need to wire the relay to my Mini C24 boiler?

because i guess all wiring has live neutral and earth? so what do you do with the earth wire?

i have also some spare wire from an 5 metre extension lead, could i use that and just seal the Earth with some insulation tape?

also am i correct in saying its just 2 wires Live and neutral that go into the relay and that live goes into volt free terminal on the left hand side and Neutral goes to the far right of the terminal and the middle terminal you leave untouched

please advise

 

[D_Hailsham]

please could you advise if possible what type of wire would i need to wire the relay to my Mini C24 boiler?

because i guess all wiring has live neutral and earth? so what do you do with the earth wire?

i have also some spare wire from an 5 metre extension lead, could i use that and just seal the Earth with some insulation tape?

also am i correct in saying its just 2 wires Live and neutral that go into the relay and that live goes into volt free terminal on the left hand side and Neutral goes to the far right of the terminal and the middle terminal you leave untouched

please confirm

The CM927 Installation Instructions are very clear but, as you obviously don't have them, you can read them HERE

If you have a standard boiler it is diagram 4a; but, if you have a combi, follow diagram 4b.

You will need either a three core plus earth cable or a four core plus earth (you could also use two 2-core cables).

Although the earth is not used, do not make the mistake of trying to use the earth wire as one of the conductors. Just cut it short and put insulating tape round.

What type of extension cable are you talking about? Is it the orange type? The important thing is how hot the cable can get. If you are running the cable near hot surfaces, such as into the boiler, you need the correct grade of cable otherwise the insulation could melt.

 

[ash1212002]

whats the difference between

three core plus earth cable or a four core plus earth and 2-core cable?

its white a extension lead

 

[D_Hailsham]

whats the difference between

three core plus earth cable or a four core plus earth and 2-core cable?

its white a extension lead

I am slighly concerned that you are asking questions which are self-answering; but here goes.

A three core plus earth cable has four cores in total, which usually are: brown, blue, black (or some other collour) and earth which is bare wire.

A four core plus earth is similar to the three core but it has an extra core, yellow or another colour.

Two core cable just has two cores: Brown and Blue.

If you don't want to go to the expense of buying the 3-core or 4-core you could use two separate two-core cables to do the same job.

 

[ash1212002]

i guess it would be pointless using 3 core or 4 core when 2 core can do the same job! thanks

thanks for the manual for the honeywell thermostat installation sorry to be a pain i have a combi boiler with volt free terminals, would you know where live and neutral goes into the thermostat relay?

 

[bengasman]

i guess it would be pointless using 3 core or 4 core when 2 core can do the same job! thanks

thanks for the manual for the honeywell thermostat installation sorry to be a pain i have a combi boiler with volt free terminals, would you know where live and neutral goes into the thermostat relay?

apart from one 4 core cable being a lot neater than 2 cables flopping around.

the manual for both boiler and stat are very clear, if they give you problems, you would do well to get someone to do the job for you.

 

[ash1212002]

hi bengasman

i am quite confident in doing it myself, i just need some guidance am i correct is saying that i need to connect 2 wires from the relay live and neutral to the boiler wiring

and then 2 wires one on A on the relay and one on B on the relay

and then connect this to the volt free terminal?

please clarify is this is correct

 

[Chris_J]

I'm about to wire in my CMT927 and from quickly browsing the instructions, I'd say what you are saying is correct.

Essentially, you are tapping a 230v supply for the relay in the receiver unit off the boiler, so simply a live and neutral from the boiler's supply block is fine (so it's after the boiler fuse.)

Then, the relay is just acting as a switch for volt free applications, so there should be two terminals that are bridged on the boiler (see boiler MI) for a thermostat. These will be unbridged and connect to the volt free terminals of the receiver. When the stat calls for heat, the realy will complete that circuit and run the boiler.

Of course, this is a generic answer and your boiler may be different.

 

[ash1212002]

so would i require 4 core wire which shall have 4 wires to do the job?

so just to clarify live and neutral from the relay to the boiler main volt terminal

and then connect two wires to A and B to the relay and then this goes to the volt free terninal block is that correct? the volt free block has a bridge of wire from terminal 3 - 1 so i remove this and connect the wires does it matter which way i connect the wires to the volt free terminal block?

 

[Chris_J]

You would use four-core to keep the installation looking neater, as it combines it into one cable. My boiler already has a two core cable coiled up and bridged which is for the thermostat switch, so I'll be using this, plus an exta length of T&E for the supply to the relay.

Yep, live and neutral from boiler terminal so it uses the same fuse. The polarity of the two volt free wires shouldn't matter, but correct me if I'm wrong. I can't comment on exactly which terminals on your boiler the volt free connections should go, as I'm not familiar with your boiler. I would suggest reading the MIs to ensure you've got the right ones. Don't just guess, check the wiring diagram.

Of course, isolate your boiler before attempting any of this.

 

[ash1212002]

Thanks Chris for confirming everything to me

the terminal volt free block has wire which is linked from terminal 3-1 so i shall remove this and connect the wires to the volt free link, as you have said they cam go in any way

the boiler i have is a ideal mini c24

 

[Chris_J]

Have you started wiring it in yet?

I've just had mine come through the post now sat on my desk. I'll give it a go at wiring it up tonight.

My boiler is an Icon 23T. Wiring schmatic is not the best!

 

[ash1212002]

i tried to wire it up yesterday, but didnt know until you confirmed to me 4 wires are required thought it was 2

so shall have a go on monday

i am going to drill mine directly into the wall without a mounting box

you can make a hole under the relay so you can feed the wire through to the relay connections, so then it can be flush against the wall witout the need for a mounting box, found it very ackward though to wire the wire into the relay connections

by the way where would be the best place to get 4 core wiring from? checked wickes and screwfix cant see any 4 core wiring available for sale on their websites

let me know how you get along