HOW DO I FIT A WIRELESS THERMOSTAT TO A WORCESTER 24I BOILER

[BellyDancingGirl]

I hope someone out there can help. I know that many have helped people for different types of thermostats and boilers, but not mine.

I have purchased a Honeywell CM927 wireless thermostat. I have a Worcester 24i boiler which is 8 years old. Although I have an installation guide for the thermostat (http://content.honeywell.com/uk/homes/Technical/CM/CM920%20Installation%20Guide.pdf) it doesn't make sense to me, as it seems to have two cables going into it. However, I was told by a British Gas engineer that I only needed to connect one cable (the one attached to the manual timer on the boiler). Even if he is correct, I'm not sure how I will get the 4 wires in the diagram from one cable!

Please, please, please can someone help me? I'm struggling to get an engineer, other than BG who want £120 to fit it. I bought the thermostat to save money, but it would be awful if I had to pay £120 to have someone fit it, when so many people say it's easy.

I'm pretty handy. I've wired all the halogen ceiling lights in my house, boarded and insulated the loft etc. I know I can do it, if someone would please help me out.

PS This is the first time I have ever joined a forum, so please don't make me lose faith! [/b]

 

[cider]

If you get the cable access cover off the boiler (bottom left i think) you will see the cable joing into the boiler (from mains) You should see a loop between 2 terminals. This is where you wire the switch part of the stat (in and out).
You can also wire L and N to existing feeds to boiler if room.
Sure someone here will have exact terminal numbers.

 

[cider]

P.S. stop shouting.

 

[BellyDancingGirl]

Thank you. However, that is a little too technical for me still. I recognise the mains (on the far left) which has the normal blue, brown and earth wires. Next to that is a cable from manual timer (which the engineer said I would use). That has three wires again - CN, C1 and CL.

Basically, I need to know which of these two cables (or maybe both) I need to wire into the receiver box (shown on the instruction manual I referred to in my question). Also, whether I need a junction box, which some threads refer to. Or perhaps I need to buy some extra cable to connect the boiler and receiver???

Any help would be greatly appreciated!

PS Sorry for the bold - I presume that's what you meant by "shouting". Just worked out how to turn it off - well I did say that it is my first time!

 

[cider]

Is the programmer on the wall or in the boiler?

 

[nicknox]

CN - Neutral
CI - Switch live
CL - Live

remove link between CI and CL

 

[BellyDancingGirl]

Hello again!

It's built into the boiler, although you can remove it. It's the original clock type with little push in markers representing 15 mins each.

 

[BellyDancingGirl]

Hi Nicknox

Thank you for your reply, but I'm afraid I'm not sure what you mean (sorry)

Do I remove any of the wires you mention from the boiler and put them directly into the receiver box? If so, would you happen to know where? There are slots for N L L adn A B C D E on the receiver box (as per the diagram I refer to in my question).

 

[cider]

ok you can dis con existing timer from terminals on right N LS LR.
and if nicknox is right (defering blame) join CN to N on boiler LS to CL and LR to C1
make sence?

 

[cider]

ignore what i said.
if thats the terminals it needs perm L and N and seperate cable to boiler for switch circuit.

 

[cider]

So live and neautral from spur / feed to L and N in receiver, disscon old timer, LS on boiler to A on receiver and LR to B on receiver

 

[BellyDancingGirl]

I'm totally confused now!

Do you mean that I disconnect the timer, put the N (CN) from the boiler into the N slot on the receiver, put the L (CL) from the boiler into the L slot on the receiver and then do something with a piece of cable from C1 to the receiver? I'm sorry that I'm not getting it!

 

[BellyDancingGirl]

Thank you Cider. Your response came through after I'd sent mine.

I see I am right on the L and N bit, but I'm not sure about what you say about LS and LR. Is LS the same as SL? What is LR as I don't seem to have one of those!

PS Thank you for being patient with me!

 

[cider]

to do it as per manufactures instructions you need to take live and neutrel directly to receiver, that can come from boiler terminals(L&N) or what ever is feeding the boiler. Then take 2 seperate cables to the switch part of the mechanism. So you will need 2 pieces of flex to join the 2 together. Or buy a length of 5 or 6 core flex.
Im sure if you phoned a local sparky it could be done for a lot less then 120 notes

 

[BellyDancingGirl]

The cheapest I can get (if he'd bother to come back to me) is £80 per hour, so I want to do this myself if possible.

If I get a 5 core flex, do I join the put the L on the new flex in with the existing wire in the L on the boiler (ie join them together) and repeat with the N? Then put the other L and N of the other end of the new flex into the N and L terminals of the receiver? If so, I get that bit! However, what do I then do with the existing SL/CI wire in the boiler and with the 3 remaining wires in the new flex (2 black and an earth)?