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

[GodKnows]

OK,

Firstly, if you aren't sure about the wires, go to page seven on the honeywell website for the cm927, that shows where the wires need to go. But, if you aren't use to wiring these up you need a sparky or a gas engineer at the very least. The main L + N + E needs to be wired with the electric off otherwise you run the risk of blowing the boiler and frying the board not a cheap item to replace

Batter your eyelids at the gas engineer he might only charge a minimal fee, better to be safe than sorry. I applaud your diy skills by the way Always be careful with the electrics please...

 

[BellyDancingGirl]

Hi Godknows

I did flutter my eyelashes at the BG engineer and he told me which wires to connect to the receiver and said I could do it myself and save the money! Unfortunately, however, I did not have the unit at the time or I might have pushed my luck further and asked him to show me exactly what to do! I've also had another heating engineer come round and he said I was more than capable too! I just want to be 100% sure before I start moving wires around.

I would always switch off the main electrics, but thank you for mentioning it, as well as white carpets - how did you know?!

I'm just stuck now about where this extra cable goes and what I do with the CI/SL wire.

I'm virtually fluttering my eyelashes to try and get a nice sparky to help me on here!!! I even posted a picture in case that helped!

 

[cider]

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)?

just found this post. yes correct on live and neutral bit. Other wires join to A and B on stat and old terminals on boiler C1 and CL (doesnt matter which to which as just a switch circuit both ends) there may be no earth on receiver if double insulated.

Nice picky, if its an electrician you want try electrics instead of plumbing

 

[BellyDancingGirl]

Thank you - twice!

I've just had another look at the boiler and just realised that we may be at cross purposes (my fault). I was talking about the N and L as in the CN and CL where the manual timer wires into now. I think I have it, but could you please confirm the following is correct?

1. I disconnect the three wires that run from the existing clock timer, namely CN, C1 AND CL.

2. I leave in the mains power cable which currently connects into the N and L on the far left.

3. I take the new 5 core flex and JOIN the brown and blue wires into the existing terminals N and L on the far left.

4. I take one black wire and wire it into CI of the boiler and put the other end into A on the receiver.

5. I take the other black wire and wire it into CL of the boiler and the other end into B on the receiver.

6. The CN terminal on the boiler is now empty.

7. Neither end of the earth cable wires into anything.

Sorry to be a pain, but I just want to be sure.

Thanks again.

 

[D_Hailsham]

1. I disconnect the three wires that run from the existing clock timer, namely CN, C1 AND CL.

Correct - this will disable the internal clock

2. I leave in the mains power cable which currently connects into the N and L on the far left.

Correct

3. I take the new 5 core flex and JOIN the brown and blue wires into the existing terminals N and L on the far left.

Is that 5-core including earth or 5 core plus earth? If you have not bought the cable, you only need 5-core including earth.

4. I take one black wire and wire it into CI of the boiler and put the other end into A on the receiver.

No! Wire CI to B

5. I take the other black wire and wire it into CL of the boiler and the other end into B on the receiver.

It should be the A terminal. However, this is not necessary if you use a 4 core-plus earth. Just link the L and A terminals in the receiver with a short length of wire.

6. The CN terminal on the boiler is now empty.
7. Neither end of the earth cable wires into anything.

Both Correct.

You should protect both ends of the earth wire so they cannot accidentally touch a live wire - insulating tape will do.

 

[BellyDancingGirl]

That is FANTASTIC. Thank you so much D_Hailsham.

I have ordered a 5 core flex (including earth) which should arrive tomorrow so I will try it on Saturday! I'm glad I checked, as someone said earlier that it didn't matter about the A B thing and I never would have guessed about putting tape around the earth wires.

Just one last question, is it ok to connect the CL to A for simplicity - rather than putting a little bit of wire in between L and A?

Thank you, thank you and thank you again to everyone - I shall let you know how I get on. xxx

 

[D_Hailsham]

as someone said earlier that it didn't matter about the A B thing

The switch in the receiver connects A to B (call) or A to C (satisfied). In most cases, it does not matter about which way round A and B are wired. But the Instructions show A as the live and B as the switched live, so anyone working on the system for the first time will expect it to be wired that way round.

is it ok to connect the CL to A for simplicity - rather than putting a little bit of wire in between L and A?

No problem at all! It's just that 4-core cable is cheaper than 5-core and will do the job just as well.

 

[BellyDancingGirl]

Thank you so much again D_Hailsham - you can't imagine how grateful I am.

I've drawn myself a nicely coloured diagram for simplicity and can't wait to try it on Saturday (maybe I need to get out more!).

I ordered 4 metres of 5 core wire (as I'm not sure where to put the receiver yet!) for £8.50 including delivery - so I've still saved over £70 (or £110 if I used British Gas) - HURRAH!

I'll let you know how I get on.

 

[BellyDancingGirl]

It works perfectly!!!! Thanks everyone! xxx