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T

thomo2710

Hi all,

Could somebody please help me understand the following diagrams on wiring my new room stat into my boiler.

Boiler - Vaillant Turbomax Pro 24e
Stat - Honeywell CMT927 Wireless

Boiler wiring:
Page 17 of the following PDF link
http://neighbourconstructions.co.uk/OLDWWW/PDF/Standart%20efficiency/turboMAX_pro_installation.pdf

Stat wiring:
Page 7 of the following PDF link
http://www.plumbnation.co.uk/site/h.../honeywell-cmt927-technical-specification.pdf

Currently the boiler has a loop wire in pin 3 + 4 for the plug in vaillant timer. I know i havre to take this out.

I dont know what T1 and T2 on the stat diagram relate to on my boiler. Pin 3 and 4 going off page 18 of the boiler PDF!?
I dont know what that 10a fuse is for and where the diagram goes off too towards the left.

Boiler is currently hooked up to the mains supply via a fused spur.

Do i run a live from L to Pin 3, and a switched live from N to pin 4

The reciever unit is powered off a switched live.

My friend is confident he can do it as he is fairly competant with doing electrics but i want to clarify 100% what goes where first as he doesnt want to go ahead for deffo and turn the boiler back on with a bang before we are 100% certain what goes where.

Thanks in advance.
 
Last edited by a moderator:
ok so having another look over it am i anywhere close?

2 cables

1st cable - core 1 in pin 3 (T1) to A and core 2 in pin 4 (T2) to B
2nd cable - core 1 piggybacked into the L on the boiler board to L and core 2 piggybacked into N on the boiler board to N

The 10a fuse is what should be in the fused spur socket?

How close am I?
 
it seems pretty simple to me. The relay box requires a power supply to it, to power the wireless transmitter. so i would take this supply from the boiler feed. the thermostat doesnt require a neutral, so its just a live and switched live, so that would be terminals 3 and 4. neutrals are sometimes needed for thermostats (it makes them more accurate), and thatis what terminal 5 is for.
 
T1 and T2 are the 3 & 4 on your boiler so A connects to 3 and B connects to 4. The L & N for the receiver unit should come from the boiler supply. The 10A fuse would be in the spur unit that feeds the boiler

Just make sure the stat parameters are programmed correctly for your heating system
 
On the back of the stat and receiver you should have removeable pins or maybe switches. These have got to correspond with each other so the wireless reciever can pick up the correct frequency signal
 
Can you elaborate what you mean by this please?
Never used a room stat before so this is all new territory i am treading on.

Regards

If you follow the installer instructions you put the receiver into installer set up mode and set the parameters to suit your system and operational requirements from the installer parameters tables
 
On the back of the stat and receiver you should have removeable pins or maybe switches. These have got to correspond with each other so the wireless reciever can pick up the correct frequency signal

I think you are talking about a different controller this unit is set from the software there are no jumpers by pressing different button combinations you bind (pair) the transmitter and receiver together fitted one of these units on an underfloor heating system last week and they are very easy to set up
 
I just re-read through the installation setup and now understand that.

i only briefly glanced through it first time around and overlooked this part.

I will have a go tonight at popping this little puppy in and let you all know how i got on.

Thanks for all your replies and time

Kind Regards
 
Hey me again

Sorry to be a pain..... I'm doing this tonight and I want to get it 200% right as it's not exactly the weather to be without a boiler.

N L L on the relay box.

Boiler is run off a switched spur.

N on relay box - do I tap into the N on the boiler pcb and run the other end into the N bank on relay box.

Middle L - tap into L on spur socket to Middle L on relay box?

Right side L - single core cable from that straight to L on boiler pcb?

Picture on install only shows 2 wires - 1 in N and other in rightbside L

Thanks in advance
 
easiest way,
your boiler will have a 3core going from the spur LNE
take a 5core flex from the boiler to the receiver, so you have L and N, brown and blue
use grey from 3 to A then the black from 4 to B
done
 
I have 2 lengths of 2 core and E.

I have the 3 to A and 4 to B sorted it just the L and N I'm not certain on.

With my 2 core I thought it was Tap into L on boiler pcb to L on receiver(right side) and tap into N on boiler pcb to N on reciever.

Leaving the middle L empty on receiver?
 
Last edited by a moderator:
boiler spur only requires 3amp fuse,if you have a 3 core flex existing to pcb leave in place and add another 4 core or 5 core,remove link(all power isolated and proved(sorry but i dont know how competent u are),the link has 230v common(always 230v)on 3,with the link in 4 also has 230v,which switches the boiler heating on,so i would think u have been using the dial on the front to control it,with the extra cable pair up LL,NN,EE,3 on boiler to common(a) and (b) on reciever switches the heting on 4 at boiler(remember the link between 3 & 4,your now setting when that 230v is switched through,probably only saying what others have so apologies if i have,if your not confident with this maybe try your friend,watch him and then you will be more confident in the future.i had the same problem years ago when i first stumbled across wireless reciever i panicked as id never seen one,but when was explained i thought it was simple,its only a form of switch,common and call(230v).
 
If you follow diagram B in the stat instructions for wiring the receiver then it will work as required in your original post
 
Do I just leave the middle L empty and put the spur/boiler N into reciever N and the spur/boiler L into the right hand side L on receiver?
 

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