Intergas 36/30 combi & honeywell cm927

[Raymondo9]

Hi

New to the forums so firstly hello - stumbled open them whilst googling info on my new boiler . Looks like there are lots of helpful people / info here

I wonder if someone can help me with the following ....

I've just had a new intergas 36/30 combi fitted by a relative who is gas safe registered engineer so all good there . He's done it as a favour so I said I would sort out fitting the room stat as he's going on holiday and I'm more than capable of doing a bit of wiring ( worked in electronic test for 20 years). I have tools and a proper DVM etc . I just wanted to check exactly how I should wire it - I thought these room stats could now been powered via the boiler on a low voltage but it appears not ? The cm927 diagram just has a combi diagram example with reference to mains voltages .it looks as though it is simply a very fancy mains switch .

The boiler has 2 connectors x2 (24v) and x4 (230v) - is there a way for me to use the low voltage connector with 927? Bit confused !

Thanks in advance

 

[Dan Robinson]

L to 3
N to 4

A to 6
B to 7.



Symples.

 

[hertsboilers]

Link Intergas 2 (live) and 4 (neutral) of X2 to the L and N on the receiver of CM927. Then link 1 (switched live) and 3 (live) of the intergas boiler X2 to B and A on the receiver.

 

[Raymondo9]

Thanks for the speedy response folks. Without sounding thick why are there two different suggestions ? Dan your mention using 6/7 on the intergas but these are labelled 24v on this diagram ?

 

[Dan Robinson]

The boiler is very versatile.

Terminals 6 7 are volt free HertsBoilers is using the mains voltage switching.

Both options are valid. I prefer mine is all.

One thing I would pull HB on is the use of terminal 2 for Live. Whilst it will work, external controls should be drawing power from the boler not the main circuit.

Hence my use of terminal 3.

 

[Raymondo9]

Brilliant thanks . It's actually much simpler than I thought now you've cleared that up. I had it my head that the receiver was switching mains through a/b when actually it's a just a relay

 

[Agile]

Have they put the link to be removed in the book yet?

 

[Dan Robinson]

Good point....


Take the black link wire out from 6&7 when you fit the thermostat.


Which incidentally we can't condone as it means removing the boiler casing.


DO NOT remove the yellow link wire.

 

[Raymondo9]

Yeah I can see there is a jumper wire in 6/7 which obviously needs removing . There is a mention of this in the book and on an internal sticker

 

[Dan Robinson]

Shows how long it is since I read the boiler manual

Fitted so many now it is all second nature.


Actually - just looked at the boilers wiring diagram - they have added some extra tit bits to the PCB layout.

Must make a note to ask for some specifics from their tech support.

 

[Raymondo9]

Are there any regs I should be aware for the cabling I use to the receiver ?(in terms of cable type) ? The receiver must draw next to nothing so was just going to use some twin core mains cable which is well over rated at 5a, as for the "volt free" was just going to use some skinny control wire I have lying around too. Distance is only 40cm.

 

[Dan Robinson]

Rules say 0,75mm heat resistant flex.

Remember to give it an earth too.

 

[D_Hailsham]

external controls should be drawing power from the boiler not the main circuit.

Why?

As long as the external controls etc and boiler are fed from the same circuit and controlled by the same wall switch, it doesn't matter where they are connected. The important thing is that you only have to turn off one switch or pull one fuse to isolate everything.

 

[Dan Robinson]

Good practice.

Its how the Bunnies like to be wired as well.

All the external controls are protected by the boiler's on board fuse.

 

[Raymondo9]

Thanks . Can't earth the receiver it's an entirely plastic double insulated (I presume ) device .