Wiring a volt free stat to my new Heatline boiler?

[bobmnakee]

We have fitted, a Heatline Monza 24KW condensing combi boiler. It has 24v and 240v connectors, although I'm lead to believe the 24v is just for the boilers built in controls.
The programmable thermostat is a Homexpert(Honeywell) THR870CUK, 7 day program, two wire, 'VOLT FREE' jobbie, that requires two AA batteries. It can be wired to 24v or 240v.
On the boiler there is a loop connector on the 24v 'RT' side which I have removed. On the 240v side there is a 'L' 'N' & 'E' for the mains, and on the same block 'RT' room thermostat and 'FP' frost protection.
The 'VOLT FREE' stat has two sets of terminals. First block has 'A' 'B' & 'C', the second block has '1' '2' '3' & '4'.
My question is this; where do I wire the 'VOLT FREE' stat? I'm begining to wonder wether I can only wire a mains volt stat to this boiler??
I'm guessing if it's possible I would wire it up as per 'BASIC BOILER' on the Homexpert manual, and wire 'A' from the stat to the 'RT' terminal on the boiler, and 'B' on the stat to the 'LIVE' on the boiler?

I can't post the links to the manuals, but they are easily found on google.

Many thanks in advance for your help, as I'm at a loss.

 

[jaydee81]

wire it as shown in manual for combi boiler remove 24v link in boiler and connect stat in its place using a + b

 

[markythesparky]

It would be helpful if you could post a picture but ill try anyway.

Volt free contacts on boilers just measn that there is no voltage applied to it from inside the boiler. if you were to link this out the boiler would fire but there is no voltage coming from each termnal.

 

[Des 56]

I'm begining to wonder wether I can only wire a mains volt stat to this boiler?

wire 'A' from the stat to the 'RT' terminal on the boiler, and 'B' on the stat to the 'LIVE' on the boiler



Follow the good advise given and just be sure that under no circumstances must a 230 volt supply be connected to the removed no volt link connections

A new circuit board could be very costly

 

[bobmnakee]

It would be helpful if you could post a picture but ill try anyway.

Volt free contacts on boilers just measn that there is no voltage applied to it from inside the boiler. if you were to link this out the boiler would fire but there is no voltage coming from each termnal.

I'm new on here and it won't let me post links or pics, sorry.

The manual for the boiler doesn't mention anything about volt free connections. Correct me if I'm wrong but are you say that where the loop wire was on the boiler is where the two wires for the volt free stat should go? That would be on the 24v side? To be honest the boiler instructions are ****!

Sorry to be a pain but if you google search for the manuals, they're dead easy to find.

 

[markythesparky]

Yep probably. With out seeing it, it's a bit hard to be sure though.

 

[bobmnakee]

Just to up date on the trouble I'm having with the boiler instructions. The link wire on my boiler was on the 24v side, on the instructions online it was on the 240v side between RT and FP terminals? On my instructions here it shows it on the 24v side but noton the 240v side! Confusing I know!

So to clarify, do I still need to just replace the link wire with the stat wires on the 24v side? Someone told me that was just for the boilers own built in controls? But that doesn't add up to me.

 

[bobmnakee]

If I just do six more random replys I think I can then post a link for the instructions.

- - - Updated - - -

If I just do six more random replys I think I can then post a link for the instructions.

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[bobmnakee]

If I just do six more random replys I think I can then post a link for the instructions.

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- - - Updated - - -

If I just do six more random replys I think I can then post a link for the instructions.

4
​

 

[bobmnakee]

There is method to my madness lol
Here is a link for the boiler manual page 19

http://www.heatline.co.uk/assets/bo...onza 24 and 28 Installation and servicing.pdf

and a link for the stat manual page 12

http://www.homexpertbyhoneywell.com/Documents/EN Manuals/THR870CUK-EN-d05.pdf

 

[markythesparky]

Ok I've just had a look at the service manual.
You have two option for room stats on this boiler

1.
Connector X1
Remove link from RT to FP
Take a live from the 230v phase feed cable and run it to an appropriate 230v stat. Then from the 'call for heat' terminal on the stat, connect to RT. the same set up would apply for a frost stat but connect to FP

2.
Connector X17
These terminals are for specific Heatline accessories and will make the boiler more efficient. Do not use these unless you have these specific accessories.

My brother has just installed an Atag boiler and these options and layouts are surprisingly similar.

 

[bobmnakee]

Ok great thanks. So can I use this HOMEXPERT thermostat I have to wire to connector X1?

A link for the stat manual page 12

http://www.homexpertbyhoneywell.com/...CUK-EN-d05.pdf

 

[markythesparky]

yes. its a standard programmable room stat. use A and B. 230v to A and then switched from B to the boiler. i would say that you would have to reinstall any links you took from the X17 conector otherwise it wont fire.

 

[bobmnakee]

Thank you very much for your help with this. With out trying to confuse things, would it be right to have one 3core and earth flex from a junction box, and have the stat wired to that instead of the boiler? I know it would work, but would it be right by regulations?

 

[markythesparky]

you could do that. in fact thats what the service manual says to do. youd be best to run a 4 core to the boiler though. L N E and Switch from stat.