Nest -heat link control wiring to Ideal Logic plus 30 boiler

[lynchnigel]

Hi all i'm just in the process of completing my Nest V3 (heat link) which is wired to my Ideal logic combi boiler.
I've done the Nest to the heat link.
I've also done the 230V from the combi to the Heat link using a 5 core heat resisting cable.
Just the control to do which i needed advice about as to where to stick them
Heat Link side:
2 is common
3 is Normally Open (NO) as per this image:
https://s3.amazonaws.com/support-assets.nest.com/images/Amber/a2-cables/a2-cables.jpg

The combi when brought comes like this:
http://i.imgur.com/DYu7ilI.jpg

Diagram B of this is the same for mine to:
http://www.manualslib.com/manual/945299/Ideal-Logic-Plus-Combi-24.html?page=30#manual
Would that mean its the Room stat - timer connections I need to take to 2-3 of the Heat Link?
Theres a voltage on the room stat connection not 230v though.

Reading this thread he says different?
https://forums.overclockers.co.uk/showthread.php?p=28876511

I just basically need the common and switched live connections iif anyone can help it would be appreciated

 

[lynchnigel]

Do we not have any sparkies to help?

 

[lynchnigel]

Thanks very much both for helping, I will try wiring it as Hardwaregeek says and go from there.

Incidently I've ripped out the original as the wiring was a mess which had a Danfloss 240 therm but a semi nice programmer from Heatmiser and so thought I would replace the messy wiring with this with also can use the 5Ghz WIFI frequency moving forward less interference and will be able to use it with automation. If anyone is interested have a look at IFTTT what it can do with the Nest.

well illustrated joelk2 by the way they left no room for getting it wrong thank you.

 

[lynchnigel]

And looking at (which is in the manual) it does show mains going through the circuit?
We did originally have a danfloss (240v) thermastat doing exactly this originally before i ripped out the dodgy wiring.

 

[lynchnigel]

Guessing the heat link can handle both mains and volt free switching, never fitted a nest but hive can do both.

Main or not depends on the boiler not the stat - in the boiler connections pic where the stat connection is linked out, boiler maybe supplying mains and expecting mains back or maybe supplying 12v or volt free and putting mains down there may do damage

if you remove the link between the 2 room stat connections and run 2 cores, one from each stat terminal and have the heat link switch those then you cant get it wrong afaik, looks like in that pic would be left and right room stat connections for voltfree

or you could measure voltage to see it if is mains and then run only 1 core as in the manual you linked and take mains from the supply to the heat link

Indeed I'm of the same mind, better low or no volts rather than 240V and if it works all the better

 

[lynchnigel]

Yep squirting the voltage from the far right side (Room stat /timer there is no link on mine) of:


using that as common on 2 of the heat link and the other on 3 of the heat link

sorted, I sort of knew but good to bounce it of people to make sure.

thanks guys.

It would have been good to use the opentherm connections, but you have to buy the harness and mess more and not sure the gain out weights the messing.

 

[lynchnigel]

I've actually (after buying a harness) that this Ideal combi already had the harness! so its now wired for the opentherm, which allows control of the hot water temperature and modulation. easy to wire and took longer to put the wiring around the sides of the boiler to the heat link.
for information - the connection is on the opposite side (Right side) when you pull the front down and the connections from the control panel need moving before anything is plugged in and damages the PCB board.