Connecting Nest Heat Link to Combi Boiler

Dancaw

Hi Im Looking for some advise, i've tried everything else, and i dont really want to spend £100 and wait 7 days for some one to come along and connect 1 or 2 cables.

I Have the Latest 3rd Gen Nest and i've wired the heat Link side up as instruction.

L to L (Live on Boiler Circuit Board which originally fed the DIEHL Typ 884 -1k) Timer Built in)
L to Common (2) on Nest (Link)
N to N (Natural on Boiler Circuit Board which originally fed the DIEHL Typ 884 -1k) Timer Built in)

The Bit i can't get my head around is

Point 3 on Heat Link which goes back to boiler (Heat Call Cable), i've found the Thermostat and Programmer points (2 connections) on boiler circuit board which is 72 Room thermostat and 139 Remote Timer, and they go back to the DIEHL Typ 884 to points 3 & 5 but i dont know if 72 goes to 3 and 139 goes 5 and theres to points and i only have one from NEST

so you see my delima

if any one could help much appreciated my Boiler is a Ferroli F24 B

Regards

Dan Cawthorne

Alex1983

Do you have a room stat already, if not there will be link fitted at the boiler which will be the room stat connection. Take out link and run a cable from there to your nest common and calling. If the link is inside the boiler then you need to get a gas safe guy to do it

Dancaw

Hi Alex

Thanks for the Prompt response,

No i dont have any Stats or external Programmers. Do i need to disconnect the DIEHL Programmer at all?

Alex1983

No leave it and set it to on 24/7 and wire nest into room stat connections, there will be a link there at the moment

Dancaw

Cant see anything on the circuit, maybe i'm missing something.

I've taken some images if you can spot anything : you meed to add the www as I'm not allowed to post links yet

imgur.com/a/TfUSN

Le_Kirk

Use this link and go to page 44, there you will see the circuit diagram showing the connection for the room stat as item 72 with connections 3 and 4 or a link.

Alex1983

Looking at the picture it looks like the timer has been wired into the link. Put common and calling from nest into the the connector block where the timer goes.

Dancaw

I thought as Much,

So do i still need to link the Common at the Nest?

and would i need to link the Remote Timer and Thermostat link at the Block? (at Boiler)

or Straight Connection Nest Point 3 to Thermostat, Common to Remote Timer

Alex1983

Not sure what you've done to the rest of the wiring but the simplest way is to run 2 cables from the connecter block where the timer is wired to (remove 2 timer cables) - to the nest and connect them to the nest common and calling.

Dancaw

I think Ive Done it, Really Simple - I was over complicating it i think

Nest Thermostate Connected Wirlesely to the Heat Link Successfully and talking to each other.

Power On

Contact 47 on boiler (ThermostatCall) Connected Contact 3 on Nest

Contact 139 on Boiler (Remote Controller) Connected to Contact 2 on Nest (Common)

I have to leave boiler on now. and when i turn up the Nest Thermostate, i can hear clicking on Heat Link and Boiler firing up.

I Assume its that simple?

speed106fan

Hi I just bought nest 3rd gen and I need some help to connect it to my Saturn combi boiler kdb 353stc with hot water I will try to upload so.e pics with wiring digram