Nest installation from Honeywell sundial

[aetbaar]

Hi

I have a Honeywell sundial programmer and wireless thermostat model no st9420c on an s plan system

I am about to change it to a nest3rd gen learning thermostat and just wanted to understand which wires need to go where

I know I will be told that I need to a qualified electrician and I will be asking a friend of mine who is actually a qualified electrician to do this for me but he has little knowledge of wiring thermostats or nest specifically and hence the question and to be sure we have this right

I attach a picture of my current timer that is wired up and working as it should

You can see the ports on existing timer and this is all working fine as follows:
N coming in from mains
L coming in from mains
1 empty
2 empty
3 hot water on - this comes from the common on the hot water tank
4 ch on - this comes from the two zone heating valve - brown wire

From what I have read and understand the wires need to be changed as follows for the nest:
- N and L just go to N and L on the nest heatlink
- Port 3 from the Honeywell needs to go to port 6 on the nest for the hot water
- Port 4 from the Honeywell goes to port 3 on the nest for the central heating
I also note I need a wire to link live on the nest to ports 2 and 5 on the nest and link them up

I have attached some pictures and hope this makes sense - if someone could advise before I do this that would appreciate it

I have read up and done my research and this looks like it is right but if someone who has done this before can confirm that would be great

 

[stem]

The wiring description is all correct.

I'm not sure why you have posted a photo showing the connections for a Hive Dual Channel Receiver, when you are fitting a Nest though. Unless it's there to be representative of the existing Honeywell Receiver wiring.

 

[aetbaar]

Thanks stem

My error with the picture - I thought that was a picture of the existing Honeywell wiring

Thanks for confirming the wiring - we will have a go at this at the weekend