Nest Wiring Help Please

[Nobber]

Hello
I have a secure 302 channel wireless receiver connected to my boiler it just fitted over the standard backplate when I removed the old programmer some years ago, it is paired with a wireless thermostat, I think I linked two connections together in the central heating wiring centre when I replaced the old wired thermostat but can't remember which ones, so everything work ok at the moment but I want to replace the thermostat and receiver with a Nest to control Heating And HW

This is from the receiver manual

This is what I have when I remove the old receiver above

So if I move the L N Wires to the correct L N on the heatlink and link L to 2 and 5

No 4 above is Heating and No3 HW

So yellow no3 above goes to no6 and blue no4 goes to no3 is this correct?

I want the Nest to connect via Wireless to the heatlink is there anything I am missing here

Thanks

 

[piglet11]

I'm not going to advise if your wiring is right or wrong, only to say when you disconnect something, make sure you record what goes where, either by writing it down, marking cables or photographing the layout.
The photograph of the old backplate is too much of a rat's nest of wiring to be sure what goes where.
Your small image of the Secure SS302 programmer tells you that the 302 does not have voltage-free contacts. It says there is an integral connection and is suitable for mains voltage only.
What that all means is the red connections you have drawn are already connected internally in the 302. You could confirm that with a multimeter.
Both the Nest and Secure manuals are available by a browser search.
What you need to do is confirm whether the boiler end of the Nest has voltage-free or internally linked contacts.
You can be sure that the UK version of the Nest will be compatible with UK standard heating and hot water wiring.
Provided you didn't move any wiring positions when you fitted the Secure unit, it should work fine as it is with the Nest, but you must compare the Nest and Secure installation wiring to be sure.
If the Nest is voltage-free you will need the red links as you drew - if not, confirm that the Nest has internal links.
If you changed wiring in the wiring centre, then you could have a problem. It's much clearer if you make links where they are meant to be.
It would help if you said what sort of system you have i.e. does it have a 3port motorised valve (Honeywell Y-Plan) or two 2 port valves (S-Plan).
I'm assuming you have a three wire cylinder thermostat.
Some room thermostats are two wire, i.e. just a switch - some are three wire, with a neutral, permanent live and switched live.
Never assume that plumbers or electricians or homeowners follow instructions.

 

[Nobber]

Ok thank you for the reply