Honeywell Zonal Valve to Nest Heat Link

[ianmcd]

So this is what I am going to do, any objections?

No that is completely wrong, the grey goes to a permanent live, the orange goes to the switched live at the boiler , there will already be a wire in there from the underfloor zone valve if wired correctly

 

[DP]

I would prefer to keep the orange and grey voltage free if boiler allows

cannot see why the OP is having an issue

In a nutshell the UFH needs to be on longer to maintain heat ( boiler may offer lower temperature output), this I would have a programmable room thermostat for. Radiators and hot water operating second and third motorised valve off Nest.

Saying what boiler you have might have helped ( not read all the replies though) OT there to be used but again boiler determines that and voltage free switching

 

[ianmcd]

dan read the post he OP has two circuits one under floor and one rads

 

[DP]

Jamie, think about what I am going to write here for your benefit

The motorised valve has a motor that is driven by brown and blue wires. When the valve opens fully, a switch makes in the motorised valve ( what you cal zonal valve) orange and grey wires are connected to this switch. Some boilers require and some people connect grey to permanent live terminal. If there was no demand but you operated the motorised valve manually and the switch operated ( would do momentarily), the boiler would be energised for the ON duration of switch within the valve.

Some boilers have a link across two terminals when it leaves the factory. My preference is to not connect 240 to grey wire but to discard the link and connect all the greys to one terminal and orange to the other terminal vacated by the discarded link

now look at you nest

You have N and L. Power is connected there. Then you have terminals 1,2,3 and 4,5,6

Not have access to the manual, but will be safe to say one of the three terminals will be C, another NC and third NO. When the timer is not calling C will be making with NC. When timer calls, C will make with NO. Looking at your wiring that will be happening but there are no wires connected to these terminals so cannot fathom how you are going to get the valves to open

I would connect L to all the C terminals, and then each NO to drive each of the two motorised valves

 

[ianmcd]

Some boilers require and some people connect grey to permanent live terminal

sorry dan that is the way we do it, some bespoke wiring systems are different, but a standard system is wired this way

 

[CBW]

None from me. How will the boiler know to fire up for rads though? Your switch live output (orange usually) goes to boiler switch live - this then tells the boiler to bring the heating on.

This post was typed with some cynicism, as OP didn’t seem to grasp the switch live at the boiler concept, so I half gave up.

 

[DP]

sorry dan that is the way we do it, some bespoke wiring systems are different, but a standard system is wired this way

Sorry Ian not all the time. Can we discus in CC

 

[ianmcd]

of course mate but nothing to hide

 

[Razor900]

I'm not getting all this. The brown from the radiator 2 port valve goes to terminal 3 on the nest. There should be a link between live in and terminal 2.

The grey on the two port should be permanently connected to live and the orange is the switched live to bring the boiler on

 

[CBW]

the orange is the switched live to bring the boiler on

Yes,but OP reluctant to comprehend this

 

[ianmcd]

leading a horse to water comes to mind