Fitting an additional 2-port valve and stat

[Rad1o]

I need to fit an additional 2-port valve with a room thermostat to zone an extension.
I was advised that the room thermostat - 2-wire - should switch the grey coming from terminal 1. The valve is a V4043 which is shut when power is off.
On a wiring diagram from Honeywell I saw the brown wire switched from the grey which makes more sense to me. If the brown is life from terminal 5 permanently the valve will be open all the time, won't it.....?

 

[45yearsagasman]

You don't say if this valve will interlock with the boiler or if it will simply open and close independently.
Not sure what your terminal numbers refer to.

 

[Rad1o]

The valve and thermostat are additional. The boiler is controlled by another "main" thermostat. The new valve does not have to call the boiler. I only want the second thermostat to be able to heat the loft when the main house thermostat has switched the boiled on and is calling for heat.

The numbers refer to the 10-terminal junction box.

My question really is, do I need to switch grey or brown via the 2. thermostat and should my live for the 2. valve come from permanent live on terminal 1 in the wiring centre or the switched live from the main thermstat?

 

[Rad1o]

Done some more zone heating reading.
As my 2. ZV is situated behind a 3-port-valve controlled by the main thermostat, there is no point if the new ZV calls/activates the boiler via a live orange as the 3-port may still be closed.

As the brown and blue control the motor for the valve I do not really need the permanent live grey and orange connected.
This way the 2. stat only opens the2. valve.

Any thoughts on this??

 

[45yearsagasman]

You are correct. Simply terminate the grey and orange safely and connect the feed from your stat to the brown wire. The stat can be supplied from a permanent live from the wiring centre.

 

[Rad1o]

Thanks 45yearsagasman,

Works a treat. I have just done it.