Add tuya wifi thermostat to Honeywell wiring centre, how?

[DiscoVolante]

I bought one of those cheap chinese wifi thermostats that I'm trying to add to our Honeywell ST9400C S-Plan CH system. Thing is the Honeywell Wiring Centre has made this impossible for me to figure out.

The stat has NC NO L N 230v connections (see image, contacts 5 6 7 8 )

While the wiring centre has a ROOM STAT block 1 e 2 3, with 1 and 3 bridged (no stat in system) and links L1, L2 and L4 cut. (cut L1 = programmer, cut L2 & 4 = S Plan),

The stat will have its own L N connection, but how do I wire it into the Wiring Centre - presumably it goes between ROOM STAT 1 and 3 to turn the CH valve on and off? But how?

 

[stem]

Volt free boiler switch wires from 3 & 4, go to and replace the wiring centre link between 1 & 3, it doesn't matter which way around they go.

Add the permanent N and L

If the existing programmer has heating on/off time control it should be set to be permanently 'on' 24/7

 

[DiscoVolante]

Aha ... I assumed I couldn't use the volt free switch bc the WC is a 230v supply to the CH valve and not meant for high voltage.

 

[EFLImpudence]

"Volt-free" (poor term) just means it is not connected to the supply and you can use it for whatever voltage you need - within reason.

 

[DiscoVolante]

Ah, perfect explanation, thanks!