Replacing Honeywell system with tado

[Bizzy542]

Hi, first time poster here, any help would be very much appreciated

My original system consisted of a S-plan installation with a combo boiler and hot water tank controlled by a Honeywell 6660D wireless relay controlling the central heating and a Honeywell STC9100C controlling the hot water. Please see the attached pictures of the original setup and also the internal wiring.

I currently have a tado Extension Kit installed by an electrician with both the previous connections into it. The central heating is working correctly however, the tado does not seem to be controlling the hot water valve, and we can only get hot water if I manually put the valve in the open position.

Tado have not been very helpful with configuring this situation and the electrician has checked the wiring to be correct as far as he can tell, so I’m really not sure what the problem is.

At the moment, both the N and L wires from the previous relay and programmer go into the tado N and L slots.
The black wire A from the relay goes into 2 and the grey wire B goes into 4 on the tado.
The black wire 1 from the STC9100C goes into 1 on the extension kit and the grey wire 4 goes into 3. Earth goes to earth.
I hope this made sense.

Can anyone advise if anything is incorrect in this setup? I’m wondering if the electrics in the hot water valve has blown and will get an engineer to check that if necessary but I want to be sure the wiring of the tado is correct first.

Any help would be very appreciated and let me know if any further info will help please. Thank you.

 

[picasso]

You don't need the black wire on 1, have you checked the jumper position ?

 

[Bizzy542]

Sorry I forgot to say it’s on position 2, Switched Live. This is what tado advised.

Is this correct? And are you saying on this jumper setting position 1 is not required?

 

[picasso]

You don't need either of the black wires on 1 and 2, if you have 240vac on the brown to each of the zone valves when the tado is on for heating and water then its wired and working correctly

 

[Bizzy542]

Ok that’s good to know thanks. Just as a learning point, would having the black wires in 1 and 2 cause the valves to not function correctly? I don’t understand why the CH is working and not HW.

Also can I just insulate the ends of the black wires and leave them disconnected inside the box?

Thanks for the quick responses.

 

[picasso]

If you had the jumper on position 1 the central heating would work because you have a misconnection on 1 and two, with the jumper on 2 the two black wires are not connected to any thing inside the tado

 

[Bizzy542]

Ok, so if the black wires are redundant, as the hot water is not working do I assume there is something wrong with the valve?

 

[picasso]

Check the browns of the zone valves.