Help with central heating wiring

[poonab]

Hoping that someone more knowledgeable than me is able to help with a query I have on my central heating wiring.

I recently decided to move from Hive over to the Drayton Wiser system, Hive cheekily use a different shaped backplate so I decided that as it was only 4 wires (N, L, 3 & 4) it was a job I could do myself. Preparing myself I took a photo of the Hive install:



And fitted the Drayton backplate to match:



So the issue I currently have is that I am in an argument with Drayton support over their hub, with the hub on the backplate I can hear an electrical whine/hum when the hot water light is on (pitch alters with light flashing brightness), I have also been sent a replacement hub which is actually louder than the first and also has the noise on the central heating being on.

Despite me pointing out that the noise doesn't occur if I fit the Hive hub on the backplate they are blaming the installation and also claiming that 1 (hot water satisfied) should have a wire going to it.

Can anybody tell me if the wiring is correct?

Whilst I may not know the full specifics of my CH system I do know what Hot Water / Central Heating appear to be individually switched if that helps.

[mrsimmers]

It will need the hot water off terminal number 1 connecting if you have a "Y" plan. (3 port valve)

If you have an "S" plan (2 zone valves) then this does not need to be connected.

[poonab]

Thanks for the reply mrsimmers.

Have grabbed some shots inside the airing cupboard





I believe this is the "S" plan style you mention that doesn't need terminal 1 connecting?

[mrsimmers]

Yep, that's an "S" plan