Y Plan hot water problem

Nevstah

Hi, my first post having just installed a thermostat and extension kit to an existing Y plan system.
I'm replacing an old 3 wire Honeywell thermostat and Drayton Lifestyle LP722 programmer on a fully pumped system with separate hot water and heating. This existing setup worked fine with no issue.
The thermostat was easy to replace, with wire 1 going to COM, 3 to NO and 2 to the blank immediately to the right of COM.
the installation guide said I could use the existing back plate for the extension kit, so I changed the pin on the back to the number 2 position and fitted.
When I select hot water only, this works fine, when I select heating only, the motorised valve remains in the mid position until the hot water thermostat cuts off.
With the LP722 heating only meant just that, regardless whether the cylinder thermostat requested heat or not.
I've no clue if this is a wiring issue or a config issue, can anyone help?
Thanks in advance

[Deleted User]

Hello ,

Please contact our Support Team either via our contact form:

https://support-request.tado.com/#/contact?locale=en

Or via our Live Chat:

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Kind regards,

Joey

Skier

I had a similar issue in that the wiring instructions for the Extension Kit were incorrect. I exchanged e-mails with Tado over about two weeks to no avail. I eventually spent a day studying the wiring diagrams for the boiler, the heating system in general, the 3-position valve and how the older programmer was wired. I then wired the Extension Kit to the boiler as I believed it should be - it has worked perfectly ever since.

It would be worth finding wiring diagrams for your boiler and spending a bit of time studying your system. I found this site extremely useful: http://octaveblue.co.uk/c_heating/

Best of luck.

Blagdonboy

I am very new to Tado and wish to ensure I don't by the wrong stuff. Reading Skyer's response am I right in thinking that the extension kit wires directly to a motorised valve (sunvic in my case). From where is the cylinder temperature measured?

Nevstah

Thanks @Skier i think that's what I'll end up doing as soon as I get a moment.
@Blagdonboy i can only talk about my own experience, my system is fully pumped Yplan. The room thermostat, conventional boiler, motorised valve and cylinder thermostat, along with the Extension Kit, are all wired into one junction box.
To answer your question, yes the motorised valve is connected to the Extension Kit

Skier

Blagdonboy - An e-mail to Tado with a description of your system and what you're looking to achieve should allow Tado to come back with the products you need to buy. On the tado website you enter the details of your system in some detail and tado will come back to you with detailed installation instructions. The instructions are comprehensive and easy to follow and will be specific to your system. However, in my case these instructions, whilst comprehensive and clear, were incorrect and there were several issues. They were caused by the wiring to the 3-position valve being incorrect.

I'm not a heating engineer but am technical and comfortable with electrical and plumbing work (none of the latter involved here of course). As previously stated, I spent some time studying my system and the wiring diagrams I had in the boiler manual.