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By MarkW
We have a Y plan system which was moved over to a Tado controller when they first came out. At that time Tado provided an engineer to install for free. I never felt the water / heating was working right since when water being heated the central heating would not heat (valve not selecting mid position). Having just upgraded to Tado V3+ have looked at this further and from what I've read about Y plan and the three position valve the issue is down to the room stat being removed (since now part of Tado system) and thus there no longer being a resistor across the valve when heating needed. I've sketched out the wiring as it is now which seems possibly overly complicated and attached photo + photo of Tado wiring + Tado schematic. If someone could advise if my diagnosis correct and if so what part is needed and where to connect to get the valve to select mid position. Any other comments on the wiring welcome too of course! I'm confident with re-wiring in the junction box but not a heating engineer. In the diagram the 'Pump' is assumption on my part but only thing left when everything else accounted for! Note I've also left the earth wiring off the diagram to keep it cleaner but are all brought together in the junction box on additional terminals of the mid placed connection block.

Thanks all for any help. Mark
Tado wiring
Tado-Wiring.jpeg (194.24KiB)Viewed 5433 times
Tado Mode.jpeg
Tado operation
Tado Mode.jpeg (134.58KiB)Viewed 5433 times
Junction box wiring
Wiring.jpeg (173.18KiB)Viewed 5433 times
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