Tado to 'Y' Plan wiring

[Mushy1]

After much debate I opted for the Tado Wireless Smart Thermostat V3+ as it was compatible with my boiler and I liked the features. However, after asking for a configuration of my wiring from their support desk they informed me they couldn't provide instructions on wiring as I didn't have a separate thermostat. They told me it can be done but were not able to tell me how.

I purchased the Tado as I wanted to control both my heating and hot water which I can't do with my current Horstmann Centaurstat 7 controller. This acts as a room thermostat and programmer only. I know my system is a 'Y' plan and know that if I remove the Horstmann controller I will have to bridge between 4 and 5 terminals. What I am cautious about is the connection of the Tado Wireless Receiver to the 'Y' plan wiring hub. I have added the Tado wiring plan for reference. Any help would be very much appreciated

 

[ianmcd]

That wiring diagram is for S plan, not Y plan

 

[Mushy1]

Thanks for highlighting, wrong diagram added.

 

[ianmcd]

I will have to bridge between 4 and 5 terminals. What I am cautious about is the connection of the Tado Wireless Receiver to the 'Y' plan wiring hub. I have added the Tado

what terminals 4&5 ?

 

[Mushy1]

I was referring to the Y plan setup. Apologies for confusion.

 

[ianmcd]

Forget wire colours and other wiring diagrams just go with the diagram in #3 , forget everything else

 

[Mushy1]

Thank you for your help but still uncertain about of exact wiring from the Tado Wireless Receiver to the ‘Y’ plan diagram. For example, the Tado diagram requires a live feed to the boiler but on the ‘Y’ plan diagram there is only a switched live connection.

 

[CBW]

If you’re unsure, might be best getting someone in. Y plan shows switched live. What is displayed is L and N, earth is omitted, whereas on the Honeywell it shows the earth connected.

 

[ericmark]

Nest Gen 3 show a Y Plan

I would have thought any other smart thermostat would work in the same way? However you need a N/C contact, with some multi-channel thermostats there is no N/C contact.

I know EPH does allow you to use OpenTherm and motorised valves, but most do not recommend OpenTherm when using motorised valves, I have read that it will work with Drayton Wiser, but Drayton say OpenTherm should only be used on a single channel thermostat, not sure about Honeywell Evohome, I note no connections shown for OpenTherm with Nest when using two channels, since my boiler is not OpenTherm enabled I am not really worried.

The idea of both C Plan and Y Plan is as default the DHW is on, so the boiler can cool by heating the DHW by thermo syphon, with the S Plan with some boilers it can cause problems if the valve fails to open, but boiler is running, mainly due to micro switches sticking. But it can also cause problems with Y plan when micro switches stick, so no real advantage.

 

[ianmcd]

Thank you for your help but still uncertain about of exact wiring from the Tado Wireless Receiver to the ‘Y’ plan diagram. For example, the Tado diagram requires a live feed to the boiler but on the ‘Y’ plan diagram there is only a switched live connection.

Of corse the boiler requires a permanent live, this has nothing to do with Tado, Tado is an external control and only sends power to the switched live

 

[Mushy1]

So after looking at the tado Wireless Receiver connections for a 'Y' plan heating system I have drafted this wiring diagram. Does this look correct?

 

[ianmcd]

NO it is very wrong , not saying this again, wire as per your post #3 and it will work just put a permanent live to the boiler Live and everything else will work , stop making things complicated just for the sake of it

 

[Mushy1]

Sorry, I was only trying to ensure my understanding was correct after combining my current configuration with the Y plan and Tado configurations.

 

[ianmcd]

the boiler needs a permanent live to control its functions , the tado is simply a coplicated switch that tells the mid poition valve where it wants it to be, the MPV then tells the boiler when to come on , nothing more complicated than that

 

[Mushy1]

You make it sound so simple, thank you. Can I just ask that when you refer to post 3 you are talking about the Tado wiring diagram and not the Y plan example. If so the Tado receiver also has a wireless thermostat which talks to the receiver and just wondering how that will show on the Y plan wiring diagram. Thanks for your wonderful help, it is very much appreciated