V3+ Receiver controller doesn't believe I have two control valves

johncpw

I've just installed the tado V3+ unit in place of my Danfoss FP75. The closest one the Tado app can find is what they call an FP975, which looks identical. The Danfoss runs fine with my Vaillant Ecotec plus 615 connected to a two valve system. The 615 is a combi capable boiler but not used that way - I prefer a hot water tank. The boiler thinks there is just a heating circuit but the whole setup has worked perfectly this way for around a decade. The Tado app instructions didn't give me enough detail - possibly because of this misidentification of the controller I am replacing (or maybe the boiler spec confused it?) - so I got hold of the "Pros Only" installer manual and wired the new unit as per the S-Plan diagram and powered it up. Heating works perfectly but hot water not at all.

The receiver is supposed to be configured to S-Plan out of the box but I checked and it was actually set to combi boiler (yellow light) so with some hassle (the manual instructions are slightly vague) I got it to go green (correct for my system). However the unit refuses to stay in this config and reverts to yellow combi mode. In combi mode the HW control is supposed to be inactive, which is what I observed.

I've now put the Danfoss back (all working fine) and I'm hoping someone (maybe Tado support who don't seem to have a contact number!) can assist.

cheers

John

GrilledCheese2

Yes, pretend your boiler is a system boiler. Your setup with the combi is useful, but is non-standard. The Tado setup tool will make some assumptions that are correct for the majority of users.

johncpw

A bit more research and it turns out that the FP75 is wired the same as and compatible with the FP715 not the FP975. I ran the install instructions in the App again with FP715 selected. This time the App told me to wire it up exactly as I did it last time. So I deduce the wiring was correct and the problem must be somewhere else. Maybe I need to spoof the boiler model with one that is not combi capable? Snag is I can no longer find the place where you specify the boiler model.

BARRETT

I have the Tado kit done the easy part connected to the internet,problem is how to wire the Receiver to a Worchester 24i junior or is it better to let a pro wire it in? .

johncpw

Karlo from Tado support fixed something in the config that ordinary mortals don't seem to have access to, which I believe did what @GrilledCheese2 suggested. my re-install now seems to be working fine (touch wood!)

johncpw

@BARRETT I expect if your boiler and controller are not too old (like my Danfoss) and you can find the exact models on the lists in the Tado App AND you setup is standard and if you are comfortable with DIY wiring then the App instructions are detailed enough to go with.

I realise that's a lot of ifs.

mattlang

@johncpw I have exactly the same issue as you - i can't get the receiver to stay in S-plan configuration mode and it keeps reverting to combi? How did you resolve it? I have logged a ticket with tado support anyway

johncpw

Hi Mattlang

Yes, it seems that if the Tado cloud configuration believes you have a combi boiler - because of the model number you entered when you did the install (as in my case) there is no way a customer or installer can override this. However the Tado tech support people can so they should be able to fix it fairly quickly once you get hold of them. Hopefully it will all be sorted when they deal with you support ticket.

best of luck

John

AntCW

Hello John,

V3+ Receiver controller doesn't believe I have two control valves

johncpw

19 Jan 2022

I've just installed the tado V3+ unit in place of my Danfoss FP75. The closest one the Tado app can find is what they call an FP975, which looks identical. The Danfoss runs fine with my Vaillant Ecotec plus 615 connected to a two valve system. The 615 is a combi capable boiler but not used that way - I prefer a hot water tank. The boiler thinks there is just a heating circuit but the whole setup has worked perfectly this way for around a decade. The Tado app instructions didn't give me enough detail - possibly because of this misidentification of the controller I am replacing (or maybe the boiler spec confused it?) - so I got hold of the "Pros Only" installer manual and wired the new unit as per the S-Plan diagram and powered it up. Heating works perfectly but hot water not at all.

The receiver is supposed to be configured to S-Plan out of the box but I checked and it was actually set to combi boiler (yellow light) so with some hassle (the manual instructions are slightly vague) I got it to go green (correct for my system). However the unit refuses to stay in this config and reverts to yellow combi mode. In combi mode the HW control is supposed to be inactive, which is what I observed.

I've now put the Danfoss back (all working fine) and I'm hoping someone (maybe Tado support who don't seem to have a contact number!) can assist.

cheers

John

---

View Post

You are the only person I came across here that has a similar set up to mine, which I assume is a system boiler set up? I am confused about the role the boiler plays here as it set up to run heating only, and does not turn on when the hot water taps are running. I was curious how do you use your hot water controls ? I have mine turned on for an hour in the morning and afternoon, but not sure if this necessary? Does a boiler come on when water is needed, so I only need to switch on hot water on tado when the temperature of the water drops/ cylinder runs out of water?

Thanks a lot in advance!

Anton

hugbilly

If you have a hot water cylinder it will only be heated at the times when HW is set to on in the schedule and then only if the cylinder thermostat is calling for heat (ie, the water in the cylinder has dropped below the temperature set point.)

AntCW

Thanks for replying, hugbilly. So in other words, hot water on serves as a boost function, as the cylinder should maintain set temperature by itself? What do I actually turn on then, an immersion heater or boiler, when setting Hor Water to on? I suspect it might depend on the model of the cylinder, right?
Thank you again, finding myself needing to upskill urgently due to moving to property with unfamiliar set up. Appreciate the information!