Am I wired wrong!
Hello,
So briefly my set up.
40CDi Classic Regular boiler, hot water tank, 2 heat zones controlled by Danfoss valves.
My Tado set up, Wireless Receiver X (replaced old time clock), 2 Wired Thermostats (one for each floor linked to the valves) which replaced old manual thermostat dials, and lots of Tado TRV's on the radiators.
The problems.
To make it work I have had to set my zone controller for each room to not just the relevant floors wired thermostat but also the wireless receiver (Tado support say I don't need to do this but it doesn't work if not).
My gas consumption feels like it through the roof. I only have the heating in some rooms boosting to 21 for a few hours in the evening, during daylight hours around 18, and overnight drop it down to 16 ish. Modern insulated house.
The light on the wireless receiver (heating light) seems to be on all the time??
The good.
Hot water works perfectly
How it is currently wired.
Wireless Receiver x
Downstairs Thermostat
Upstairs thermostat
Answers
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From the pictures it seems that there is a wiring centre present in the mix between the wireless receiver and the zone valves. In that case, this site: Central Heating Controls and Zoning - DIYWiki provides the drawings for the S Plus Plan. The picture below sets out how they are arranged:
In your case you'll have one two port valve for HW, and two two port valves for CH, so the wiring is a little more complicated. Note that when the controller provides power on PIN 4 the room stat passes it onto PIN 5, where it goes to power the motor on the valve. The second thermostat will also get its power from PIN 4 and transfer it to some other pin where the second motorised valve and thermostat are wired in.
Are you comfortable working with an electrical multimeter? If so, you'll need to kill the power and trace the individual wires so you know exactly where each wire originates and where it finally goes.
If thats too much work, this may help with your understanding. Each thermostat does two things (i) it wirelessly tells the wireless receiver it needs heat and (ii) it complete the circuit between COM and NO locally.
So STEP ONE: double check that when a thermostat doesnt want heat, that the NO wire is dead and that when it does, the NO wire is live. You will need an electrical testing screwdriver. Do this on both thermostats. If one or both dont do their job contact Tado support and get this fixed.
As STEP TWO disconnect both thermostats (remove the NO wire) and turn them both off. Go to the wireless receiver and confirm that the wireless receiver stops calling for heat on CH. This proves that they do work and communicate properly.
As STEP THREE, wire one of the thermostats back into place, make it call for heat. Go to the wireless receiver and confirm that it does force heat on. Then turn off the call for heat and check again at the receiver, prove that it does shut down.
As a STEP FOUR, disconnect the previous working thermostat and wire back in the one you hadnet tested, repeating STEP THREE, for the other wired thermostat. Prove it works.
As a STEP FIVE, put both thermostats back in disconnected state and now test the HW thermostat. Disconnect the outgoing wire to the HW thermostat from the wireless centre (this is the HW COM wire) and prove that the wireless receiver does not call for heat on HW. This is very likely to be proven.
In steps 3-5 you've also proven that the wireless centre does its job as instructed.
STEP 6. Go to the APP and shut down both CH zone (controlled by both thermostat). This forces the Tado backend to instruct the wireless receiver directly and also the thermostats. CH should now die.
STEP 7. If that worked, stand in front of the the wireless centre and using the app, start one zone up from the app. May take 2-3 mins for it to respond. Does it? Repeat for the second zone.
If there is a fault, at least two of these tests should fail.
Put everything back and come back here. What were the results?
One more thing- did you instruct the app and wireless receiver that this is an S Plan? If it thinks this is a Y plan, it could produce exactly what you are experiencing.
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