My Boiler is not responding to thermostat settings

GrahamB

I have my thermostat set @ 19.5 degrees and different schedules set at varying times of day or night however just recently the temperature has risen to 22.5 and the boiler seems to be ignoring the schedules and preset temperatures even Turing of the heating within the app the boiler just keeps on heating. I have had the system for 8 years without any issues until now what has gone wrong?

Bridge firmware 47.2

Smart thermostat firmware 54.20

Extension kit firmware 81.1

GrahamB

Thanks for your comments very helpful ironically it seems to be functioning ok at the moment having isolated everything and reintroduced but no real logic to what caused this in the first place, I think this maybe a recurring issue as it happened on 27October and again this week.
If it happens again I will use your recommendation of removing the EK from the backplane and see if the boiler responds accordingly
One again thanks for your help “Great customer service”

policywonk

The fact you have an extension kit suggests that that is actually controlling the boiler. Have you studied the triggers using the switches on that kit:
* whether pressing the CH button on the kit forces the boiler to start and,
* whether pressing the same button to force CH off actually stops the boiler?
Now if your problem of the boiler running on, or failing to start continue, it suggests that the thermostat is wired.

Is that true? If so, does it actuate a motorised valve? It could be your valve is stuck, needs to be freed, or it's motor head replaced.

GrahamB

Thanks for the response
My extension kit doesn’t have any buttons or switches only the pairing button ? The thermostat is wireless and I do have a motorised 2 way valve on the system which seems to be functioning ? I just don’t understand how the boiler has suddenly decided to ignore the set temperatures I have set within the app and just fires up randomly causing the heating to raise well above the set levels even turning off the CH/HW within the app the boiler still does its own thing.
If the valve is faulty how would this affect what I’m experiencing? It’s as if the thermostat is not talking to the extension kit which controls the boiler and pump

Rob

@GrahamB

Looking at your data (the account which shares your forum email address) I see that everything was fine until Nov 5th, 21:00-ish. Until that time, there was a mild heat request and the Extension Kit started the boiler occasionally. The room temperature was stable. All was well. And then suddenly, at 9, the room temperature increased quickly, despite the thermostat not asking for more heat. So that's when the issue started.

Looking at my data, the Extension Kit reports that it switched off its relay the way it should. There are also no connection issues, with the exception of Nov 6th in the early afternoon, but I presume that's when you were troubleshooting.

So I do not see a malfunction, which either means a fault at the boiler (/valves) or a stuck relay at the EK. The latter can happen, but is super rare.

Now I don't know if the problem is still there. If it is (=boiler is heating, despite no heat request from the thermostat), you should try to figure out if the issue is related to the boiler or to tado. The easiest way to do so is to remove the Extension Kit from its backplate. It hinges at the top if I remember correctly. Don't touch the wiring! If the boiler stops heating very rapidly after you physically prevented the Extension Kit from controlling the boiler, then the issue is the Extension Kit. If the boiler continues heating when the EK is not physically connected, then the issue is related to something other than tado. Something related to your boiler, most likely.

Edit:

To remove the EK from its backplate (pictured), you might have to undo 2 screws at the bottom (red circles). You can then remove the EK, it hinges at the top, at the two green circles. I edited out the wiring in this picture with the white box, to not confuse anyone.

You can and should leave the back plate as it is. There will be high voltage on the wiring, so you should not touch that. Removal of the EK from its backplate means that it can in no way control your heating any more. This should help you pinpoint the cause of your problem.