Tado constantly firing boiler

Eddyrz

so my smart thermostat is set to heat at 15.2 but for the last week the boiler seems to just be constantly on the thermostat now reads 23.2 and its still on. i have checked this against a thermometer in the same room and its reading the same. i have had the tado for over 4 years but now its just started doing this. any ideas?

Zenblg

Same problem here. Tado smart thermostat keeps heating even after reaching the target temperature of 18°C. Now the temperature in my house is close to 25°C and the only fix is to manually close the valves of all the radiators. Very annoying!

royi

@Eddyrz and @Zenblg could you both upload a picture of the heating graphs, so that we have a more understanding of how your system is set up and provide you both with an answer.

Zenblg

Hi @royi,

It seems all my heating graphs of 2023 have been deleted. I could visualize them yesterday (31 Dec 2023) but not today. I could only visualize today's heating graph.

You can see the temperature decreasing from 25C to about 21C as a consequence of my closing the valves of all radiators but one. Below you can see my schedule (always worked fine, never had an overheating problem) and the home screen snapshot.

Eddyrz

Mine is similar to zenblg set to 18 now at 28 just doesn’t seam to turn the boiler off, Iv tried reseting the bridge pulling it out the router but it’s not done anything

wateroakley

@Eddyrz & @Zenblg While it may or may not be a tado problem, have you checked if a zone valve has failed or is stuck ? The zone valve is a most likely suspect; i've seen them fail anytime from a few weeks to 20 years.

In a Y-PLan or S-Plan system, Tado controls the zone valve, not the boiler. Tado tells the motor in the zone valve to move and 'open' the valve. When the valve is 'open', the internal switch will close, which activates the boiler. Where the valve is siezed 'open', the boiler will keep going 24x7. If the valve does not fully open, the switch may not activate the boiler. Faulty Mid-position valves (Y-Plan) can make the boiler appear to do strange things.

To check what is happening: There should be a manual lever on the side of the zone valve; e.g. below. Move the lever to the right, When Tado is 'off', the valve should be closed and the lever should offer spring-loaded resistance. When Tado is 'on'. the valve is 'open' and the lever should offer little resistance. It should also be possible to latch the lever in the manual 'open' position.

Eddyrz

So I managed to fix it all I did was turn the zone controller off for a night and now it seams to be working as normal again