Heating on even though over target temp

flimble

Over the last couple of weeks our heating has been staying on even though the room temperature is over the temperature the thermostat is set to.

As I write, the thermostat is showing 19.4 and, according to the tile in the app, Tado is "heating to 19.2".

I'm not a physicist but even so, I believe it will have a hard time achieving its goal.

GrilledCheese2

The text "Heating to" does not necessarily mean the boiler is on. It means the Tado thermostat is actively controlling the room temperature. This is normal behaviour for a time proportional integral (TPI) thermostat.

Assuming you previously had a traditional thermostat which will always switch off the boiler when the target temperature is reached. Then the room temperature drops by at least 0.5°C (hysteresis) and switches the boiler back on.

Whereas a TPI thermostat learns how a room heats and calculates how long a boiler needs to on to maintain a set temperature. It might decide the boiler needs to be on 25% of the time, which means the boiler is on for 15 minutes in each hour. The thermostat will periodically switch the boiler on/off to achieve the necessary amount of heat input to the room. After any initial overshoot in temperature your thermostat should maintain a fairly constant temperature.

flimble

Thanks. For what it's worth, the boiler definitely was on.

I'm going to leave it next time, and wait to see how long it takes to switch off (assuming it does)

paulnoble_1

I was just coming to post a query around that and ours is doing the same, all rooms are way over target and the boiler is definitely active, but the app shows that no rooms are calling for heat.

is there any "event" logs on the system that would allow us to pin down which device the tado thinks it's heating? (Or also show if it initiated an 'off' to the boiler which its then ignoring).

paulnoble_1

As a follow up to this, somewhat prophetically, the tado system reported shortly after posting the above. This is a common theme, it seems the entire system gets upset just before it reports errors.

the error highlights other problems in the bridge/web app behaviour. What I see happening is this:

1. the system starts over heating all rads as if something calling for heat, no errors on web app, website or wireless controller.
2. the wireless controller reports an ! But the app has no error listed
3. the web app reports an alert on the rooms and devices, but rooms and devices listing shows no errors on any room
4. the room device finally alerts there is a problem, either an undisclosed error, or a connection error
5. i get an email alert some hours after the stage 2 saying a rad trv battery needs replacing.
6. replace the batteries and the whole step process reverses.
7. occassionally I'll have the devices have good status on the device but list an error in the device and rooms listing, massively confusing.

now all of that is ok if it occurred quickly, but it doesn't, each of these stages can take hours to traverse, from stage 1 where there are no alerts but the system is just burning gas to 5 this can take upwards of 2 days, meaning a lot of cash wasted on needlessly over heating the house because it can't report faster.

I'm getting to the point where if it starts into stage 1 I just shut down all boiler control until it figures it's stuff out and emails me. But really, it should be telling us immediately and reliably from the app what's going on rather than relying on an email notification to tell me something the app should list front and centre, especially when the result is for it to burn your cash for nothing.

AzertyNL

I'm in the same boat as well.

My typical scenario is:

My tado room thermostat calls for heat as it should, the room slowly warms up (it takes 1 hour per degree due to UFH), an hour or so later the set temperature is reached.

At this point I would expect the room thermostat to stop calling for heat as the room will continue to climb in temperature for another half hour anyway due to UFH being slow at releasing the stored heat. So the temperature keeps rising and overshoots the set target by +0.5 degrees usually. (It takes over 3 hours!!! to lose this +0.5 degree overshoot if the boiler would not burn at all in my home when the outdoor temparature is about 15 degrees lower)

Yet, during the overshoot period, i still see that the thermostat will actually call for more heat, by observing the boiler itself, the burner comes on periodically and my gas meter data proves the consumption at the point in time (after the set point has been reached for quite some time). (I've made sure the boiler is not coming on for warm tap-water...)

I was very surprised and disappointed by this, I'm not sure if need to be more patient for the tado to learn my systems properties, I have it running for 3 weeks now) or that I have unrealistic expectations but my previous honeywell chronotherm IV learning thermostat nailed the job for 20+ years until I replaced it 3 weeks ago. (unhappy face)