Hi, I have the following Bosch devices configured in my living room:
- Smart Home Controller II
- Raumthermostat II
- 2 x Heizkörper-Thermostat II (I have two radiators in my living room)
They are all using the latest firmware, and all configured correctly with the Smart Home app on my phone.
I set the "warm phase" temperature to 23° and configured the schedule to begin the warm phase at 7:00 in the morning each day. Then I wake up at 8:00.
However, I have discovered that the thermostat never seems to stay at 23°. It is always either more than 1° above or 1° below the target temperature.
For example, when I wake up at 8:00, the room thermostat shows that the actual temperature is 24° or even higher. It seems that the radiator thermostats have opened their valves to 100% for too long, and this resulted in the temperature increasing beyond the target 23°.
I've attached a screenshot to show this. You can see from my screenshot that the target temperature is 23° but the actual temperature is 24.3° which is too hot.
Then the radiator thermostats close their valves to 0% and the room slowly cools down, but now the temperature drops down to 22° or lower - so now I feel it's not warm enough.
Then it repeats: the valves are opened again to 100%, and the temperature jumps up to 24° or more. So throughout the day, the temperature is jumping up and down beween 21.x and 24.x but never sitting stable at 23°. Therefore I feel either too hot or too cold in my apartment. (My body is very sensitive to the fluctuations in the temperature).
It would be nice if the radiator thermostats would start to close their valves *before* reaching the target temperature, so that the target temperature would not be overtaken, and then the thermostats should keep their valves open at a small amount (maybe 20%) to maintain a constant and stable temperature throughout the day.
When I used the original, mechanical thermostats that were attached to my radiators, I could set them to a certain position in the morning, and they would maintain a constant and stable temperature throughout the day. I would like the Bosch thermostats to function the same way.
I've seen some other posts in this forum from other users with the same problem, so it seems that this is a known issue. For the record, a couple of months ago I had the original Smart Home Controller (not the new model) and it had the same problem - in the end, I sent it back to Amazon for a refund. I hoped the new Smart Home Controller II would be better, but it seems not.
One other note: before I purchased the Bosch Smart Home devices, I tried the smart thermostats from Homematic IP. In the end, I sent them back to Amazon for a refund, because I didn't like the way they worked. However, one feature that I liked about the Homematic IP thermostats, is that they did maintain a stable and constant temperature throughout the day. And their app also has a feature called "Optimum start/stop function", which allows the thermostat to calculate the required lead time in advance, to slowly close the valve before passing the target temperature. I've attached a screenshot here of this feature. I think it would be helpful if Bosch can introduce something similar, to help prevent the thermostat from allowing the temperature to go above and below the target temperature throughout the day.
In any case, if my mechanical thermostats can maintain a stable temperature, and if the Homematic IP thermostats can maintain a stable temperature, then I see no reason that the Bosch thermostats should have this problem.
