I'm having a strange valve issue in our bedroom. We have 6 valves that have operated perfectly since March. Now that it's getting cold again, the temperature on the bedroom valve is often off somewhere between +2°C and -4°C, leading to room temperatures between 19°C and 25°C when actually it should keep the room at steady 23°C. I tried playing around with True Temperature, but it didn't help.
Now here comes the interesting part: I thought the valve was just broken, so I switched it with a valve from another room. The result was that the "new" valve in the bedroom had the same issues as the old one, and the old one worked fine in the other room. I tried this one more time and switched the bedroom valve with the one in the living room with the same results: For some reason, valves in the bedroom sense a wrong temperature, often staying well below the set temperature and heating the room for hours, and other times just stopping to heat and not turning on thinking the temperature is ok, while the actual temperature of the room becomes way too cold.
To clarify, the temperature sensor on the valve shows a wrong temperature. If I use True Temperature to correct the temperature, it temporarily works again for a few hours until the problems start showing up again. It is not an issue of the thermometer I used to measure the correct temperature, as the difference could be clearly felt (for example, the 19°C instead of the 23°C that the valve showed were obvious when entering the room).
Right now I have taken the valve off the radiator and installed the original low-tech valve which seems to be working fine, but of course it can't tell the thermostat to turn on the boiler when it's cold in the night.
Since the thermometer right next to the radiator measures the temperature correctly, the old low-tech valve works fine, and multiple valves are affected only in this room, I suspect an issue with the firmware. I'm quite tech-savy with experience in coding firmware and soldering, so if there is anything else I can do to try and troubleshoot this issue please let me know.
Additional info that might lead to solving this mistery:
- The valves have firmware 81, the problems started showing up on 4. November after we used the away feature for a few days during which the temperature dropped to 14°C in the flat.
- To switch valves, I uninstalled them via the app, exchanged them and then added them again in the app.
- The radiator is under a window, there are no curtains and no furniture is close to the radiator. The whole room allows for good airflow with the bed in the middle and some closets along the non-exterior walls.
- The size of the bedroom is 17.5m² with a height of 2.5m, with 1 exterior wall and one half-exterior wall, where the adjacent building ends at about 2m height of the room. It's the top-most floor of the building with only the attic on top of it, and very badly isolated with a 30cm thick exterior wall and no thermal insulation whatsoever due to the age of the building. The radiator is 1.6m wide.