@Alexie FYI: setting the calibration in iHost is giving some issues… if i set the calibration to 3 C then temp is calculated correctly (18 instead of 15 for instance) but if then choose 4 C for calibration the temp goes from 15 tot 32 degrees.
Using the API i am able to update the value correctly using the same body as iHost does
Wanting a feature that is not common on Zigbee valves in anything like this price range to be added in preference to basic functionality of being able to see and manipulate a valve at all with a phone is just silly.
This is what i mean… you are calling my opinion silly, and i do not appreciate that at all.
And to be perfectly honest… the absolute basic function of a TRV in general is to keep the temperature of the room consistent… i suggest you read up on it before calling my suggestion silly:
The valve gradually closes as the temperature of the surrounding area increases, limiting the amount of hot water entering the radiator
If they then go and make it smart, wifi connected or whatever then it should keep the basic thing available what it is designed for. And me asking for this feature and personally seeing at as more important does not make me or it silly.
European smart thermostats are chronological, they anticipate the heat rise and fall of a room giving a much more level room temperature. The problem with all of the Sonoff thermostats and equivalents is they are dumb inaccurate thermostats. They are by far the worst I have ever used (I am a heating engineer). Just because they are connected to the internet doesn’t make them smart
TRVZBs and room temperature sensors show different temperatures. In this case, how do I adjust the temperature of the room? Since TRVZBs are next to the heat source, the temperature they display is not the temperature of the room, making it not possible to adjust the room temperature via TRVZBs. I’m tired of constantly calibrating TRVZBs. TRVZBs have to get temperature information from the temperature sensor in the room. In its current form, TRVZBs are just a device that you can manually turn on and off.
I think I understand your point, I was also “surprised” at the beginning when I realized that my TRVZB was working “All_Open/All_Closed” and had no middle points.
Later, after “thinking” what would be needed for having middle points (from a hardware perspective) and what extra benefits it would give, I think I understand why they didn’t implement it. The middle points would need some sort of feedback of the position, which is not that easy to do (from a cost point of view), while the benefit will be just “smoothing” the change in the flow of water, not necessarily on the temperature of the radiator itself, which already has some smoothing due to the slow reaction and heat transfer, and less effect in the whole room itself. Actually, for the whole room it might be even better to have a “faster reacting” radiator.
I believe the main problem of this valves is using a temperature probe that is so close to the radiator itself. That was a necessity before “smart interconnected TRVs”, but is not anymore, it should be possible to couple the control of the Valve to a different (better positioned) temperature sensor.
The valve does adjust itself when installing/callibrating to make sure the open/close position is correct so you would think that at that moment a start and end point is known giving the option to get an % in between open and close.
@FedericoDC it is currently not directly possible (when i last checked) to link an actual sensor but scene can be made using a different sensor and i’ve noticed that if you calibrate the temp of the device to somewhat match the temp of the other temperature it does seem to be working better. This does however not compensate for the fact that it is only on and off
@Alexie mentioned an update in march but i do not know the exact updates
I suspect it is just looking for the endpoints, based on the motor current (and accepting a very short blockage of the motor when it reaches one of the ends…) similar to when a DualR3 used for blinds is calibrated… In that case, however, there is the possibility of reaching intermediate positions since the AC motors used in this blinds (not provided by sonoff) have almost stable velocities in the whole range of movement, so the “position feedback” comes from the time since starting the motor, and doesn’t really need to be too accurate (when I send my blinds to 75%, is is actually more like 60% ) In the case of the TRV, they are using a DC motor powered by three AAA Batteries in a short movement span. I don’t expect that velocity to be stable over the life of the batteries…
An, then again, I don’t think the benefit would actually be what we “would want”. Imagine filling a “big bucket” with water from a “small hose”, with two options: a valve that goes on an the press of a button, or a valve that you can regulate. Both supply very little water. When the bucket is completely empty, you open both valves completely, so both work the same. When you are just recovering for the evaporation losses, in theory the “controllable valve” would be better, you could calibrate it “exactly” for the amount of evaporation due to the exact temperature and humidity of the room… But the fact is that those variables WILL change during the day, so you would need to keep regulating that valve and find a complex mathematical equation that somehow “predicts” the position in which the valve needs to be in the next moment. That is what “control loops” try to do, usually with three parameters (p, i, d).
In the case of the “a lot simpler” on/off valve, you will press the button until you reach the level you want, maybe a little more (hysteresis) then leave it off for a while and then check the level again. Your only calibration parameter is “how much you overshoot”. Of course this is not perfect, of course the other valve will have a more stable water level, but, will it be worth it? Depends on the size of the bucket and its comparison to this “level difference”. Just the same with the TRV, it actually depends on the size of the room and the time it takes for the Radiator to heat it, also the size of the radiator itself, given that the valves seam to be the same size for different radiators. A very small room with a very small radiator might benefit from the valve with position control. A bigger room, I don’t think so…
Anyway, I am not sonoff’s lawyer, they decided to do it on/off, I just share my thoughts on why I think they did it
I stopped worrying about the TRV’s temperature, I just replaced the thermostat of my heater with the “next model of the same manufacturer”, second hand from ebay (cheaper than the TRV) and this new model has a temperature display which shows almost the same temperature as the sonoff termometer underneath it (that will therefore soon be used for something else). So, I put the temperature of the TRV one degree higher and it is the heater thermostat the one controlling the room. Sometimes I see in the ewelink the TRV is in “heating” status, at 15°C, since the room itself is at the expected temperature and the TRV is under a window. I don’t have any remote control of the setup temperature, my plans were to use the electronics of the original thermostat in order to build one with an esp32 or something, I don’t know if I will ever do it…
So, basically, the TRV become superflous at that radiator, someday I will put it somewhere else (by the way, the installation manual of my heating system says that the radiator in the same room as the thermostat should NOT have a thermostatic valve… But I think that the non-thermostatic valves where forbidden in Germany a few years ago, I cannot find them anywhere…)
) In the case of the TRV, they are using a DC motor powered by three AAA Batteries in a short movement span. I don’t expect that velocity to be stable over the life of the batteries…