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Valves - epic fail !

Posted: 14 Dec 2017, 22:36
by mdillmann
tonight my boiler (not regulated by Thermostat) got into an error condition so rooms where quite chilly when I got up late this morning. I then quickly heated via wood-oven before fixing the boiler.
Screenshot-2017-12-14 Netatmo(1).png
So one can see that temp - as measured by valve - got stuck around 18 degrees from about 12.00 until now (22.00) where it reached 19. Right now it is heating at 100% trying to reach 21 degrees, while we are already at 23.7 per Station. Valve "computes" the room-temperature at 19.7 currently :?:

The REAL temp is quite different:
Screenshot-2017-12-14 quellenweg.png
There we are at about 22 degrees.

I lowered thru the manual boost the target temperature because I wanted to avoid what is happening right now: because the valves only measure about 19 degree where it is in reality 22,23 they start opening up and overheating the room to now almost 24 degrees !
Besides the total waste of energy this is simply not healthy.

Apparently "the algorithm" that computes the "measured" temperature completely sucks. It seems to work "ok", when the radiator actually heats and thus heats up the valve socket. But it fails miserably when the radiator is not needed to provide heat and the valve-socket is "cold" (technically in this case it would be easy to just use the measurement of the outer sensor without alteration).
What makes things even worse is, once the radiator supplies heat "the algorithm" is way to slow to react to reflect the real room temperature.
Interestingly a "calibrate" fixes things. But I did not buy these valves to always keep an eye on them if they regulate correctly and then fix things by applying a manual "calibrate".

So Netatmo here is my request: get a life. Get rid of those fancy, "learning, self, adjust" stuff and get your homework done. Get the basics right, like quick measurement of real room temperature under normal living conditions. If that works, you can try play with the fancy stuff and reach the promised energy savings.


Re: Valves - epic fail !

Posted: 14 Dec 2017, 22:53
by mdillmann
Even worse in the bathroom.
Screenshot-2017-12-14 Netatmo(2).png
When the boiler came up again around 11, the valve measured about 19 degrees. It keeps this through the day, demanding "full power" heating all the time. The temperature was about 21 around 15.00 and just reached 22 degrees at 22.30.

Now the REAL values as measured with Station:
Screenshot-2017-12-14 quellenweg(1).png
Currently we are heated up to 25 (!) degrees. I accept an offset of about 0.5 to 1 degree as tolerance, but just compare the steepness of the curves. Even in the heating condition (that radiator was not set to "manual boost" and thus did not get cold) the computation of the room-temperature does not work.

@Brieuc: any ideas ?

Re: Valves - epic fail !

Posted: 15 Dec 2017, 23:53
by risodv
mine bedroom valve react same way. From 16..19 degrees is almost as indoor module but in higher tempetatures difference is much bigger. When indoor module shows 21.6 degrees, valve shows only 19.5. Valve has big hysteresis comparing to indoor module.
I do not understand how they (netatmo) can detect if window was opened because valve will notice it after twenty minutes.
It looks like total failure to correctly measure temperature with valves and do correct heating regulation without wasting our money. I am realy disapointed.