Oscillations on the temperature graph

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FabioPA
Posts: 4
Joined: 22 Dec 2018, 14:27

Oscillations on the temperature graph

Post by FabioPA » 22 Dec 2018, 14:42

Schermata 2018-12-22 alle 14.24.51.png
Good morning, this is my first post and I take this opportunity to greet you all.
My question is about the graph of this valve. I wanted to know if the oscillating temperature is normal. I have also tried to replace the valve, but the oscillation is repeated on the same radiator.
I noticed that on other valves the graph is much more linear.
I have read that the Netatmo valves have two temperature sensors but I do not know where they are positioned.
The oscillation could depend on the presence of a reinforced concrete column immediately to the right of the valve?
Thank you very much and Merry Christmas to all

Gresteh
Posts: 11
Joined: 24 Dec 2018, 12:18

Re: Oscillations on the temperature graph

Post by Gresteh » 24 Dec 2018, 12:44

Yes, that's the normal behavior of a valve. You must keep in mind that your valve will only request heat once it's below its target temperature, until then your valve will remain closed and will not request heat. Once the valve senses that the room is below your target temperature will request heat, that will cause the temperature to rise again. Another thing you have to keep in mind is the thermal inertia of your room, it takes some time to heat your room and your room takes some time to cool down. It’s not immediate and will cause those oscillations. Your valve may only show increments of .5 degrees, but it can measure and report smaller increments, and that’s what you are seeing, after the valve closes the room will get a few tenths of a degree hotter than your goal and once it begins heating again will still cool down a few tenths of a degree until your radiator overcomes your room’s thermal inertia.

mhaga
Posts: 48
Joined: 07 Dec 2017, 10:08

Re: Oscillations on the temperature graph

Post by mhaga » 25 Dec 2018, 17:10

Hi,
Have observed the same behaviour on my system. I don't think the valve thermostats have proper PID regulation, only the boiler thermostat. This is only my thoughts, but I think a closed loop PID regulation, will have av very different regulation curve. The overshoot should be smaler and smaler for every iteration and in the end the temperature will be very stable and the valve should have a close to constant but small opening, dependent of your house/apartments thermal characteristics. Not sure if this is possible to achieve in heating systems for houses and apartments, as there are many variables that can change. In my apartment the temperature are regulated within +-0,5 degrees of the configured temperature, so I don't worry that much about it. The temperature I see/are measured on the valve thermostat itself, have more variation than the actual room temperature.

BR
/mhaga

FabioPA
Posts: 4
Joined: 22 Dec 2018, 14:27

Re: Oscillations on the temperature graph

Post by FabioPA » 25 Dec 2018, 23:05

That's exactly what I noticed.
The valve sensor is too close to the radiator.
The temperature fluctuations are too large compared to the real ones measured on a room thermostat.
I believe that to be perfect, the netatmo system would need small temperature sensors to be included in the rooms.

frykvall
Posts: 8
Joined: 29 Nov 2018, 08:39

Re: Oscillations on the temperature graph

Post by frykvall » 28 Dec 2018, 09:02

I have observed the same thing and the Netatmo support are pretty much no help at all. Before my Netatmo valves I had Danfoss Living Eco valves and they where pretty much spot on the whole time with no fluctuations in temperature. But if I use my Netatmo valves and then check the temperature with an external sensor I see the same result as you.

max@mo
Posts: 7
Joined: 15 Dec 2017, 09:00

Re: Oscillations on the temperature graph

Post by max@mo » 07 Jan 2019, 12:02

FabioPA wrote: The temperature fluctuations are too large compared to the real ones measured on a room thermostat.
Same behavior here but just on the last added one of the two valve in my system. The oldest one is in place since the 2017 end and it doesn't show any weird fluctuations and surely the temperature showed are more in line with the whole room temperature.

mhaga
Posts: 48
Joined: 07 Dec 2017, 10:08

Re: Oscillations on the temperature graph

Post by mhaga » 08 Jan 2019, 17:22

Hi,
Have you people worked the "true temperature" parameter under settings for each valve thermostat? It is under "Manage my home"
I have mixed results form manipulating it, but for small rooms it works well.Have to use external thermometer in addition.
BR
/mhaga

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