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HmIP-eTRV-B actuator constantly overshooting given setpoint

Verfasst: 09.12.2019, 10:27
von Inquirer8087
Hey guys, i'm having some very strange problems with my eTRV-B's. Got them a month and a half ago from cyberport (HmIP-SK9) an it seems that they are constantly overshooting the set point by 2-2.5 degrees when the boiler turns on.
trend (1).png
I've hoped that the actuator would settle in time but it's not happening. The same pattern for a month now. Checked everything, reinstalled the trv, redone the adaptation run, verified that it cuts the flow to the radiator at 0% level ... nothing helps. The only solution I've found whas to specify a 2 degree lower set-point. If i pair the eTRV-B with a WTH-2 it's tracking just fine. Could it be a firmware bug? Right now i'm on firmware version 1.0.20 and there is no new firmware available. I've still got some old FHT8v's paired with a FHT80b and those are tracking just fine. I'm using a ccu charlie with latest firmware.

Re: HmIP-eTRV-B actuator constantly overshooting given setpoint

Verfasst: 09.12.2019, 13:28
von tomi_cc16
Hi,

Welcome in the english section. Where you from and found out about Homematic IP.

Im not 100% understand your diagram. (Is it from the WTH-2 or eTRV, multiple devices??)
How did you all connect them, did you put all in a group?
If not yet, try it out.

Data that you could track not sure if its in your diagram.
1. Measured real temperature at WTH-2 (Actual)
2. Set Point temperature at WTH-2 and eTRV
3. Measured real temperature at eTRV (Actual)
4. Valve Position (Level) of every single eTRV‘s

Do I understand correctly that Set temperature at WTH-2 (Master) is reached but valve of eTRVs are not closing enough to keep the temperature so the rooms heats up more than you want?

Re: HmIP-eTRV-B actuator constantly overshooting given setpoint

Verfasst: 09.12.2019, 13:56
von Inquirer8087
Inquirer8087 hat geschrieben:
09.12.2019, 10:27
Do I understand correctly that Set temperature is reached but valve of eTRVs are not closing enough to keep the temperature so the rooms heats up more than you want?
That is correct. The complete description would be that the eTRV valve is opening even if the setpoint temperature is already at or over the desired level (20,5 celsius in my example). After the temperature reaches 22,5 celsius it regulates the valve to maintain that temperature. For example in the attached graph at 5:30 the setpoint changes from 18 to 20,5 with an actual temperature measured of 20,5 (top graph). Instantly the valve opens to 34% and heats the room to 22,5 celsius.
Inquirer8087 hat geschrieben:
09.12.2019, 10:27
1. Measured real temperature at WTH-2 (Actual)
2. Set Point temperature at WTH-2 and eTRV
3. Measured real temperature at eTRV (Actual)
4. Valve Position (Level) of every single eTRV‘s
1. I don't use a WHT-2 in this room just a single eTRV-B
2. see 1.
3. see 1.
4. blue graph in the middle (multiply by 100 and you get eTRV valve %)

LE:
I've been using homematic in one form or another from 2012. Started with used ebay FHT components from ebay. Later i've added a CCU2 and now i'm in the process of adding some IP components. Right now i'm using a combination of FS20 FHT and IP on a CCU Charlie with a CUxD addon.

Re: HmIP-eTRV-B actuator constantly overshooting given setpoint

Verfasst: 09.12.2019, 14:01
von Sergo
Inquirer8087 hat geschrieben:
09.12.2019, 10:27
Hey guys, i'm having some very strange problems with my eTRV-B's. Got them a month and a half ago from cyberport (HmIP-SK9) an it seems that they are constantly overshooting the set point by 2-2.5 degrees when the boiler turns on.
.... If i pair the eTRV-B with a WTH-2 it's tracking just fine.
I have seen exactly same behavior year ago with eTRV's that run "alone", connected directly to CCU, without WTH-2. Replaced one of the eTRV's - no change. Then moved same to another room - it works fine.
So, my conclusion: there is some specifics in behavior of eTRV + exact location in the house that result in such behavior.
Current solution: avoid "eTRV Alone setup" or count for shift of temperature reading

Re: HmIP-eTRV-B actuator constantly overshooting given setpoint

Verfasst: 09.12.2019, 14:23
von tomi_cc16
Sergo is 100% correct, eTRVs alone in most cases don’t work well. WTH helps to control the situation.
What you can do and already did is to play with the offset - but the results will be always mixed.

See my answers also here:
viewtopic.php?f=49&t=54669

Where you from?

Re: HmIP-eTRV-B actuator constantly overshooting given setpoint

Verfasst: 09.12.2019, 14:30
von Inquirer8087
Damn, pretty old bug! I think i'll stick with the 2 degree lower setpoint. Buying a WTH-2 to control a single radiator doesn't make sense. Does eQ3 has a bug report form or something?

Re: HmIP-eTRV-B actuator constantly overshooting given setpoint

Verfasst: 09.12.2019, 14:32
von tomi_cc16
Inquirer8087 hat geschrieben:
09.12.2019, 14:30
Damn, pretty old bug! I think i'll stick with the 2 degree lower setpoint. Buying a WTH-2 to control a single radiator doesn't make sense. Does eQ3 has a bug report form or something?
I personally don’t think its a bug but difficult to achieve with your circumstances only using eTRV and without WTH. Here the eQ3 contact.
contact eQ3: support@eq-3.de
https://www.eq-3.com/service/support.html

Where you from?

Re: HmIP-eTRV-B actuator constantly overshooting given setpoint

Verfasst: 09.12.2019, 15:25
von Sergo
Inquirer8087 hat geschrieben:
09.12.2019, 14:30
Damn, pretty old bug! I think i'll stick with the 2 degree lower setpoint. Buying a WTH-2 to control a single radiator doesn't make sense.
I got to the same conclusion... :wink:

Re: HmIP-eTRV-B actuator constantly overshooting given setpoint

Verfasst: 09.12.2019, 19:01
von Inquirer8087
I personally don’t think its a bug but difficult to achieve with your circumstances only using eTRV and without WTH. Here the eQ3 contact.
contact eQ3: support@eq-3.de
https://www.eq-3.com/service/support.html

Where you from?
From Romania, Bucharest. The homematic system is not very well known here (besides, every component is obscenely expensive). Everybody just installs a simple wireless room thermostat to control the boiler and classical radiator valves to regulate every room.

As for your suggestion that my particular circumstances are bad or not ideally suited to just an eTRV install and I should be better served by a WTH allow me to strongly disagree. As per eq-3 description the eTRV is marketed as a standalone component and it should regulate the temperature as good as the WTH-2. Nowhere on the box, or in any official documentation doesn't state that I have to buy a WTH-2 otherwise the temperature regulated by the TRV would be off by a few degrees. It's a textbook bug. As per eq-3 examples the WTH-2 is useful when controlling multiple TRV's in the same room or for controlling underfloor heating. A WTH-2 controlling a single eTRV in the same room is nonsense imo.

Re: HmIP-eTRV-B actuator constantly overshooting given setpoint

Verfasst: 09.12.2019, 22:27
von tomi_cc16
I understand your point - but my personal opinion and experience is different. I have 4x rooms always with just 1x eTRV + 1x WTH.

And only one room with 1x WTH and 2x eTRV.

My guest toilet I have only an eTRV and there I keep the temperature constant on 18 degrees.