Sonoff TRVZB calibration is lost

[il0]

Hey, and thanks for this fantastic add-on!

I’m using VTherm with the SONOFF TRVZB, and in rooms with an external temperature sensor, it works great—significantly reducing valve movements compared to other thermostat implementations.

However, in rooms without an external sensor, VTherm behaves unpredictably. Initially, it seemed to work, but after a few days, the temperature offset drifted to -12℃, causing excessive heating. I’m unsure what the best settings are for VTherm in situations where no external sensor is available. Should temperature offset be used at all?

Since VTherm requires a Room temperature sensor entity ID, I had to create a helper using the TRVZB’s built-in sensor. However, this creates confusion regarding the Use underlying temperature option—since both the internal sensor and the room temperature sensor are the same, it’s unclear whether this setting should be enabled.

Would it be possible to improve clarity by moving the Use underlying temperature checkbox to the main configuration page? Selecting it could then make the Room temperature sensor entity ID optional, simplifying setup for users without an external sensor.

Thanks again for your work!

[jmcollin78]

Hello, I think ypu run into the "calibration issue" of Sonoff TRVZB. If the regulation threshold is too low, the Sonoff TRVB can need some recalibration.

If I understand, you should remove the battery and redo the initial procedure. There is a post on this subject on the issue or discussions.
Then set this regulation threshold to 5 (and not 0.05 which is for °C regulation. The documentation is not clear and I have to improve that particular point.

[il0]

Thanks for the answer! I will try this. Two questions that are still unclear:

• Should I use the Use underlying temperature option?
• Should I add the "Offset calibration entity" to the valve regulation control or not?

[jmcollin78]

Should I use the Use underlying temperature option?

Never !

Should I add the "Offset calibration entity" to the valve regulation control or not?

Always !

[ishbuggy]

Is it still recommended to change the regulation threshold to 5 with a TRVZB? It was working fine for days, but all of a sudden I found last night my TRV set to be idle for hours, but was actually still heating and the temperature got very high. The valve percentage was supposed to be 0%. Could this be the problem? It is difficult to figure out what went wrong.

[il0]

I can report now after 1.5 weeks of testing, that having the regulation threshold at 5 removed the calibration issue. There was no need to take off batteries, just change the threshold.