Question about Sonoff TRV control

[dantrio]

Have a quick question about the behaviour of the Sonoff TRV when setup using direct valve control. All seems to be working well in that versatile thermostat is controling the valve open degree on the origional sonoff trv device in home assistant, and controlling the temperature via a seperate temperature sensor, but it seems like the TRV does not react to when versatile thermostat tells it to heat.

For example the current set point in VT is 17c, the temperature reported by the thermometer and showing in VT is 16.8c and the VT is showng as heating at 19% power, and when i look at the origional sonoff device it shows the valve open degree as 19, but the climate state is idle. The temperature is showing correctly as 16.8c but is not taking the heat command from VT and as i understand it the open valve degree is set correctly but as the TRV is still in an idle state the valve is closed. It seems that only when it drops to around a degree off of the set point does the valve change to heating mode regardless of when VT is showing as heating. Is there a way to change this behaviour or is this just a limitation of the sonoff TRV? Currently there can be quite a big swing in temperature as it seems to wait quite a while before turning on when cooling down, and currently seems to be over heating by about a degree as well but im sure this can be tuned by adjusting the tpi parameters

[jmcollin78]

The temperature is showing correctly as 16.8c but is not taking the heat command from VT and as i understand it the open valve degree is set correctly but as the TRV is still in an idle state the valve is closed.

Hello, I think you ran into this bug (see the note at the end):
https://github.com/jmcollin78/versatile_thermostat/blob/main/documentation/en/self-regulation.md#self-regulation-by-direct-valve-control

Note: for Sonoff TRVZB you should not configure the "closing degree" parameter. This leads to a bug in the TRV and the hvac_action is no more working.

[jmcollin78]

The last thing you can check is that the calibration offset works. Vtherm will change it regularly, you should see it changing over time.

[dantrio]

Hi yes can see this change on the original sonoff device to keep its temperature in line with the temperature from the sensor being used in the room.

[jmcollin78]

So, all is fine then.

[dantrio]

Well the sonoff does take its heat command from versatile thermostat as i said and temps fluctuate about 1.5 c above and below setpoint but apart from that I guess all is fine. I wouldn't worry about it have bought a proper drayton weiser system now and I guess vt works fine for other people so may just be my setup at home or the sonoff trvs just don't play nice with versatile thermostat

[jmcollin78]

temps fluctuate about 1.5 c above

You can reduce the coef-int of the TPI algorithm.

[b4rRa]

Hi :) I will enter this thread because I have same behaviour.

Looks like the Sonoff TRVZB is going to idle about ~0.5°C before Target Temperature, while in VT the Thermostat still shows "heating" with about 27% power.

Everything is configured as should. Temp Offset is working fine as I can see in Z2M. Valve Opening degree works too. Here you can see its 27% while closing is correctly at 100%. But Running State is on idle - so its not heating anymore!

Valve Closing is NOT set in the Config due the bug. Regulation Treshold is set to 3 - Dont know what to do?