Support for the new SONOFF TRV Gen2?

[ishbuggy]

Has anyone had a chance to test VTherm with the new Sonoff TRV Gen2?

[bontiv]

Hello! I don't have the gen2 of Sonoff TRV but it should work fine. The new version is supported by Zigbee2MQTT.

According to the documentation, the new hardware exposes two valve-position values:

• heating_valve_position
• idle_valve_position

You could add both exposed valve-position values as valve-opening entities in the VTherm configuration. That should work fine. If you can test this, I'll document it on the VTherm website.

[bontiv]

Can you try this as workaround : https://www.versatile-thermostat.org/en/devices/sonoff-trv-zbt/

[Stepyon]

@bontiv I also noticed that changing "heating_valve_position" and "idle_valve_position" is not enough to open the valve if the setpoint is close to the actual temperature. The valve is still controlled by internal thermostat, so it counts the local setpoint vs current temperature and also taking into account "temperature accuracy" value. It is very often when I see the both valve positions set positive but the valve stays closed, here is a state example:

"heating_valve_position": 64,
"idle_valve_position": 63,
"occupied_heating_setpoint": 22,
"local_temperature": 21.7,
"temperature_accuracy": -0.4,
"running_state": "idle", // (the valve stays closed when idle)

So in this case it will open only if temperature drops to 21.4 or less (setpoint - temperature_accuracy) and it doesn't matter what VTherm wants. The value of "temperature_accuracy" can be changed from "-1" to "-0.2" but still it doesn't help to sync it to VTherm much.

It looks like if the valve is "idle" changing the "idle_valve_position" from "0" to a positive value doesn't trigger the valve openning.
But if the valve is "idle" changing the "idle_valve_position" from a positive value to "0" does trigger the valve closing.

In my understanding if VTherm wants to open the valve it should:

1. Set both "heating_valve_position" and "idle_valve_position" above "0".
2. Increase the valve "occupied_heating_setpoint" above VTherm's setpoint (and local temperature) for a few degrees OR decrease the valve's "local_temperature" (fake it) below the real temperature for a few degrees.

[bontiv]

Is your smart_temperature_control disabled on your configuration?

If I understand, when the TRV is idle, it should use idle_valve_position but changing this attribut do not trigger the motor in either direction. Only closing direction. This looks like a firmware bug from Sonoff...

[gregorko]

I also noticed the behavior @Stepyon described, but did not dive so deep into it.
The TRV seems lazy and delayed triggering the motor, the temperature_accuracy seems to be related but I couldn't find a consistent way to reproduce or force trigger the motor.
I use ZHA and I think smart_temperature_control is called adaptive mode there. I have it off.
Before I found this thread I also came up with similar finding as described by Stepyon at the beginning of the thread. I also implemented a similar script to sync idle and heating value position. My script set both values equal, not the idle lower then heating logic. Seems to also work fine for me. But the -1 logic sound more correct.

[Stepyon]

I just tried to move "Idle valve position" slider manually while the valve is in idle state - no reaction at all, in both ways: "0" -> "100" and "100" -> "0", the motor is not spinning.
It works properly only in "heating" state, which depends on this condition:
"local_temperature" < ("occupied_heating_setpoint" + "temperature_accuracy")

I have "Smart temperature control" OFF.
I also have the most recent firmware (4352) available on Zigbee2MQTT.

P.S. Maybe we should report a firmware bug on Sonoff forum if more people can reproduce and confirm the issue I see.