Sonoff TRV controlled by Sonoff temperature sensor

[jensolsson]

I control two TRVs from Sonoff by a temperature sensor from Sonoff. It seem to work sometimes but then suddenly hesting turns off even though temperwture has not yet reached correct level.

Also seem to go up and down a lot. See my screenshot.
shouldnt it work with sonoff?

[MrUhu]

Only because you use Sonoff Temperature Sensors and TRVs it would'nt automatically "just work". For that you would need to buy a sonoff bridge - most likely the implementation by Sonoff on their bridges should be working.

Better Thermostat is a solution for Home Assistant to have an "intelligent thermostat". It has nothing to do with the brand you bought. The Sensors are only providing data so that this implementation can do it's thing.

Because your screenshot is not working I would recommend fixing this and maybe share the configuration of the mentioned TRV.

[jensolsson]

Thanks for the reply @MrUhu
The brand might be irrelevant but i have set the temperature sensor and trv in betrer thermostat using Offset Based calibration. It works faily well but it seem that the TRV shuts down the heating using its internal temperature sensor even thiugh the external one did not reach the setpoint.
i have now switched to Target Temperature Based calibration. Seem to work better but downside is that all valves shows incorrect set temperature and i guess it is no longer possible to set temperature on the valve itself.

I think the Sonoff TRV should support offset based calibration?

[MrUhu]

Yes, it does support Offset Based Calibration.

Because of your feeling that it shuts on internal temperature I suggest you add your configuration to this issue, so that one could see if there is an issue.

[folfy]

If you use ZHA, the local calibration parameter of your TRV is probably limited to +/-2.5°C (under Z2M these limits seem to be higher), in which case there's only so much BT can do. If the required difference is bigger, our hands are tied.

You can check the device page and look for the local calibration or temperature offset attribute of your TRV, and see how far the slider goes. If you use ZHA and it's 2.5°C, that's your issue most likely -> You'll have to request a change ZHA like done here for a different TRV, as this is outside the scope of BT.

If this is your TRV, the following limits are suggested by the Z2M implementation:

local_temperature_calibration (...) The minimal value is -9 and the maximum value is 9 with a step size of 0.5

[jensolsson]

I use the Nabu Casa SkyConnect, don't know if that is Z2M ?
But if I check in HA it seem to allow +/- 12.8 degrees.

[jensolsson]

I wonder if a specific firmware is needed for it to work fully ? I mean on the Sonoff TRV ?

[jensolsson]

@folfy here is the TRV I use
https://www.zigbee2mqtt.io/devices/TRVZB.html

[djoris]

Can't replicate this yet on my TRVZB, given the other tickets I see regarding this device I'm not going to extensively test yet ;)

Could the reported issue be due to BT not yet being trained? Or should an insufficiently trained BT only be able to cut off too late instead of too early?

I use the Nabu Casa SkyConnect, don't know if that is Z2M ? But if I check in HA it seem to allow +/- 12.8 degrees.
Can confirm TRVZB with ZHA gives -12.8℃ .. +12.7℃.
If you use 'default' setup in Home Assistant, you can assume you're using ZHA integration: "ZIgbee Home Automation". You can check in the integrations page.

[folfy]

Seems to be a bug of the SONOFF TRV sometimes not updating it's temperature after sending a new local calibration: Koenkk/zigbee2mqtt#19269 (comment)

This can cause BT local calibration to temporarily lockup, waiting for an update (i.e. till our target temperature or the TRV temperature changes). Target temperature calibration mode should be unaffected by this.

@jensolsson please provide debug logs and graphs of your issue as stated in #1568 (comment), or otherwise close this as a (most likely) duplicate issue.

[jensolsson]

@folfy thanks for the response.

I understand that switching to target temperature should not make a difference, but I must say that after doing so temperature works perfectly. So for me there was a huge difference.

Only downside now is that all TRVs shows an incorrect set temperature.

Will see if I can get some logs. Is this a good plan:

1. Enable debug logs for BT
2. Set one of the BT entries to offset mode
3. wait for the thermostat to be in the wrong state (for example idle when heat is needed)
4. save the log

[folfy]

@jensolsson Thanks, you could do that, but most likely it's just the same issue as already reported by multiple people in #1410, #1489, #1578 , and many more/older ones.

If you wanna provide logs and it proves to be a different roblem, we can reopen this issues, but if you're ok with target temperature calibration till we got a workaround for the underlying issue in the SONOFF TRV, I'd leave this closed as a duplicate / with workaround now.

[jensolsson]

Ah makes sense

I read this ” Target temperature calibration mode should be unaffected by this.” as if it would not affect the problem. But I understabd you mean it should be unaffected of the problem. That is great. Thanks