TRV's Opening/Closing degree and VTherm's Open percent don't match

[Seminko]

I have Sonoff TRVZB that is controlled by VTherm. I noticed something that started happening just now (start of new heating season) - Sonoff TVRZB shows different Valve Opening Degree than VTherm's Valve Open Percent. When it happend previously last season, the TVRZB used to get stuck somehow where VTherm was declaring different Valve Open Percents but the TRVZB valve was not physically moving, even the declared Valve Opening / Closing Degree was stuck at 0 / 100 on the Sonoff. Reconfiguration and HA restart always fixed the issue and it went away for a month or so. Now, the issue is different - nothing is stuck, the numbers are going up and down but they don't match. When opening/closing is 0/100, VTherm correctly shows 0%, but once the valve starts opening, the numbers stop matching, eg:

I used this difference to trigger a notification that something was wrong with the TRV and it needs a restart but now it pops all the time and I can't tell anymore.

Any idea how to fix it?

[jmcollin78]

Hello, give us your valve configuration. The answer is probably here

[Seminko]

Do you mean this?

If not, could you please be a little more specific as to what screen you want to see? Thanks

[jmcollin78]

Yes this is what I expect but nothing relevant here. I was wondering if you set the max/min/threshold opening/closing values which can explain the differences.

If you have the VTherm UI Card, can you check that you don't have delayed command (see: https://github.com/jmcollin78/versatile-thermostat-ui-card#update-of-underlying-scheduled for more info).
Else you will have to check the logs when this happens with this procedure: https://www.versatile-thermostat.org/en/docs/feature-logs-collector/)

[Seminko]

Yes this is what I expect but nothing relevant here. I was wondering if you set the max/min/threshold opening/closing values which can explain the differences.

If you have the VTherm UI Card, can you check that you don't have delayed command (see: https://github.com/jmcollin78/versatile-thermostat-ui-card#update-of-underlying-scheduled for more info). Else you will have to check the logs when this happens with this procedure: https://www.versatile-thermostat.org/en/docs/feature-logs-collector/)

Don't have the UI Card.
I'm exporting the logs using Developer Tools action and it doesn't work as intended...
Here's the head of the log output:

================================================================================
Versatile Thermostat - Log Export
Thermostat : Thermostat Child Room (climate.thermostat_child_room)
Period     : 2026-10-16 04:00:00 → 2026-10-16 10:00:00 UTC
Level      : DEBUG and above
Entries    : 0
Generated  : 2026-10-16 18:08:32 UTC

Despite the logs saying 0 entries, as I can clearly see that the Valve Open Percent changed during this period in HA:

entity_id	state	last_changed
sensor.thermostat_child_room_valve_open_percent	0	2026-10-16T04:00:00.000Z
sensor.thermostat_child_room_valve_open_percent	31	2026-10-16T04:00:00.218Z
sensor.thermostat_child_room_valve_open_percent	25	2026-10-16T04:06:51.718Z
sensor.thermostat_child_room_valve_open_percent	7	2026-10-16T04:21:49.404Z
sensor.thermostat_child_room_valve_open_percent	0	2026-10-16T04:36:47.050Z
sensor.thermostat_child_room_valve_open_percent	19	2026-10-16T05:40:01.542Z
sensor.thermostat_child_room_valve_open_percent	13	2026-10-16T05:51:35.196Z
sensor.thermostat_child_room_valve_open_percent	19	2026-10-16T06:21:30.615Z
sensor.thermostat_child_room_valve_open_percent	7	2026-10-16T06:36:28.282Z
sensor.thermostat_child_room_valve_open_percent	0	2026-10-16T06:51:25.879Z
sensor.thermostat_child_room_valve_open_percent	13	2026-10-16T08:06:14.095Z
sensor.thermostat_child_room_valve_open_percent	19	2026-10-16T08:21:11.746Z
sensor.thermostat_child_room_valve_open_percent	7	2026-10-16T08:36:09.425Z
sensor.thermostat_child_room_valve_open_percent	0	2026-10-16T08:51:07.033Z

Also, when I'm exporting 2026-10-15 18:00:00 → 2026-10-16 18:00:00 UTC I only see logs starting 2026-10-16 11:59:16.120, ending 2026-10-16 17:59:49.485. Mind you I'm exporting DEBUG.

 

EDIT: OK, for some reason I was able to download the logs for this morning. Here they are (Google Drive).. I haven't found anything out of the ordinary the valve open percent values seem to match shifted values I see directly in HA (brief check), but then again I have no idea what to look for.

Here is what to compare the logs to:

last_changed	Sonoff opening degree	Vtherm valve open percent	DIFF
2026-10-15T22:00:00.000Z	0	0	0
2026-10-16T04:00:02.212Z	27	31	4
2026-10-16T04:06:52.262Z	21	25	4
2026-10-16T04:21:51.265Z	2	7	5
2026-10-16T04:36:49.199Z	0	0	0
2026-10-16T05:40:02.090Z	15	19	4
2026-10-16T05:51:35.641Z	8	13	5
2026-10-16T06:21:32.419Z	15	19	4
2026-10-16T06:36:28.794Z	2	7	5
2026-10-16T06:51:26.971Z	0	0	0
2026-10-16T08:06:14.598Z	8	13	5
2026-10-16T08:21:13.049Z	15	19	4
2026-10-16T08:36:11.574Z	2	7	5
2026-10-16T08:51:07.953Z	0	0	0
2026-10-17T04:00:00.801Z	34	37	3
2026-10-17T04:18:06.270Z	15	19	4
2026-10-17T04:33:05.542Z	0	0	0
2026-10-17T06:17:47.903Z	2	7	5
2026-10-17T06:35:23.162Z	0	0	0
2026-10-17T06:47:05.703Z	2	7	5
2026-10-17T06:52:14.793Z	21	25	4
2026-10-17T07:02:41.426Z	15	19	4
2026-10-17T07:17:39.963Z	2	7	5

[jmcollin78]

Hello, you have a 5 min regulation delay which explains what you see:
2026-10-17 04:32:38.858 INFO [thermostat_climate] Thermostat Child Room - period (0.5) min is < 5 min -> forget the auto-regulation send

The is the parameter named: minimum regulation period (in FR):

This is visible on the VTherm UI Card as I explain above.

[jmcollin78]

Ok, i will make a check with my test Sonoff TRVZB. Which release do you have ?

[jmcollin78]

What are the values you see @grossermax ?
12 in VTherm and 7 in the valve ?

[grossermax]

VTherm: 10.5.1
VTherm UI Card: 3.4.0
Home Assistant Core: 2026.9.4 (I plan to update to 2026.10.2 within the next two days)

[grossermax]

What are the values you see @grossermax ? 12 in VTherm and 7 in the valve ?

Yes, correct. According my valve configuration this is what I see.
Similar for all my other four Sonoff TRVZB (I checked today's history.)

[Seminko]

My VTherm is 10.4.0 for the record

[jmcollin78]

If I look at my TRVZB, I see that:

but the valve is open at 7%:

This is due to my configuration of the regulation (max_closing_degree in my case):

So for me this is normal and that is why I ask the configuration.

i will continue more tests

[jmcollin78]

More test. When heating is needed and not at 100% with all my parameters to the default values (0 and 100%), I think I reproduce the issue:

and

[jmcollin78]

I will transform this into an issue.

[Seminko]

Good job. Once you figure it out, pls let us know. I'd be curious what caused it and if this was just a "visual bug" or if it influenced anything. Thanks!

EDIT: I'll track the issue when you post it.

EDIT: subbed to the issue, thanks

[jmcollin78]

If I set the regulation_threshold to 0, the decrepency disapear.
This parameter is explained here: https://www.versatile-thermostat.org/en/docs/over-climate/#self-regulation

Regulation Threshold: a threshold in ° (or %) below which a new setpoint will not be sent.

This is named seuil de régulation in French:

What happens is that, when the min_opening_degree is set to 0, then this value is used. So you think you have 0 as min, but the real value used is 5 (the regulation_threshold).

So, when a value needs to be send to the TRVZB, Vtherm calculated the send value with those rules: https://github.com/jmcollin78/versatile_thermostat/blob/main/documentation/en/self-regulation.md#configuration

If you use the regulation parameter regulation_threshold (see over_climate regulation), then the opening_threshold will be adjusted so that it is never below this value. Indeed, the regulation_threshold is the regulation unit below which the setpoint is not sent. Setting an opening_threshold would have no effect.

In conclusion, this is normal but misleading I agree with you.

So I close the issue but put this discussion at the top.

[Seminko]

Updated to 10.6.1 where the fix was merged but still not resolved:

[jmcollin78]

This is not a fix but a documentation addition. The behavior is normal. Please read the discussion.

[Seminko]

For example, if VTherm calculates a raw heating demand of 12% (valve_open_percent: 12), this threshold is taken into account when calculating the valve command. As a result, an opening degree of 7% is ultimately sent to the TRV:
12% VTherm heating demand − 5% threshold = 7% valve opening

Now two things:
12% VTherm heating demand − 5% threshold = 7% valve opening - this is not always the case, see the table HERE. Sometimes the difference is 4, sometimes even 3.

 

Also, I don't understand why the threshold would influence the valve opening. You said:

regulation_threshold - Regulation Threshold: a threshold in ° (or %) below which a new setpoint will not be sent.

To me that sounds like if VTherm wants to increase the valve opening by <5% it will not do so, because of this threshold. That makes perfect sense - we don't want the valve constantly opening and closing a percent here, a percent there. But if the valve should open by 5% or more, this is outside of this threshold, why would it influence the valve open percent at all?

 

Also2, what does not make sense to me is that VTherm is claiming the valve is 7% open, whereas in reality it is open 12%. This is a naming issue IMO. If the name is "valve_open_percent" it should mean how many percent the valve is open in absulute terms, regardless of other options, in other words it should match the actual TRV. If you want it to indicate something else, it should be name something else, eg valve_open_percent_relative

[jmcollin78]

VTherm is claiming the valve is 7% open

VTherm want to heat at 7% of power which means the valve open at 12%. That is the correct way to understand.
This has been discussed during a long time and very difficult to find a usable way for every one. I don't to reopen this subject.
Take it as a fact. See (137 responses to this discussions) : #1220

[Seminko]

Fair enough. Thanks for your time and effort.