Heating when not requested

[trxman]

Hi.
I am using Versatile Thermostat 8.6.2 via Zigbee2MQTT on my HO VM.
4 SONOFF TRVZBs with firmware 1.4.4 are working fine.
Nevertheless, I have one valve identified as Nedis ZBHTR20WT very often heats even when not requested:

On the screenshot it's obvious that room temperature is ~21°C and target temp is always set far below it. However, valve is very often in the heating mode.

How can this situation be further debugged?

Thx.

[jmcollin78]

Hello @trxman,

As described in the issue template to help with such issue you should give us:

1. your VTherm attributes (https://github.com/jmcollin78/versatile_thermostat/blob/main/documentation/en/reference.md#custom-attributes),
2. some regulation curves (https://github.com/jmcollin78/versatile_thermostat/blob/main/documentation/en/additions.md#regulation-curves-with-plotly-to-fine-tune-your-thermostat)

[trxman]

Thx for directions.

hvac_modes:
  - "off"
  - heat
min_temp: 7
max_temp: 35
target_temp_step: 0.1
preset_modes:
  - none
  - frost
  - eco
  - comfort
  - boost
current_temperature: 22.5
temperature: 11
hvac_action: idle
preset_mode: none
hvac_mode: heat
ema_temp: 22.52
specific_states:
  is_on: true
  last_central_mode: null
  last_update_datetime: "2026-03-07T12:18:32.441433+01:00"
  ext_current_temperature: 11.9
  last_temperature_datetime: "2026-03-07T12:17:12.436461+01:00"
  last_ext_temperature_datetime: "2026-03-07T11:54:21.915025+01:00"
  is_device_active: false
  device_actives: []
  nb_device_actives: 0
  ema_temp: 22.52
  temperature_slope: -0.18
  hvac_off_reason: null
  total_energy: 136.91
  last_change_time_from_vtherm: "2026-03-07T12:03:21.070243+01:00"
  messages: []
  is_sleeping: false
  is_locked: false
  is_recalculate_scheduled: true
configuration:
  ac_mode: false
  type: over_climate
  is_controlled_by_central_mode: false
  target_temperature_step: 0.1
  timezone: Europe/Vienna
  temperature_unit: °C
  is_used_by_central_boiler: false
  max_on_percent: null
  have_valve_regulation: false
  cycle_min: 5
preset_temperatures:
  frost_temp: 7
  eco_temp: 12
  boost_temp: 18
  comfort_temp: 16
  frost_away_temp: 0
  eco_away_temp: 0
  boost_away_temp: 0
  comfort_away_temp: 0
current_state:
  hvac_mode: heat
  target_temperature: 11
  preset: none
requested_state:
  hvac_mode: heat
  target_temperature: 11
  preset: none
is_presence_configured: false
is_power_configured: false
power_manager:
  device_power: 1
  mean_cycle_power: 0
is_motion_configured: false
is_window_configured: true
is_window_auto_configured: false
window_manager:
  window_state: "off"
  window_auto_state: unavailable
  window_action: window_turn_off
  is_window_bypass: false
  window_sensor_entity_id: binary_sensor.sensor_window_bathroom_contact
  window_delay_sec: 30
  window_off_delay_sec: 180
  window_auto_open_threshold: null
  window_auto_close_threshold: null
  window_auto_max_duration: null
is_safety_configured: true
safety_manager:
  safety_state: "off"
  safety_delay_min: 60
  safety_min_on_percent: 0.5
  safety_default_on_percent: 0.1
is_lock_configured: true
lock_manager:
  is_locked: false
  lock_users: true
  lock_automations: true
  lock_code: false
timed_preset_manager:
  is_active: false
  preset: null
  end_time: null
  remaining_time_min: 0
is_heating_failure_detection_configured: false
is_auto_start_stop_configured: true
auto_start_stop_manager:
  auto_start_stop_enable: false
  auto_start_stop_level: auto_start_stop_none
  auto_start_stop_dtmin: null
  auto_start_stop_accumulated_error: 0
  auto_start_stop_accumulated_error_threshold: null
  auto_start_stop_last_switch_date: null
  is_auto_stop_detected: false
fan_mode: null
fan_modes: []
is_over_climate: true
regulation_accumulated_error: 0
regulated_target_temperature: 11
vtherm_over_climate:
  start_hvac_action_date: null
  last_mean_power_cycle: 0
  underlying_entities:
    - climate.radiator_bathroom
  is_regulated: false
  auto_fan_mode: auto_fan_high
  current_auto_fan_mode: auto_fan_high
  auto_activated_fan_mode: null
  auto_deactivated_fan_mode: null
  follow_underlying_temp_change: false
  auto_regulation_use_device_temp: false
friendly_name: VTherm Bathroom
supported_features: 401

  type: custom:plotly-graph
  entities:
    - entity: 'climate.vtherm_bathroom'
      attribute: temperature
      yaxis: y1
      name: Wanted
    - entity: 'climate.vtherm_bathroom'
      attribute: current_temperature
      yaxis: y1
      name: T°
    - entity: 'sensor.vtherm_bathroom_ema_temperature'
      yaxis: y1
      name: Ema
    - entity: 'sensor.bathroom_heating_active'
      yaxis: y2
      name: Heating
      fill: tozeroy
      fillcolor: rgba(200, 10, 10, 0.3)
      line:
        color: rgba(200, 10, 10, 0.9)
    - entity: 'sensor.vtherm_bathroom_temperature_slope'
      name: Slope
      fill: tozeroy
      yaxis: y9
      fillcolor: rgba(100, 100, 100, 0.3)
      line:
        color: rgba(100, 100, 100, 0.9)
  hours_to_show: 4
  refresh_interval: 10
  height: 800
  config:
    scrollZoom: true
  layout:
    margin:
      r: 50
    legend:
      x: 0
      'y': 1.2
      groupclick: togglegroup
      title:
        side: top right
    yaxis:
      visible: true
      position: 0
    yaxis2:
      visible: true
      position: 0
      fixedrange: true
      range:
        - 0
        - 1
    yaxis9:
      visible: true
      fixedrange: false
      range:
        - -2
        - 2
      position: 1
    xaxis:
      rangeselector:
        'y': 1.1
        x: 0.7
        buttons:
          - count: 1
            step: hour
          - count: 12
            step: hour
          - count: 1
            step: day
          - count: 7
            step: day
            

[jmcollin78]

Ok I see. You have a "simple" Over_climate VTherm. In that case, all VTherm does is to send the sendpoint to the underlying climate.radiator_bathroom device. And this device, decide by itself to heat or not depending on its internal temperature sensor.

So you are certainly subject to the "very bad internal temperature sensor" issue of your device.
The way to fix that is the self-regulation: VTherm will adapt the setpoint of your climate until the target is reached in the room temperature sensor. This is explained here: https://www.versatile-thermostat.org/fr/docs/self-regulation/

Turn it on, choose the correct level (starts with high in your case) and it should be much better.

If not, you can try the option "use the internal temp sensor" to see but with bad internal sensor, it is often worst.

[caiusseverus]

There is another problem - the TRVZB only has 0.5º resolution for its set temperatures. It will accept you setting something else (eg 20.7º) but after a short period it will revert to the nearest 0.5º step, eg 20.5ºC.

[trxman]

Using self-regulation seems to solve the problem. Thx.

@TRVZB - 4 of them work fine for me, as they are controlled directly by % of valve opening. The problematic one is Nedis ZBHTR20WT, which is a simple ON/OFF which depends on target temperature set on it.

[trxman]

Solved.