Unexpected over_switch behavior: either doesn't trigger or trigger only to 300s

[PokePango]

Hello,

I'm having a weird issue that came up only recently while testing a few variations on my VTherm.

My current issues are as follow:

• The VTherm triggers heating only if I set a much higher target temperature; for example:
  • hvac_action: idle
    • current_temperature: 14.1
    • temperature: 15
  • hvac_action: heating
    • current_temperature: 14.1
    • temperature: 16
• The VTherm displays no transient states:
  • either hvac_action: heating, sensor.vtherm_switch_on_time = 300s and sensor.vtherm_switch_off_time = 0s
  • or hvac_action: idle, sensor.vtherm_switch_on_time = 0s and sensor.vtherm_switch_off_time = 300s (expected)

The current setup is straightforward: one radiator that displays a switch entity is linked to an external temperature sensor through a VTherm. Here are the details of the configuration (while idle):

hvac_modes:
  - heat
  - "off"
min_temp: 7
max_temp: 26
target_temp_step: 0.1
preset_modes:
  - none
  - frost
  - eco
  - comfort
  - boost
current_temperature: 14.1
temperature: 15
hvac_action: idle
preset_mode: none
is_on: true
hvac_mode: heat
type: null
is_controlled_by_central_mode: true
last_central_mode: Heat only
frost_temp: 7
eco_temp: 13
boost_temp: 17
comfort_temp: 15
frost_away_temp: 0
eco_away_temp: 0
boost_away_temp: 0
comfort_away_temp: 0
target_temperature_step: 0.1
ext_current_temperature: -1.2
ac_mode: false
saved_preset_mode: none
saved_target_temp: 7
saved_hvac_mode: heat
last_temperature_datetime: "2025-01-14T22:52:00.569026+01:00"
last_ext_temperature_datetime: "2025-01-14T22:52:00.627787+01:00"
minimal_activation_delay_sec: 300
total_energy: 3.78
last_update_datetime: "2025-01-14T22:59:32.439184+01:00"
timezone: Europe/Paris
temperature_unit: °C
is_device_active: false
device_actives: []
nb_device_actives: 0
ema_temp: 14.1
is_used_by_central_boiler: false
temperature_slope: 0
hvac_off_reason: null
max_on_percent: null
have_valve_regulation: false
last_change_time_from_vtherm: "2025-01-14T22:59:32.437177+01:00"
presence_sensor_entity_id: null
presence_state: unavailable
is_presence_configured: false
power_sensor_entity_id: null
max_power_sensor_entity_id: null
overpowering_state: unavailable
is_power_configured: false
device_power: 1
power_temp: null
current_power: null
current_max_power: null
mean_cycle_power: 0
motion_sensor_entity_id: null
motion_state: unavailable
is_motion_configured: false
motion_delay_sec: 30
motion_off_delay_sec: 300
motion_preset: comfort
no_motion_preset: eco
window_state: unavailable
window_auto_state: unavailable
window_action: window_turn_off
is_window_bypass: false
window_sensor_entity_id: null
window_delay_sec: null
window_off_delay_sec: null
is_window_configured: false
is_window_auto_configured: false
window_auto_open_threshold: null
window_auto_close_threshold: null
window_auto_max_duration: null
is_safety_configured: true
safety_state: "off"
safety_delay_min: 60
safety_min_on_percent: 0.7
safety_default_on_percent: 0.4
is_over_switch: true
is_inversed: false
keep_alive_sec: 0
underlying_entities:
  - switch.chauffage_salon
on_percent: 0
power_percent: 0
on_time_sec: 0
off_time_sec: 300
cycle_min: 5
function: tpi
tpi_coef_int: 0.6
tpi_coef_ext: 0.01
calculated_on_percent: 0
friendly_name: VTherm Switch salon
supported_features: 401

I've also included a screenshot from my last run (when heating was enabled it was because I triggered the switch manually):

I've already tried to remove it and create a new VTherm from scratch to no avail. I think I'm missing something but I feel like I've tried everything.

Thanks for your help!

[jmcollin78]

Hello,

For information, in over_switch, hvac_action is 'on' if and only if the switch is 'on'. But that is not your concern.

Your issue is that you have configured the minimal activation delay to 5 min (300 sec) but your cycle is also 5 min.
So it will heat only if the power_percent calculated by the TPI is 100%.

Set the minimal activation delay to 10 sec (to avoid turning 'on' the switch for less than 10 sec which is useless).

More information here: https://github.com/jmcollin78/versatile_thermostat/blob/main/documentation/fr/feature-advanced.md#d%C3%A9lai-minimal-dactivation

[PokePango]

Thank you, I was going crazy over this... I made the mistake of changing the default value from the central configuration at some point and forgot about it.

That also explains why it wasn't starting at all when the delta was small, which I thought might be a different issue.

Thanks!