Fluctulating temperature with climate / valve control (Sonoff)

[Seminko]

My temperature seems to be fluctulating quite a bit as you can see here:

I don't think that's normal / ideal? From what I understand it should be as flat as possible so that the TRV doesn't have to be triggered every 30 minutes like it is now.

I'm using Sonoff TRVZB + Sonoff SNZB-02P, so climate valve control. In the building where my flat is there is centralized heating. Also maybe worth mentioning is that all other TRVs in my flat are "dumb" TRVs - I'm testing this single one just because the TRV location is bad - holds temperature, so hence smart TRV + external thermometer further away from the radiator.

I found this thread which suggested lowering coef_int - I tried lowering it from the default to 0.4.

Currently in Eco mode, so no heating. Will see tomorrow if something changes. If it doesn't what else can I try?

EDIT: also forgot to mention that the radiator water temperature is also controlled centrally, ie when it's colder outside the water is hotter and when it's not so cold the water is less hot. Will VThem still be usable in an ideal fashion?

[jmcollin78]

Hello, lowering coef_int is the correct way to handle oscillations.

[Seminko]

Tried playing with it, no luck. It went all over the place. Now I reverted back to the original default settings for coef_int and coef_ext which previously kept on temperature with fluctulations. The fluctulations remain but now the temperature doesn't reach the target which it previously did with these settings. Currently it sits 0.3C below the target with the valve being open only 19%.

[jmcollin78]

As described in the documentation (see TPI algo tuning):

1. first tune the coef_int to avoid oscillation (set it at max when you don't have oscillations or very small),
2. then tune the coef_ext. Increase if setpoint is not reach, decrease in case of overshoot

[Seminko]

As described in the documentation (see TPI algo tuning):

1. first tune the coef_int to avoid oscillation (set it at max when you don't have oscillations or very small),
2. then tune the coef_ext. Increase if setpoint is not reach, decrease in case of overshoot

Tried to do just that. How big the steps for lowering coef_int should be? How do I know I overshot and I should increase it again?

[jmcollin78]

I would try with dichotomy :

0,6 -> 0,3 -> 0,4
-> 0.2 ... etc

[Seminko]

I went all the way from the default 0.6 to 0.2 by 0.05 increments and despite seeing some change for the better, it still switches all the time - usually every 30 minutes, sometimes even 5 minutes. The longest time without the valve opening changing was almost an hour but that happens like once a day.

Do I go lower than 0.2? That doesn't seem right...

[Seminko]

Custom attributes here:

hvac_modes: heat, sleep, off
min_temp: 7
max_temp: 35
target_temp_step: 0.1
preset_modes: none, frost, eco, comfort, boost
current_temperature: 21.2
temperature: 22
hvac_action: heating
preset_mode: comfort
hvac_mode: heat
ema_temp: 21.19
is_ready: true
specific_states: 
is_initialized: true
is_on: true
last_central_mode: null
last_update_datetime: '2026-02-19T22:03:35.573642+01:00'
ext_current_temperature: 3.4
last_temperature_datetime: '2026-02-19T21:15:05.470034+01:00'
last_ext_temperature_datetime: '2026-02-19T22:01:18.151427+01:00'
should_device_be_active: true
is_device_active: false
device_actives:
- number.sonoff_trvzb_valve_opening_degree
nb_device_actives: 1
ema_temp: 21.19
temperature_slope: 0
hvac_off_reason: null
total_energy: 62.2
last_change_time_from_vtherm: '2026-02-19T22:03:35.572318+01:00'
is_sleeping: false
is_locked: false
is_recalculate_scheduled: false
not_initialized_entities: []
messages: []
auto_tpi_state: 'off'
auto_tpi_learning: {}

configuration: 
ac_mode: false
type: over_climate_valve
is_controlled_by_central_mode: false
target_temperature_step: 0.1
timezone: Europe/Prague
temperature_unit: °C
is_used_by_central_boiler: false
max_on_percent: null
have_valve_regulation: true
cycle_min: 5
minimal_activation_delay_sec: 10
minimal_deactivation_delay_sec: 0

preset_temperatures: 
frost_temp: 7
eco_temp: 18
boost_temp: 23.5
comfort_temp: 22
frost_away_temp: 0
eco_away_temp: 0
boost_away_temp: 0
comfort_away_temp: 0

current_state: 
hvac_mode: heat
target_temperature: 22
preset: comfort

requested_state: 
hvac_mode: heat
target_temperature: 22
preset: comfort

is_presence_configured: false
is_power_configured: false
power_manager: 
device_power: 1
mean_cycle_power: 0.22

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.myggbett_door_window_sensor_door
window_delay_sec: 10
window_off_delay_sec: 60
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: false
fan_mode: null
fan_modes: 
is_over_climate: true
regulation_accumulated_error: 0
regulated_target_temperature: null
vtherm_over_climate: 
start_hvac_action_date: null
last_mean_power_cycle: 0
underlying_entities:
- climate.sonoff_trvzb_1_thermostat
is_regulated: true
auto_fan_mode: auto_fan_high
current_auto_fan_mode: auto_fan_none
auto_activated_fan_mode: null
auto_deactivated_fan_mode: null
follow_underlying_temp_change: false
auto_regulation_use_device_temp: false
regulation:
regulated_target_temperature: null
auto_regulation_mode: auto_regulation_valve
regulation_accumulated_error: 0

valve_open_percent: 22
power_percent: 22
on_percent: 0.22
vtherm_over_climate_valve: 
have_valve_regulation: true
valve_regulation:
underlyings_valve_regulation:
  - - number.sonoff_trvzb_valve_opening_degree
    - number.sonoff_trvzb_valve_closing_degree
on_percent: 0.22
power_percent: 22
function: tpi
tpi_coef_int: 0.25
tpi_coef_ext: 0.001
tpi_threshold_low: 0
tpi_threshold_high: 0
minimal_activation_delay: 10
minimal_deactivation_delay: 0
min_opening_degrees: ''
opening_threshold_degree: 0.3
max_closing_degree: 100
max_opening_degrees: ''
valve_open_percent: 22
auto_regulation_dpercent: 0.3
auto_regulation_period_min: 5
last_calculation_timestamp: '2026-02-19T21:15:05.472641+01:00'
underlying_valves:
number.sonoff_trvzb_valve_opening_degree:
  hvac_action: heating
  percent_open: 22
  last_sent_opening_value: 22
  min_opening_degree: 0
  max_opening_degree: 100

friendly_name: Thermostat Child Room
supported_features: 401

As for the regulation curve, i had issues setting up the plotly graph. Hopefully it's ok:

[jmcollin78]

Hello @Seminko,

Very sorry but you curve is too strange. I don't understand what I see. The left axis has no order (how you do that ?!), I don't see the room temp (T°) and not sure where is the target temps. What I should see is something like that:

I need the target temp, the room temp and the power percent:

In the attributes:
opening_threshold_degree: 0.3 this is wrong. Maybe you want to set 30 (as 30%)
auto_regulation_dpercent: 0.3 this is wrong. Set it to 5 (for valve this is percent)

Other value seems good.

[Seminko]

Very sorry but you curve is too strange. I don't understand what I see. The left axis has no order (how you do that ?!), I don't see the room temp (T°) and not sure where is the target temps.

I followed the instruction in the link you posted..

Here's the yaml for the plotly graph

type: custom:plotly-graph
entities:
- entity: climate.thermostat_child_room
  attribute: temperature
  yaxis: y1
  name: Wanted
- entity: climate.thermostat_child_room
  attribute: current_temperature
  yaxis: y1
  name: T°
- entity: sensor.thermostat_child_room_ema_temperature
  yaxis: y1
  name: Ema
- entity: sensor.thermostat_child_room_power_percent
  yaxis: y2
  name: Power percent
  fill: tozeroy
  fillcolor: rgba(200, 10, 10, 0.3)
  line:
    color: rgba(200, 10, 10, 0.9)
- entity: sensor.thermostat_child_room_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

What plotly "integration" do you use? I have:

---

In the attributes:
opening_threshold_degree: 0.3 this is wrong. Maybe you want to set 30 (as 30%)
auto_regulation_dpercent: 0.3 this is wrong. Set it to 5 (for valve this is percent)

I found these>


Already changed it to 5.

---

Also a bit unrelated, for some reason every couple of days there is a disconnect between the sonoff trvzb integration and vtherm, for example currently:
VTherm says Valve open percent = 11%
Sonoff TRVZB says Valve opening degree = 6%
Last time this happened VTherm reported 0% while in reality it was fully opened and I woke up with 4C over the target temperature.

[Seminko]

@jmcollin78 Any other insights pls?

[jmcollin78]

Hello, no sorry, you have something wrong in your installation and I can't figure out what it is. Your parameters seems good, your curves are too strange. I have never seen that before. This is not something which looks like temperature regulation.