Initial setup questions and setting up automation with smart trvs, and understanding SAT

[shant1993]

Hello, I have several questions about SAT. I’m new to Home Assistant, so please bear with me. I’ve read the discussions and tried to understand as much as I could.

I apologize for writing so long!, Thank you.

I am not using better thermostat with SAT (Should I?)

Setup

• Boiler, Unical !DEA CS24 combi with OpenTherm (device_id 16.0 in sensors)
• Controller, Ihor Melnyk’s OpenTherm adapter with ESPHome firmware

Heating plan

• Final goal, 4 rooms, each room with 1 radiator. (1 Sonoff TRV TRVZB, 1 Sonoff SNZB-02D thermometer)
• Current test, 1 room with 1 TRV and 1 thermometer

ESPHome configuration, what each selection means

Device
Is this the OpenTherm controller connected to the boiler, meaning Ihor’s adapter with the flashed firmware? It’s the only option shown.

Inside sensor entity
I selected the room thermometer, SNZB-02D.

Outside sensor entity
Currently using Home Assistant weather as a placeholder until my SNZB-02LD arrives.

Humidity sensor entity
Also using the room thermometer, SNZB-02D.

I selected Radiators as the heating type.

Areas page, confusion

This part is unclear to me.

Thermostat
Is this supposed to be the OpenTherm controller, same as the Device above?
Right now, I only see my room TRV listed here.

Radiator
I assume this should be the living room TRV.
Again, only my single TRV shows up.

Rooms
I expected this to list other room TRVs, but I only see the same TRV, which makes sense since I only have one.

Questions about behavior

• If my understanding is correct, why doesn’t the Thermostat field show the OpenTherm device connected to the boiler?
• Why are Radiators and Rooms separated instead of grouped together?
• Does SAT actually control the smart TRVs, or do they operate independently?
• If they are independent, how do they coordinate with SAT and OpenTherm or PID control?

What I tried

• Set thermometer and TRV reporting interval to 30 seconds
• Selected Ihor’s adapter as Device
• Used the room thermometer for inside temperature and humidity
• Used Home Assistant weather for outside
• In Areas, only filled Radiators entry with my TRV, left others empty. Also tried both thermostat and radiators entry with my trv, none of which helped auto calib from finishing.

The auto calibration never finishes. and here's what i noticed from logs.

From HA core logs, it repeatedly says “waiting for a stable temperature” until it times out, then stops, while calibration keeps spinning for hours.

026-03-18 17:23:20.391 WARNING (MainThread) [custom_components.sat.overshoot_protection] Waiting for a stable temperature
2026-03-18 17:23:35.396 WARNING (MainThread) [custom_components.sat.overshoot_protection] Waiting for a stable temperature
2026-03-18 17:23:50.138 WARNING (MainThread) [custom_components.sat.config_flow] Timed out during overshoot protection calculation.

Zigbee2MQTT logs:

[2026-03-18 14:08:53] �[32minfo�[39m: z2m:mqtt: MQTT publish: topic 'zigbee2mqtt/radiator smart TRV', payload '{"battery":98,"child_lock":"UNLOCK","closing_steps":368,"external_temperature_input":22,"frost_protection_temperature":7,"idle_steps":173,"linkquality":163,"local_temperature":25.2,"local_temperature_calibration":0.1,"occupied_heating_setpoint":24,"open_window":"OFF","running_state":"heat","smart_temperature_control":true,"system_mode":"heat","temperature_accuracy":-1,"temperature_sensor_select":"external_2","temporary_mode_duration":0,"temporary_mode_select":"boost","timer_mode_target_temp":4.5,"update":{"installed_version":5124,"latest_release_notes":null,"latest_source":"https://raw.githubusercontent.com/Koenkk/zigbee-OTA/master/images/Sonoff/trvzb_v1.4.4.ota","latest_version":5124,"state":"idle"},"valve_closing_degree":100,"valve_closing_limit_voltage":2657,"valve_motor_running_voltage":1598,"valve_opening_degree":100,"valve_opening_limit_voltage":1696,"weekly_schedule_friday":"00:00/16 07:00/19 10:00/16 10:00/16 17:00/19 23:00/16","weekly_schedule_monday":"00:00/16 07:00/19 10:00/16 10:00/16 17:00/19 23:00/16","weekly_schedule_saturday":"00:00/16 07:00/19 10:00/19 10:00/19 10:00/19 23:00/16","weekly_schedule_sunday":"00:00/16 07:00/19 10:00/19 10:00/19 10:00/19 23:00/16","weekly_schedule_thursday":"00:00/16 07:00/19 10:00/16 10:00/16 17:00/19 23:00/16","weekly_schedule_tuesday":"00:00/16 07:00/19 10:00/16 10:00/16 17:00/19 23:00/16","weekly_schedule_wednesday":"00:00/16 07:00/19 10:00/16 10:00/16 17:00/19 23:00/16"}'

[2026-03-18 14:35:00] �[32minfo�[39m: z2m:mqtt: MQTT publish: topic 'zigbee2mqtt/radiator smart TRV', payload '{"battery":98,"child_lock":"UNLOCK","closing_steps":368,"external_temperature_input":22,"frost_protection_temperature":7,"idle_steps":173,"linkquality":156,"local_temperature":26.7,"local_temperature_calibration":0.1,"occupied_heating_setpoint":24,"open_window":"OFF","running_state":"idle","smart_temperature_control":true,"system_mode":"heat","temperature_accuracy":-1,"temperature_sensor_select":"external_2","temporary_mode_duration":0,"temporary_mode_select":"boost","timer_mode_target_temp":4.5,"update":{"installed_version":5124,"latest_release_notes":null,"latest_source":"https://raw.githubusercontent.com/Koenkk/zigbee-OTA/master/images/Sonoff/trvzb_v1.4.4.ota","latest_version":5124,"state":"idle"},"valve_closing_degree":100,"valve_closing_limit_voltage":2657,"valve_motor_running_voltage":1780,"valve_opening_degree":100,"valve_opening_limit_voltage":1696,"weekly_schedule_friday":"00:00/16 07:00/19 10:00/16 10:00/16 17:00/19 23:00/16","weekly_schedule_monday":"00:00/16 07:00/19 10:00/16 10:00/16 17:00/19 23:00/16","weekly_schedule_saturday":"00:00/16 07:00/19 10:00/19 10:00/19 10:00/19 23:00/16","weekly_schedule_sunday":"00:00/16 07:00/19 10:00/19 10:00/19 10:00/19 23:00/16","weekly_schedule_thursday":"00:00/16 07:00/19 10:00/16 10:00/16 17:00/19 23:00/16","weekly_schedule_tuesday":"00:00/16 07:00/19 10:00/16 10:00/16 17:00/19 23:00/16","weekly_schedule_wednesday":"00:00/16 07:00/19 10:00/16 10:00/16 17:00/19 23:00/16"}'

There's more logs with all the same, i only copied the ones that matter, so my connection and reporting intervals are fine.

Here's the part that's confusing me.

I set the TRV target to 26°C. The TRV detects its own temperature going above that and closes the valve.

• Shouldn’t it use the external room thermometer instead, since that’s what I selected in SAT?

I read a comment on another discussion that SAT only reads TRVs and does not control them.

• If that’s true, how are valve adjustments coordinated?
• OpenTherm or PID on the adapter is supposed to handle efficiency and overshoot, but wouldn’t that require controlling the TRVs?

From what I understand:

• SAT calculations are based on a single indoor sensor, meaning the room thermometer
• The Rooms section seems to rely on the temperature reported by each smart TRV

This leads to a few questions.

• Are the temperatures from the smart TRVs actually used when making OpenTherm decisions, or is everything based only on the indoor sensor temperature?

• If SAT is mainly using the indoor thermometer for its calculations, then what role do the TRV temperatures play in the process?

• Based on this, would it make more sense to reconfigure the smart TRVs in Home Assistant to use an external room thermometer instead of their internal temperature readings?

Everything else asked, is there any way I can get more logs from what exactly SAT is doing and where it's getting stuck during it's auto calibration process? it's not available in system/logs as an integration during the auto calibration process.

My goal: To get the efficiency of opentherm, PID, relying on temps of the room thermometer, using smart trv to open/close valves with automation in coordination with the boiler, be able to set room temperatures directly on each TRV so SAT can react to those changes for each individual room.

Thanks again.