Sonoff TRV Gen2 – Thermostatic radiator valve with IPS display, Zigbee, Bluetooth, white (TRV-ZBT)

SONOFF TRV Gen2 (TRV-ZBT) is a Zigbee thermostatic radiator valve with a color IPS display, programmable temperature control, and support for an external temperature sensor. Installed on a radiator valve, it automatically regulates the flow of hot water according to the set target temperature. In addition to the standard M30 × 1.5 mm connection, the included adapters allow it to be fitted to several other valve types.

The TRV Gen2 features a 38% more compact design than the previous TRVZB model. It supports three separate scheduling plans, with up to 12 time periods configurable for each day of the week within each plan. In addition to the built-in temperature sensor, a compatible external SONOFF temperature sensor can also be selected as the reference value, which can reduce control inaccuracies caused by the higher temperature measured in the immediate vicinity of the radiator.

Valve control can be used with both traditional hysteresis-based and adaptive control. In adaptive mode, the device continuously adjusts the valve opening based on the difference between the target and measured temperature. The valve opening and closing percentage can also be set manually. The device operates with two AA alkaline batteries and can be integrated via Zigbee into eWeLink, Home Assistant, Zigbee2MQTT, ZHA, SmartThings, and several other compatible systems.

About SONOFF

SONOFF manufactures smart home devices, relay modules, energy meters, wall switches, Zigbee sensors, control panels, gateways, and various electrical installation accessories. Its product range includes devices using Wi-Fi, Zigbee, Matter, and LAN communication.

SONOFF devices are primarily built around the eWeLink platform, but many products can also be integrated with Home Assistant, Zigbee2MQTT, ZHA, SmartThings, Alexa, Google Home, and other smart home systems. In addition to residential smart home solutions, the manufacturer's range also includes DIN rail-mounted devices, energy monitoring solutions, and products suitable for professional installation.

Key Product Features

• Compact design: The TRV Gen2 is 38% smaller than the previous TRVZB generation.
• Three scheduling plans: Three separate weekly schedules can be created and switched between as required.
• Up to 12 periods per day: Each schedule can include up to 12 separate temperature periods for every day of the week.
• Two types of open-window detection: The device can automatically detect an open window based on a rapid temperature drop, or it can be linked with a compatible door/window sensor.
• External temperature source: A compatible SONOFF temperature sensor can be used as the reference value for temperature control.
• Color IPS display: Displays information including the set and current temperature, operating mode, heating status, and Zigbee signal strength.
• Four-way display rotation: The display orientation can be rotated in 90° increments.
• Adaptive control: The device can dynamically adjust valve opening based on temperature changes and the target temperature.
• Valve opening adjustment: The valve opening and closing ratio can be configured between 0–100% when adaptive mode is disabled.
• Automatic anti-scale valve movement: Every Monday at 12:00, the valve automatically performs a maintenance cycle to reduce the risk of sticking.

Smart Home Protocols and Platform Compatibility

• Zigbee: Uses IEEE 802.15.4-based Zigbee communication. A compatible Zigbee gateway or coordinator is required for normal operation.
• eWeLink: With a SONOFF Zigbee gateway, the fuller feature set is available in the eWeLink app, including schedules, external temperature source, adaptive control, valve opening ratio, and notifications.
• SONOFF Zigbee gateways: The manufacturer recommends the ZBBridge-P, ZBBridge-U, NSPanel Pro, and iHost models. Additional supported SONOFF coordinators include ZBDongle-P, ZBDongle-E, Dongle-M, Dongle-PMG24, and Dongle-LMG21.
• Home Assistant and Zigbee2MQTT: Can be used directly with a compatible SONOFF Zigbee coordinator. For the full feature set, the manufacturer requires Zigbee2MQTT 2.12.1 or later.
• Home Assistant and ZHA: Can be used with ZHA integration, but according to the manufacturer's current documentation, a separate ZHA script is required for full functionality until native support is merged.
• Samsung SmartThings: Can be used with an Aeotec Smart Home Hub V3. The manufacturer provides a dedicated SmartThings driver.
• Amazon Alexa: Can be used with a compatible Alexa Zigbee hub. Supported functions include temperature and operating mode adjustment.
• Google Home: Temperature and operating mode control are supported.
• BLE: A separate BLE pairing mode is available. A device paired with a third-party Zigbee system can also be added to eWeLink via BLE without removing the existing Zigbee connection.

Smart Features

• Remote temperature adjustment: The target temperature can be adjusted between 5–30 °C.
• Automatic mode: The device controls the radiator according to the selected weekly schedule.
• Manual mode: The target temperature can be adjusted directly on the device or from the app.
• Frost protection mode: The radiator can be kept at a minimum temperature to help protect the room and heating system against freezing. The threshold can be adjusted.
• Boost mode: Starts maximum heating for a defined period, then returns to the previous operating mode.
• Temporary temperature override: A temporary target temperature can be set for a defined duration, after which the device returns to the previous mode.
• Temperature history: The eWeLink system stores temperature changes and heating activity for the previous six months.
• Automatic open-window detection: If the measured temperature drops by more than 1.5 °C within 5 minutes while heating, the device pauses heating.
• Door/window sensor-based control: Heating can be stopped immediately when a compatible door or window sensor detects an open state.
• External temperature sensor: A compatible SONOFF sensor linked to the eWeLink account can be selected as the reference temperature for control.
• Temperature hysteresis: The temperature deviation from the target at which the valve reopens can be configured.
• Temperature calibration: The measured value of the built-in temperature sensor can be corrected in software.
• Valve opening ratio: The valve opening and closing percentage can be configured separately.
• Adaptive control: When enabled, valve opening changes automatically based on the target and current temperature. In this mode, manual valve opening ratio and temperature hysteresis settings are disabled.
• Valve position at low battery level: The valve can be configured to close or remain 30% open when the battery level is low.
• Child lock: Disables local use of the rotary control while app-based control remains available.
• Push notifications: In the eWeLink system, notifications can be sent for low battery level and open-window detection.
• Group control: Multiple TRV-ZBT devices can be grouped and controlled together.
• Device sharing: Control of the device can be shared with other eWeLink accounts.
• OTA firmware update: Supported through eWeLink, Zigbee2MQTT, and a properly configured ZHA system.

Technical Specifications

• Product series: Thermo Series
• Product name: TRV Gen2
• Product type: Zigbee Thermostatic Radiator Valve
• Model: TRV-ZBT
• MCU: TLSR8258
• Input: 3 V DC, 2 × 1.5 V batteries
• Battery type: 1.5 V LR6 alkaline AA battery
• Zigbee: IEEE 802.15.4
• Valve thread: M30 × 1.5 mm
• Temperature setting range: 5–30 °C
• Net weight: 169 g, including batteries
• Operating temperature: -10 °C to +50 °C
• Operating humidity: 5–95% relative humidity, non-condensing
• Color: White
• Enclosure material: PC
• Dimensions: 50 × 50 × 82.9 mm
• Operating cycle life: 10,000 cycles
• Certifications: CE, RoHS

Additional Features

• 38% more compact design: The TRV Gen2 uses a smaller housing than the previous TRVZB generation.
• Rotatable display: The display can be rotated in 90° increments so it remains readable with different valve installation orientations.
• Direct M30 × 1.5 mm installation: Can be installed without an adapter on radiator valves with this thread size.
• Valve adapters: For other valve connections, one of the included adapters can be used if the valve is listed in the compatibility guide.
• Weekly valve movement: Every Monday at 12:00, the device automatically operates the valve to help reduce sticking and scale buildup.
• Low battery warning: The display warns when the batteries need replacement; the manufacturer recommends replacing them within one week after the low battery indication appears.
• BLE dual-platform use: A TRV operating in a third-party Zigbee system can also be added to the eWeLink app via BLE without removing the existing Zigbee connection or data.
• Unsupported Zigbee gateways: According to the manufacturer's documentation, the device is not compatible with Philips, IKEA, or Fritzbox Zigbee gateways.