OWON THS-317-ET – Zigbee Temperature Sensor external probe

Measure temperature where normal sensors can't reach

A smart thermometer on the wall measures air temperature, but how do you know if your underfloor heating is supplying water at the correct temperature? Is your swimming pool warm enough? Is your freezer's temperature off? Or when is your expensive heat pump not working properly?
The OWON THS-317-ET is a Zigbee 3.0 temperature sensor with an external probe of 2.5 meters or 20 meters that you place directly in liquids, pipes or spaces, while the Zigbee module remains safely outside the environment to be measured.

With a measuring range of -40°C to +200°C and an accuracy of ±0.5°C, the THS-317-ET (we sell the V2 version) is suitable for applications from the freezer to heating pipes. The sensor runs on 2 x AAA batteries and connects via Zigbee 3.0 – directly compatible with Home Assistant via ZHA and Zigbee2MQTT.

⚠️ Please note: this is the standard Zigbee version, not the Tuya version. There is also a THS-317-ET-TY (Tuya) variant that works with Tuya hubs (LIDL, WOOX, NOUS), but not with Zigbee2MQTT or ZHA. The THS-317-ET you buy here is exclusively suitable for standard Zigbee platforms such as Home Assistant.

✅ Key Features & Benefits

• Choice of 2.5 meter or 20 meter external probe – Also measures at greater distances in pipes, liquids and enclosed spaces while the Zigbee module remains safely outside
• Enormous measuring range: -40°C to +200°C – From freezer to heating pipe, swimming pool and industrial applications
• ±0.5°C accuracy – V2 version (from January 2024) with improved precision
• Zigbee 3.0 – IEEE 802.15.4 @ 2.4 GHz; works with any Zigbee 3.0 network
• Plug-and-play – Directly supported in Zigbee2MQTT and ZHA for Home Assistant
• Battery-powered – 2× AAA batteries; economical consumption for long life
• Battery status monitoring – Low battery level notification in your home automation platform
• Temperature calibration – Offset and precision adjustable via Zigbee2MQTT
• Compact size – 62 × 62 × 15.5 mm; fits discreetly on a wall or in a cabinet
• 100 meter range – In open space; 30 meters indoors

🔌 Compatibility

🏠 Practical Example: Automatic Pool Temperature Monitoring

1. Mount the OWON THS-317-ET next to the swimming pool (not saltwater) and run the probe (2.5 m or 20 m) into the water, sealing the probe for prolonged submersion.
2. Home Assistant continuously receives the water temperature via Zigbee2MQTT.
3. Set up an automation: a notification on your phone if the temperature drops below 22°C.
4. Connect a smart switch to the heat pump: automatically turn on if the temperature is too low, turn off at 26°C.
5. Check the pool temperature from anywhere in the world via the Home Assistant app.

⚙️ Technical Specifications

⚠️ Points of Attention

• Not the Tuya version – The THS-317-ET does not work with Tuya hubs (LIDL, WOOX, NOUS). Choose the THS-317-ET-TY for Tuya platforms
• Not suitable for salt water – The probe should not be used in saltwater pools or other saline liquids
• Seal when submerged – For prolonged submersion in liquids, it is strongly recommended to seal the probe
• Not compatible with Aqara hub – Does not work with the Aqara ecosystem
• Temperature only – no humidity – Choose the THS-317 for air temperature and humidity measurement
• Range dependent on environment – Walls and obstacles reduce the range from 100m to approximately 30m indoors

❓ Frequently Asked Questions (FAQ)

What is the difference between the THS-317-ET and the THS-317?

The THS-317-ET has an external probe of 2.5 meters or 20 meters for measuring in liquids and pipes. The standard THS-317 measures air temperature and humidity via a built-in sensor, without an external probe.

What is the difference between the THS-317-ET and the THS-317-ET-TY?

The THS-317-ET-TY is the Tuya version for Tuya hubs. This product (THS-317-ET) is the standard Zigbee version for Home Assistant, Zigbee2MQTT and ZHA. They are not interchangeable.

Can I use the probe in my swimming pool?

Yes, but only in swimming pools without salt. For prolonged submersion, seal the probe. The probe should not be used in saltwater.

Can I calibrate the measured temperature?

Yes. Via Zigbee2MQTT, you can set a temperature_calibration offset and adjust the temperature_precision for the desired number of decimal places.

How quickly does the sensor report new values?

The reporting interval is adjustable between 1 and 5 minutes.

How long do the batteries last?

OWON designs the THS-317-ET for ultra-low power consumption for long battery life. The sensor automatically reports a low battery level via Zigbee2MQTT or ZHA.

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