Frequently asked questions

• Can I submerge the housing in water?

  No. IP65 means splash and light-jet protection — only the steel probe goes into liquid. The maker explicitly rules out submerging the body, pressure-washing it or leaving it in heavy rain without shelter.
• Does the SNZB-02LD measure humidity too?

  No — it is a pure thermometer: one value, the probe temperature. For room humidity pick the SNZB-02D with its display; outdoors, the IP65-rated SNZB-02WD.
• How do I fit it to a freezer, and what happens at −20 °C?

  Probe inside the chest, cable under the gasket, body outside. The tip handles −40 °C; leave the body itself at −20 °C, though, and deviation grows toward ±0.7 °C, the battery loses capacity and the screen starts ghosting.
• Which hub do alerts depend on?

  Any one from the official list: Zigbee Bridge Pro, Bridge Ultra, NSPanel Pro, iHost, ZBDongle-E/P (Home Assistant), Echo Plus 2nd / Echo 4th / Echo Show 2nd, or SmartThings V3 / Aeotec V3. The screen alone works without them.
• How long does the bundled CR2477 last?

  Up to 2 years by the maker's data; the real figure depends on how often the sensor reports. The level is always on the screen, the cover opens with a coin, and the cell is a CR2477 — not a CR2450.
• Can it switch the aquarium heater on by itself?

  By itself — no: the maker states the SNZB-02LD does not execute scenes, it only triggers them. The hub runs the rule: below the threshold it fires a ZBMINIR2 relay or a Zigbee plug feeding the heater.
• Can the readings be calibrated?

  Yes, within −40 to +115 °C. The offset is available on the newer eWeLink hubs (Bridge Pro, NSPanel Pro, iHost) and in Home Assistant; the old ZBBridge and Echo speakers do not offer it.
• Can I ask for the temperature by voice?

  Yes — via Alexa: either directly on an Echo with a built-in Zigbee hub, or by linking your SONOFF hub from eWeLink to the voice platform. The maker's own example: asking whether the bath water is ready.