remote-water-level-float
ITIAN Smart Tank Low-Level Alarm
Installation and Configuration Manual
Gateway + Zigbee Door Sensor + Float Switch
This beginner-friendly manual shows how to use your GW018 Smart Gateway and Zigbee magnetic door sensor as a low-water alarm for a tank.
Read This First
Never connect mains, 12 V, 24 V, pump voltage or any external power to the door-sensor contact points. The float switch must be a passive voltage-free dry contact.
The exact solder points cannot be confirmed until the sensor is opened. Identify the reed-switch terminals with a multimeter before soldering.
Use this smart alarm as an extra warning system. Do not make it the only pump dry-run or overflow protection.
1. Parts and Tools
GW018 Smart Gateway
5 V, 1 A gateway linking 2.4 GHz Wi-Fi to Zigbee devices.
Zigbee Door Sensor
Battery-powered open/closed magnetic sensor.
Float Switch
Two-wire dry-contact float switch for the tank.
Tools
Multimeter, small screwdriver, fine soldering iron, solder, heat-shrink, cable and waterproof box.
2. How the System Works
Float Switch→Door Sensor→Zigbee→GW018 Gateway→2.4 GHz Wi-Fi→Smart Life App
3. Test the Float Switch
- Disconnect the float from all other circuits.
- Set the multimeter to continuity.
- Connect the meter to the two float wires.
- Move the float to the normal-water position and record Open or Closed.
- Move it to the low-water position and record the opposite state.
| Position | Meter Result | Use |
|---|---|---|
| Normal water level | Open or Closed | Normal app state |
| Low water level | Opposite state | Alarm trigger |
4. Connection Methods
Method A — Magnet Method
Leave the sensor intact and use the float mechanism to move the supplied magnet toward or away from the sensor. This avoids soldering.
Method B — Direct Dry Contact
Open the sensor and connect the float switch across the reed-switch contact points. This is more compact but requires careful soldering.
5. Direct Wiring Diagram
ZIGBEE DOOR SENSOR PCB FLOAT SWITCH
Reed terminal A o-----------------------------o Wire 1
PASSIVE DRY CONTACT ONLY
Reed terminal B o-----------------------------o Wire 2
NO EXTERNAL VOLTAGE
6. Modify the Door Sensor
- Remove the batteries.
- Open the sensor carefully.
- Locate the glass reed switch or its two PCB solder pads.
- Use continuity mode and the supplied magnet to confirm the correct points.
- Solder one fine insulated wire to each reed terminal or pad.
- Route the wires through a protected exit hole and add strain relief.
- Connect them to the float cable in a sealed junction.
- Check for solder bridges, refit the batteries and test before closing.
Keep the supplied magnet away after modification, otherwise it may still operate the original reed switch.
7. Your Equipment
8. Pair the GW018 Gateway
- Install Smart Life or Tuya Smart.
- Sign in and connect the phone to 2.4 GHz Wi-Fi.
- Power the gateway from a stable 5 V, 1 A USB supply.
- Hold the gateway reset button for about five seconds until the indicator flashes.
- Tap Add Device in Smart Life.
- Select the discovered gateway or choose a Zigbee Gateway manually.
- Enter the 2.4 GHz Wi-Fi password.
- Name the gateway Tank Gateway.
9. Pair the Door Sensor
- Fit the correct batteries.
- Open Tank Gateway in Smart Life.
- Select Add Sub-device.
- Hold the door-sensor reset button for about five seconds.
- Confirm the LED flashes rapidly.
- Wait for discovery and name it Main Tank Low Level.
- Move the float and confirm the app changes between Open and Closed.
10. Create the Low-Level Alarm
- Open Scene or Smart in Smart Life.
- Create a new Automation.
- Under IF, choose Device Status Changes.
- Select Main Tank Low Level.
- Select the state that represents low water: Open or Closed.
- Under THEN, choose Send Notification.
- Use: ⚠ LOW WATER — Main tank has reached the low-level float. Check water supply and pump.
- Save and enable the automation.
Optional recovery automation: when the float returns to normal, send “✅ Main tank level restored above low-level float.”
11. Install the Float
- Choose the remaining water volume that should trigger the alarm.
- Mount the float at that physical height.
- Ensure it moves freely and cannot catch on a wall, pipe, ladder or cable.
- Keep the modified door sensor outside the tank in a dry weatherproof box.
- Pass only the float cable into the tank through a suitable gland.
- Add a drip loop and label the enclosure.
Do not place the door sensor or its batteries inside the wet tank environment.
12. Commissioning Test
13. Troubleshooting
| Problem | Likely Cause | Action |
|---|---|---|
| Gateway will not pair | 5 GHz Wi-Fi or incorrect reset | Use 2.4 GHz and repeat reset close to router. |
| Sensor not found | Not in Zigbee pairing mode | Add as sub-device and hold reset until rapid flashing. |
| App state never changes | Wrong solder points or float fault | Test continuity at every stage. |
| Alarm works backwards | Wrong Open/Closed trigger | Edit automation to the opposite state. |
| False alarms | Float bounce or loose wiring | Secure the float and wiring; add delay if supported. |
| Sensor offline | Weak Zigbee or low battery | Move gateway closer and replace batteries. |
14. Maintenance
| Interval | Task |
|---|---|
| Monthly | Operate the float and confirm the phone alarm. |
| 3 monthly | Inspect enclosure, cable gland and float movement. |
| 6 monthly | Check battery level and replace if low. |
| After router changes | Confirm gateway is online and retest. |