1. The water flow sensor is mainly composed of a plastic valve body, a water flow rotor assembly and a Hall sensor. The sealing ring is made of nitrile rubber from Japan, and the upper and lower force structure prevents water leakage. 2. It is installed at the water inlet end of the water heater to detect the water flow rate. When the water passes through the water flow rotor assembly, the Hall Elements is and sealed with potting glue to prevent water ingress and aging 3. The magnetic rotor rotates and the speed changes with the flow rate, and the Hall sensor outputs corresponding pulses 4. The signal is fed back to the controller, and the controller judges the size of the water flow and regulates it 5. The impeller is inlaid with a stainless steel shaft, which penetrates up and down to disperse stress points forever 1. The lowest rated working voltage: DC3.5 5V-12V 2. Maximum working current: 15 mA (DC 5V) 3. Operating voltage range: DC 5~18 V 4. Load capacity: 10 mA (DC 5V) 5. Operating temperature range: 80 Celsius 6. Operating humidity range: 35%~90%RH (no frosting state) 7. Allowable pressure resistance: water pressure below 1.75Mpa 8. Storage temperature: -25~+80 Celsius 9. Storage humidity: 25%~95%RH Lead wire : 1 Red IN to positive 2 Yellow OUT signal output line 3 Black GND connect to negative pole 4 Green R Temperature sensor Frequency: F=5.5*Q(L/Min)-3 Error: 2% Voltage: 3.5-24VDC, current cannot exceed 10mA, output 330 pulses after flowing one liter of water That is, frequency calculation = constant 5.5 * unit flow (L/min) * time (seconds) -3 Colour:White Material:ABS Size:58x34x26mm Package Contents: 2* Water Flow Sensor Only the above package content, other products are not included. Note: Light and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.