Continuous Liquid Level (interface) Measurement and Automatic Control. Explosion-proof and water proof.

SI-U03 Float Switch Water Level Controller

Float Switch Water Level Controller Features

  • Three installation modes.
  • Suitable for various tank installations.
  • Suitable for viscous dirty media
  • High temperature resistance.
  • HART communication
  • Explosion-proof and non-explosion-proof available

Please feel free to contact us for Techinical Support, or Request a quote for float level sensors (customization available).

SI-U03 Float Switch Water Level Controller

Features of SI-U03 Float Switch Water Level Controller

Float switch water level controller is a continuous liquid level sensor & controller. Float switches, also known as float level switches. Float Switch Water Level Controller is mechanical water level indicators that depend on moving parts to trigger a switch.

Float switch water level controller can be directly installed on various tank equipment (water tank). Float switch water level controller is especially suitable for hot heavy oil in oil refinery (temperature ≤500 ℃, pressure ≤4.0MPa). Viscous and dirty media, asphalt, grease and other oil products. As well as flammable, explosive, corrosive and other media’s Liquid level (interface) continuous measurement and automatic control.

Specifications of SI-U03 Float Switch Water Level Controller

  1. Power supply voltage: 12 ~ 32V DC
  2. Output signal: 4 ~ 20mA, with HART communication protocol
  3. Flange specifications: Factory default HG20595-97 DN250 PN4.0 (can also be manufactured according to user requirements)
  4. Ambient temperature: -40 ~ 80 ℃
  5. Medium temperature: -40 ~ 500 ℃
  6. Live display: pointer indication + LCD display
  7. Display direction: left or right (factory default: left); left and right adjustable
  8. Accuracy level: 1.5% FS
  9. Adjustable damping: 0 ~ 32 seconds
  10. Explosion-proof grade: ExiaⅡCT2 ~ T6, ExdⅡCT2 ~ T6
  11. Fault diagnosis and alarm: Yes
  12. Load resistance: 500Ω (with 24V power supply)
  13. Floating ball diameter: φ240mm
  14. Float ball material: 316L
  15. Debugging method: On-site debugging, on-site magnetic control switch; debugging software + PC; handheld device
  16. Medium density: action limit density ≥0.50g / cm3
  17. Electrical interface: 2 NPT1 / 2
  18. Protection level: IP66

Types of SI-U03 Float Switch Water Level Controller

Protection leveldIIBT4dIIBT4dIIBT4
Pressure1.0 MPa1.0 MPa1.0 MPa
High Temperature:≤350℃
Net weight1.5~2.0Kg
Switching difference(mm)≤825~5508~1000
Setting methodNot adjustable Stepwise adjustableStepless adjustable
Installation formHorizontalHorizontalVertical
Power supply and contact capacity and lifeAC:220V/1.5A、110V/2.5A
Types of SI-U03 Float Switch Water Level Controller

Know more about: Guide for Liquid level float switches

How to install float switch in water storage tank?

A and B installation diagram
Type C installation diagram
  1. The flange of SI-U03 series electric float liquid level transmitter is installed on the side wall of the medium tank.
  2. Before installation, it should be considered in combination with the structural characteristics of the transmitter. It is convenient to operate, observe and maintain to determine the installation position and direction. If the floating ball transmitter is installed on the left side of the flange, it is installed on the left side, otherwise it is installed on the right side.
  3. Assume that the current state is the right installation. If you want to change to the left installation, use the HART Communicator to move or set the transmitter’s zero position and range.
  4. And (PV range), follow the prompts on the HART communicator display to enter URV (upper range value). LRV (lower range value). And display USL (upper sensor limit)With LSL (Low Sensor Limit). Reset the lower range value corresponding to 4mA and the upper value corresponding to 20mA and send it. If other parameters are not changed, you can change to the left installation.
  5. Floating ball and club installation: First, the floating ball and the club are tightened and welded. For the club installation operation of the new connection structure of SI-U03-A small-angle floating ball liquid level transmitter, the club is installed. Screw into the inner screw hole of the connecting rod at the end of the protective rod sleeve.
  6. Pay attention to tighten the top wires on both sides of the connecting rod into the annular grooves on the club. And then tighten the lock nuts on the top wire. For SI-U03-B large-angle floating ball liquid level transmitter, screw the ball into the inner screw hole at the end of the swing arm. And then tighten the top wire and lock nut on it in the same way.
  7. Note: “If the site conditions are poor, in order to prevent the floating ball, club, swing arm and other connecting parts from loosening. It is recommended to place the top wire and the lock nut on the joint and tighten the float and the club After welding directly to the coupling. “
  8. The transmitter is directly installed on the flange of the side wall of the medium container under test through a flange. The requirements for the straight pipe section of the connection flange are as follows: SI-U03-A L ≤ 160mm;
  9. The transmitter head is connected to the radiator through the connection plate. When installing, insert the spindle head into the coupling hole of the transmitter head, and the coupling should not be distorted. The meter head can be installed on the left or right side.
  10. For correct installation, please refer to the indicator dial on the back of the transmitter case. If the transmitter is installed on the left, turn the end pointer behind the meter head to the “left 0” scale. If the transmitter is installed on the right side, turn the pointer on the back of the meter to the “right 0” scale line. And when the float is moved to the lowest measurement position, tighten the set screw of the coupling and the spindle.
  11. Install the balance rod (mechanism) into the dental insert and square hole. Tighten the top wire to fix the balance rod. Loosen the shaft nut and adjust the dental insert to make the balance rod and the ball in the same plane. And put the axial head nut.
  12. Tighten the position of the balance weight and adjust the balance weight to the optimal state to fix the balance weight. Note: “For liquids of different densities due to the different buoyancy forces experienced by the float, the balance can be adjusted. The position of the hammer on the balance bar to achieve the goal of normal measurement. “
  13. In the process of adjusting the balance weight, when the feel is light, you can adjust the two M10 compression bolts of the waist-shaped compression sleeve inside the radiator to tighten the expansion force of the sealing gasket. Otherwise, you can adjust the waist-shaped compression sleeve when the feel is light Two M10 bolts loosen the expansion of the gasket until it does not leak!

How does a float level switch work?

The float ball level switch structure is mainly designed and produced based on the principles of buoyancy and static magnetic fields. The position of the floating ball with a magnet (floating ball for short) in the measured medium is affected by buoyancy. The change of the liquid level causes the position of the magnetic float to change. The magnet in the float and the sensor (reed switch) function to generate a switching signal.

Similar to the principle of the float level sensor. But the float level sensor outputs a quasi-continuous electrical signal, while the float level switch outputs a discrete switching signal.

Continuous Float Level Sensors


Liquid level controller refers to the control of high and low liquid level by mechanical or electronic methods. It can control solenoid valves, water pumps, etc. to achieve semi-automatic or full automation. There are many methods, depending on the choice of different products different.

Extended reading: Capacitive water level sensor

Notes on installation and adjustment of float level switch:

The float level switch only needs to re-calibrate the water level line before we install it. The switch itself cannot be adjusted. At this time, use a multimeter to measure the switch state. It will be turned on and off with the water level near the water line, which means that there is no problem.

Just make sure that the water level line of the thermal equipment is consistent during the installation. For example, the liquid level switch of SOR is usually attached to the water level line on the wall of the cylinder. We soak the switch in the water tank and slowly sink to make the water surface gradually approach the marking line. When you get closest, you will hear the micro switch the sound of.

Note that:
High-temperature liquid level switches, etc. have high operating temperatures and high water temperatures. The density of hot water is lower than the density of room temperature water, so the action line of room temperature water is lower than the switch marking line. Low level alarm is connected to normally closed (NC), high level is connected to normally open (NO). This type of switch is not difficult to install. The liquid level switch itself will have more than two pairs of micro-switches, which respectively output two pairs of normally open and two pairs of normally closed contacts, which are usually “on alarm” when applied.

Water level float switch is generally used for high level water tank water supply and sewage tank drainage. The device that converts the water level signal into an electrical signal to control the start and stop of the pump is called a water (liquid) level controller. Common water (liquid) level controllers include:Reed switch water level controllers. Float magnetic switch liquid level controllers. Electrode type water level controllers. Pressure type water level controllers, etc.

The price of the water level float switch is mainly determined by some parameters:
structure type;
Wetted material
Pressure Level;
Flange specifications
Explosion-proof type
Measuring range;
Insertion length
Medium density
Other contents such as density, operating temperature, operating pressure, electrical interface, etc., must be specified in the specification so that we can use them as reference data when designing the output.

Technical Support

Sino-Instrument offers over 10 level transmitters for level measurement.

About 50% of these are liquid level meters,

40% is the tank level sensor.

A wide variety of level meters options are available to you,

such as free samples, paid samples.

Sino-Instrument is a globally recognized supplier and manufacturer of level measurement instrumentation, located in China.

Request a Quote

Please provide your measurement parameters or details. Sino-Instrument support customer customization and OEM

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