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Lefoo Pressure Switch HVAC

A pressure switch is a control device that runs a switch on or switch-off action when a preset pressure value occurs. LEFOO low pressure switches and high pressure switches are mainly used as the flow controller for fluid or gas in applications such as HVAC systems, water pumps, boilers, gas tanks. The Lefoo group was launched in 2000, Lefoo manufacture pressure switches for an extensive range of industries include -10000 pa to 10000 pa, and from 0~200 bar. Such as HVAC, refrigeration, air, compressor and pump pressure, automatic water pump, vacuum, steam, differential pressure, float, miniature and vacuum, high pressure, level, and digital switches and sensors to meet the utmost needs of industrial application and harsh environment. Each LEFOO pressure switch is high accuracy with numerous pressure ranges, flexible for any connections.
  • Digital Pressure Switch +
    Digital Pressure Switch

    Pressure Range:  -100~100kpa
    Pressure Accuracy: 1%FSO
    Work Temperature: 0~50 °C
    Measure media:  Non-corrosive dry gas
    Output: digital 4~20ma/1~5V, Swith NPN /PNP

  • Air Compressor Cut Off Switch +
    Air Compressor Cut Off Switch

    Pressure Range:  15~60psi / 40~250psi / 400~500 psi
    Stable and accurate pressure switching
    Rare metal parts, durable quality
    Optimal for heavy duty commercial air compressors
    Robust structure for industrial harsh conditions

  • Differential Pressure Switch +
    Differential Pressure Switch

    Various Pressure Ranges:  20pa~10000pa
    Robust plastic structure
    Capable highly customized
    Simple installation, easy to adjust
    Long service life,  accurate and stable

  • Water Pump Pressure Switch +
    Water Pump Pressure Switch

    Pressure Range:  1.5~12.5kgf/square cm
    Water-Resistant
    Long electrical serve life
    High-Pressure Accuracy Switching
    Various interfaces and connections

  • Pressure Gauge LFB +
    Pressure Gauge LFB

    Things you need to know about  LEFOO pressure gauge LFB series

  • LEFOO Mechanical Pressure Switch +
    LEFOO Mechanical Pressure Switch

    Range:  0.2~45Bar(LF08) / 0.5~250 Psi(LF20)

    Compact structure,Adjustable Pressure

    Good durability: Optional IP67 protection

    Multiple series, various connector wiring harness

    Suitable for most media and complex working sites


  • Water Controller +
    Water Controller

    Pressure Range: 1.5~10 Bar

    Max current:8A
    Compact size, Easy to install
    Stable and accurate performance, noiseless
    Energy-saving and environmental protection

  • Water Pressure Switch +
    Water Pressure Switch

    (LF42H)Cut in and off Pressure:   1.5bar / 2.5bar

    (LF42L) Cut in and off Pressure:  0.1 / 0.2 bar

    Good working stability
    Excellent durability and pressure resistance
    Water supply pressure control for the water purifier

  • HVAC Pressure Switch +
    HVAC Pressure Switch

    Pressure Range:  <16Bar~47Bar
    Adjustable Pressure Setting
    One-piece interface welded bellows element
    Fast rebound function, Low abrasion and Durable
    High reliability electrical & mechanical performance

  • Boiler Pressure Switch +
    Boiler Pressure Switch

    Pressure range:  5-50 psi
    Small hysteresis quantity
    For boiler system and oil pressure system
    316L steel diaphragm, capable of most media
    Transparent visual cover, adjustable pressure/scale

Lefoo Low Pressure Switch HVAC, Lefoo High Pressure Switch HVAC

A mechanical adjustable pressure switch applies a spring-triggered piston sealed by a diaphragm and rubber O ring. Generally, The spring is the opposing force to the inlet pressure and the spring's pretension is adjusted with a male stud screw by a female screwdriver. People preset a targeted high pressure on the male-threaded stud inside the pressure switch which is subjected to trigger the off switch, and a preset low-pressure value to trigger the switch. For example, in the hot pipeline of an HVAC system, when the compressed high-temperature high-pressure air comes and the pressure rises to an exact value which will trigger the off switch, the spring pretension directly correlates to the pressure at which the switch makes an electric contact. When the pressure drops, the switch resets to its original state and turns on the switch. The low-pressure switch and the high-pressure switch in the HVAC system are two types of basic refrigeration switches in a typical high-taste residential system.


The mechanical pressure switch is better suited for handling high voltages and amperages than an electronic pressure switch. They can be used to make a contact change for an increase or decrease in pressure.


Common Applications of the HVAC Pressure Switch 

HVAC,  air compressor blowers,  gas cylinders, air compressor cut off switch, generator sets, off-road vehicles, compressors, wafer ovens, process equipment, flow control devices, pumps, wastewater, heating and cooling systems, and numerous other applications from LEFOO pressure control across industries. 


Lefoo Electronic Pressure Switches

An electronic pressure switch is controlled by the charging signal generated from a pressure sensor, Which is proportional to the pressure. Thus, not only is it identified whether the defined switch point has been reached, but the actual measured pressure is transmitted. Electronic pressure switches often feature a display from which the measured pressure can be read, digital air pressure switch and switching buttons also offer adjustable settings. Switch points, pressure output signals can be individually adjusted to suit the remote monitor control application.


The pros of electronic pressure switches are precise measurement, intelligent remote controllable, The con is the price is much higher than mechanical pressure switch and not suitable for extremely high-temperature high-pressure measurement and applications.


Pressure: It must be able to withstand the maximum working pressure. A diaphragm design works well for vacuum and low-pressure applications. For high-pressure applications, use a piston design.


Temperature: It must be able to work well within its maximum and minimum temperature range.


Repeatability: Repeatability, or accuracy, is the ability of the device to accurately switch back to the same set point for every repetition. The range of accuracy required will determine the selection of the pressure switch for your application. Diaphragm designs generally provide more accuracy than piston designs.


Electronic pressure switches are suitable for automated and controlled equipment systems that require programmable function, digital display, flexibility, accuracy, ingress protection, and stability. Common media used with pressure switches are Hydraulic oil, Heating oil, Turpentine, Petrol/gasoline, Air. The automatic pump control switch for water pump applied to the water system will automatically start and stop the water pump according to the set pressure value.


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