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Lefoo Residual Pressure Transducer LFM208

LEFOO LFM208 residual pressure sensor is a high-precision product developed specifically for differential pressure control of smoke control systems in high-rise buildings. The core pressure measuring element adopts the US SM differential pressure chip. After zero, full scale and temperature compensation, the residual pressure sensor has high accuracy and good stability to fully meet the differential pressure control requirements of the positive pressure system, the product itself with green status indicator and red pressure alarm indicator. The product adopts 24 V DC power supply safety special low voltage power supply: using optional two bus way or 485 communication way, wiring simple, cost saving product appearance size is 86 * 86 * 38. This product is mainly for positive pressure air supply system elevator front room and stairwell special, product action pressure and reset pressure factory has been set before, the site does not need to set the site, greatly improve the control accuracy of the product, while greatly reducing the construction workload of the site is mainly used for elevator front room, shared front room, closed refuge, stairwell, smoke stairwell differential pressure measurement and control system; can also be used for indoor and outdoor differential pressure detection It can also be used in the differential pressure measurement and control system of dry gas such as filter blockage monitoring system.


* Adopt imported MEMS pressure sensor parts

* Support 86 boxes embedded installation

* Two kinds of communication methods can be selected

* Fully meet the national standard "Technical Specification for Building Smoke Prevention and Exhaust System"

* Pressure monitoring of elevator front rooms and stairwells of high-rise buildings, shopping malls, hospitals and other public places

Specification of Residual Pressure Transducer LFM208

Measurementrange 0~±100Pa
Accuracy (a)±1%F.S
Working temperature(-20℃~75℃
Compensated temperature(-5℃~60℃
Protection GradeIP30
Power Supply24VDC±2.4V
Trachea connection(+)High voltage side,(-)Low pressure side; adopt 3.5mm inner diameter hose
InstructionsGreen status, red alarm indicator
Display methodWith display/without display
Measured mediumAir and non-corrosive gas
Control signal(b)switching value
Communication modeTwo bus (two-wire system)/RS-485 (four-wire system)
Withstand voltage1000Pa

a) Accuracy is obtained by testing at room temperature 25℃; b) Connecting resistive load (optional)

How to Select

Code and description






Measurement range




without display

Screen display





Communication mode


P=Pb Two -bus





Model selection example

Note: For example, when LFM208-4050-DR is selected, the operating pressure of the residual pressure transmitter is 50Pa. The reset pressure is 40Pa. With screen display, RS485 communication output.

Function Description

The residual pressure transmitter panel has two indicators: a green status indicator and a pressure alarm indicator;

1. Status indicator: Under normal working condition, the green indicator light is on; under the equipment failure condition, the green indicator light flashes;

2. Alarm indicator: During pressure measurement, when the air pressure is lower than the reset pressure, the alarm light is always on. If the air pressure is higher than the operating pressure. The alarm light flashes. When the pressure is between the reset pressure and the operating pressure, the alarm light is off;

If the product has a pressure display window, the pressure value can be directly displayed;

LEFOO Function Description LFM208

Features of Residual Pressure Transducer LFM208

  • Adopt American imported pressure sensing element

  • Elevator front room and staircase of high-rise building

  • Basement and refuge

  • Pressure monitoring in hotels, shopping malls, hospitals and

  • other public places

  • Compliant with The National Standard

    《Technical Standard for Smoke Management System in Buildings》

Applications of Residual Pressure Transducer LFM208

Pressure monitoring for fire exits. And prevent the leakage of toxic gases and dense smoke when fire broke out.

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