LEFOO LF20-V Factory-Set Vacuum Pressure Switch

LEFOO LF20V manufacturer product photograph — LEFOO LF20V · Official manufacturer image and specification

LEFOO LF20-V is a preset vacuum pressure switch. Correct selection depends on the actual switching range, process medium, terminal construction and the intended control/safety function.

LF20-VAirManufacturer model family

Model Identification & Specifications

ManufacturerLEFOO

ModelLF20-V

Device technologyPreset vacuum pressure switch

Process mediumAir

Manufacturer switching envelope1.1–22 inHg vacuum factory-set choices

Operating / proof limits30 inHg maximum vacuum working; 150 psi burst

Electrical signalResistive and inductive contacts carry different current limits

Order-code scopeManufacturer configuration sheet determines final claims

Important: Operating, proof and burst are not interchangeable limits. A published pressure class does not give every connector, material and switchpoint variant the same rating.

Verified Manufacturer Technical Notes

Original manufacturer lists 1.1–22 inHg vacuum switchpoint, 30 inHg maximum vacuum operating, 150psi burst; negative vacuum threshold is NOT a positive pressure setpoint. Four OEM setting bands 1.1–3 / 4–8 / 9–17 / 18–22 inHg have differing tolerances. Resistive DC contacts and inductive AC loads have distinctly lower permitted currents. Fluorosilicone diaphragm, air medium only and exact sealed Metri-Pack option must be checked.

Engineering Selection — AirAlign Analysis

inHg vacuum is a negative-pressure threshold, not an equivalent positive gauge switchpoint. The four setpoint bands have different tolerances; choose the correct band for the evacuation/restart requirement and check whether the Metri-Pack sealed connection is included.

For a control loop, choose the actual trip and reset behavior first. A mechanical contact can provide alarm, protection or run/stop control but does not output a continuously calibrated measurement. Check any fail-safe state, wiring to the final load, switching cycle frequency, differential setting and the process connection before replacing a physically similar part.

Installation, Wiring and Media Compatibility

Electrical interface

Check normally-open/closed wiring, the contact’s inductive versus resistive load, switching duty and whether the output is a low-current signal or suitable for direct equipment control.

Pressure boundaries

Choose the manufacturer-defined switchpoint and reset hysteresis, and verify the maximum admissible steady-state pressure separately from any short-duration proof or burst figure.

Wetted materials and fittings

Confirm gas/liquid approval, diaphragm compatibility, port size, connection thread and physical mounting orientation against the exact order code. Some products are intended only for non-hazardous gases.

Environmental and certification scope

IP grade and electrical approvals vary with connector and enclosure. Check the actual model suffix and connector or enclosure variant against the applicable manufacturer certificates.

Official Manufacturer Resources

LEFOO LF20-V manufacturer source / document

LF20-V — factory-set vacuum trip

LF20-V has a preset vacuum operating point, so choose the manufacturer pressure code for the process rather than assuming every version can be adjusted in the field. Determine whether the contact changes on deepening or releasing vacuum, and test with a controlled pressure source under realistic leakage conditions. Port materials and reset differential affect suitability for a vacuum pump. It is a switch, not a general proportional vacuum transducer.