LEFOO LF18 Three-Phase Compressor and Water Pump Pressure Switch
Three-phase pump/compressor switching in the LEFOO LF18 family. The correct operating range, contact wiring and hydraulic or pneumatic installation depend on the ordered variant.
Model Identification & Key Specifications
Manufacturer Technical Data
Three-phase NC compressor switch has four listed operating bands 1–5, 2–8, 3–11 and 4–16 bar with matching differentials 1–3, 1–3, 1.4–4 and 1.8–4.5bar. Listed 400VAC three-phase 16A/25A must be verified against the ordered contact configuration; optional unloader avoids restarting an air compressor against residual head pressure. Mechanical high/low cut-in thresholds are not analog sensing outputs.
AirAlign Engineering & Selection Analysis
Four operating bands have different cut-in/cut-out differentials: choosing the widest pressure span does not prove the same contact ratings or accessories. Unloader tubing applies to compressor duty and cannot be assumed necessary for every water-pump assembly.
Correct system operation is determined by the restart threshold, stop threshold, motor electrical duty and the available pressure supply. An adjustment range does not imply every combination is approved: compare manufacturer-specified differential, pressure proof, operating medium and fitting. For motor-driven equipment, locked-rotor conditions, overload protection and cycling frequency are separately important even where a contact-current rating is published.
Installation, Compatibility & Protection
Specify both cut-in and cut-out conditions for the intended equipment, and verify the manufacturer’s permitted hysteresis. Do not use proof or burst pressures as running thresholds.
NO and NC contacts have different protection and restart behavior. Match the wiring schedule and motor/contactor duty, rather than relying only on voltage and ampere numbers.
Verify actual air versus water compatibility, wetted materials, connection thread standard, sealing method and temperature of the process. The manufacturer variant must support the full application.
Manufacturer certificates and conformity documents should be interpreted only for the models and revisions explicitly covered.
LF18 Three-Phase Ordering Range Comparison
LF18 combines three-phase motor switching with an adjustable tank-pressure operating function. The OEM parameter table lists Air as the medium; despite the broader compressor/water-pump product-family name, determine wetted-material and water-system suitability for a particular LF18 order code before use with water.
| Available operating class | Published factory cut-in / cut-out | Listed differential |
|---|---|---|
| 1–5 bar | 2 / 4 bar | 1–3 bar |
| 2–8 bar | 3.8 / 5.0 bar | 1–3 bar |
| 3–11 bar | 5.6 / 7.0 bar | 1.4–4.0 bar |
| 4–16 bar | 8.0 / 10.0 bar | 1.8–4.5 bar |
Evidence: LEFOO LF18 option tables and documentation. Compare LF12 for different thermal-relay and wiring choices.
Related Models & AirAlign Categories
LEFOO LF12 Three-Phase Compressor Switch · LEFOO LF19 Compressor / Pump Switch · Pressure Switches · LEFOO manufacturer profile
Official Manufacturer Sources
Original maker catalogue evidence used for the model values above. Review the latest datasheet, ordering chart and approval scope for the specific suffix.
LF18 — three-phase pump and compressor differences
LF18 is listed for three-phase compressor/water-pump duty, but those services have different media and motor restart behavior. Select the actual wetted diaphragm, tank piping and pressure range for air or water, and coordinate contacts with the proper rated motor starter/overload. Compressor unloading may be required for air service but not equivalent for a water pump. A three-phase switching label is not a guarantee that all motor currents can pass through the pressure control directly.