LEFOO LF17 Heavy-Duty Air Compressor Pressure Switch
Heavy-duty mechanical compressor switch in the LEFOO LF17 family. The correct operating range, contact wiring and hydraulic or pneumatic installation depend on the ordered variant.
Model Identification & Key Specifications
Manufacturer Technical Data
LF17 manufacturer lists 40–250psi air operating and 140–175psi factory setting (35–60psi differential), plus 15–60psi alternative; LF17A is distinct 240–500psi (325–400psi factory setting), with 120VAC 30A/240VAC 25A versus basic LF17 24A/20A. The original CSA 1529896 dated 2007 names LF17 and LF17-W with 250psi maximum, so do not silently extend that certificate to LF17A 500psi variants.
AirAlign Engineering & Selection Analysis
A 500 psi listing for LF17A is not a licence to use 250 psi-rated LF17 or LF17-W at that pressure. The referenced 2007 CSA model record has explicit scope and must be matched to the actual nameplate and suffix.
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.
A maker-hosted CE, TÜV, UL or CSA record may cover only stated models and revisions. It is not equivalent to proof of ATEX/IECEx approval or a finished installation certificate.
LF17 vs LF17A: Do Not Mix Pressure Classes
LF17 includes more than one air-compressor operating class, and the separately specified LF17A is a higher-pressure model. These pressure and current differences determine interchangeability.
| Variant / class | Operating envelope | Representative factory setting | Contact rating |
|---|---|---|---|
| LF17, heavy-duty class | 40–250 psi | 140 / 175 psi (cut-in / cut-out) | 24 A at 120 VAC; 20 A at 240 VAC |
| LF17, low-pressure class | 15–60 psi | 30 / 45 psi | Confirm actual LF17 ordered assembly |
| LF17A | 240–500 psi | 325 / 400 psi | 30 A at 120 VAC; 25 A at 240 VAC |
LF17 has a painted-steel enclosure and optional unloader valve. Do not infer hazardous-location suitability or LF17A certificate coverage from approval documents naming only LF17 or LF17-W. Maker: official LEFOO LF17 / LF17A variant table.
Related Models & AirAlign Categories
LEFOO LF17-W Water Pump Switch · LEFOO LF15 Air Compressor 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.
LF17 — heavy-duty does not mean any motor
LF17 is marketed for heavy-duty compressor switching, but the application still requires matching motor start current, electrical utilization category, phase arrangement and air-tank pressure rating. Choose the cut-in/cutout band to avoid excessive start frequency, and confirm the unloader/bleed port option and thread. The related LF17-W water-pump product is a different service category; do not transfer air-unloader assumptions to water systems.