Explosion Proof Waterflow Detector

The WFDEXP series is designed to handle extreme conditions.

Robust Construction. The WFDEXP series consists of a rugged, NEMA 4-rated cast aluminum housing. Designed for both indoor and outdoor use, the WFDEXP series operates across a wide temperature range, from 32°F to 160°F. Inside, two sets of SPDT (Form C) synchronized switches are enclosed in a rugged terminal block to assure reliable performance.

Reliable Performance. The WFDEXP series offers unique features that assure greater operational reliability. By housing the spring mechanism separately from the explosion environment, the sensitivity of the adjustment spring and the detector is protected at all times. Adding to WFDEXP’s reliability is its sealed retard mechanism, which prevents contamination by dust and dirt when the cover is removed.

Simplified Operation. Like all Safe Signal waterflow detectors, the WFDEXP series is designed for easy installation. With its visible switch activation, the WFDEXP’s retard timing can be verified, even during noisy conditions.


  • New WFD30-2EXP models install in 2˝ hole sizes
  • Designed and approved to operate in hazardous locations
  • NEMA 4 enclosure rating
  • Sensitivity-setting spring mechanism located outside of explosion environment
  • Sealed retard mechanism
  • Visual switch activation
  • Synchronized activation circuit
  • Field-replaceable terminal block and retard mechanism
  • Only one conduit entrance required for hook-up

These units are ideal for installation in hazardous locations classified as follows:

Class I, Groups B, C, D, Division 1 & 2

Class II, Groups E, F, G, Division 1 & 2 Class III, Division 1 & 2


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