The System Sensor WFD40EXP is a 4-inch explosion-proof waterflow detector for hazardous locations. It installs on 4-inch steel pipe, Schedule 10 through 40, in wet-pipe sprinkler systems. The vane-type switch reports water flow to the fire alarm panel. As a result, sprinkler discharge triggers an immediate alarm.
Hazardous Location Ratings
This detector is built for explosive atmospheres. Specifically, it is rated for Class I, Divisions 1 and 2, Groups B, C, and D. It also covers Class II, Divisions 1 and 2, Groups E, F, and G. Furthermore, Class III, Divisions 1 and 2 are included. The sensitivity spring is housed outside the explosion environment.
System Sensor WFD40EXP Specifications
- Pipe size: 4-inch steel pipe, Schedule 10–40 (2 in hole)
- Maximum static pressure: 450 psi
- Flow trigger threshold: 4 to 10 GPM; 18 FPS maximum surge
- Contacts: two synchronized SPDT (Form C); 10 A at 125/250 VAC; 2.5 A at 24 VDC
- Retard: sealed pneumatic delay, field-adjustable; replacement part A3008-0
- Operating temperature: 32°F to 120°F
- Enclosure: NEMA 4 cast aluminum, indoor or outdoor; weight 11.5 lb
Listings include UL (E200116), CSFM 7770-1653:145, and FM (3006195). However, use it on wet-pipe systems only — not dry-pipe, deluge, or preaction. Copper pipe is not permitted. Need a different pipe size? Alternatively, the WFD20EXP covers 2-inch pipe and the WFD35EXP covers 3-1/2-inch pipe.
For more information, contact the Life Safety Consultants team at (888) 557-0558, or email us at: sales@lifesafetycom.com
Additional information
| Weight | 14 lbs |
|---|---|
| Dimensions | 15 × 10 × 10 in |
| Condition | New |
| Manufacturers | System Sensor |
| Part Type | Sensor |







