System Sensor WFD40N 4″ Fire Sprinkler Water Flow Switch – UL/FM, NEMA 4, 450 PSI nhw-160se Compatible with gas-powered appliances like

Compatible with gas-powered appliances like Navien units

corrosion-resistant build for long-term use

✅ Applications:

including tankless water heaters

System Sensor WFD40N 4″ Fire Sprinkler Water Flow Switch – UL/FM, NEMA 4, 450 PSI nhw-160se Compatible with gas-powered appliances likeWFD40N 4 Fire Sprinkler Water Flow Switch UL FM Listed The System Sensor WFD40N is a 4 inch vane type water flow switch designed to monitor flow in wet pipe fire sprinkler systems. Engineered for dependable performance in demanding conditions, this switch is UL Listed, FM Approved, and housed in a NEMA 4 weatherproof enclosure for indoor or outdoor installations. Top Features: Fits 4 Schedule 740 steel pipe UL Listed and FM Approved 450 PSI maximum