H3A-2SL is a series H3 explosion-proof differential pressure switch. It is a heavy duty, industrial unit with a unique new design that provides sensitivity to differential pressures as low as 10inches of water (254mm w.c.), yet handles total pressure of 1500psi (103bar). The Series H3 utilizes a rotary motion transfer shaft that prevents a change in total pressure from causing a set point shift. Typical applications include water flow proving with an orifice plate, differential pressure across chiller and liquid filter status.