Mid-West Instrument’s Model 522 differential-pressure/indicator switch is a diaphragm-type unit that features complete high-to-low side isolation, making it a good fit for low-flow monitoring of heat exchangers in geothermal applications. The switch features a max. static pressure of 1,000 PSIG (69 bar), a max differential over-range pressure of 200 PSID (13.89 bar) and differential-pressure ranges of zero to five and zero to 50 PSID with +/- 5 percent full scale accuracy. Body materials are aluminum or 316/316L stainless steel with 316 SS, ceramic and acetal moving parts. The 522 unit is available with one or two field adjustable (40 percent to 100 percent full scale) hermetically sealed reed switches in SPST (3 amp) configuration. Features up to 240 VAC/VDC voltage ratings, flying leads, or DIN-type connectors and can be custom-designed to meet mounting requirements or operating conditions. Dial accuracy +/-5 percent standard with a five-year warranty.