The 20P7-75 Pressure Swichgage® with lockout, is a 2" dial, diaphragm-actuated pressure-indicating gage with a built-in electrical limit switch, which is used for tripping alarms and/or shutdown devices. This dual-scale instrument has a range of 0-75 psi (517 kPa) [5.0 bar].
The gage mechanism is enclosed in a steel case coated to resist corrosion. A polycarbonate, break-resistant lens and a polished, stainless steel bezel help protect this rugged instrument. Accuracy and protection from moderate overpressure is assured by a unique, unitized diaphragm chamber. A built-in pulsation dampener helps eliminate pointer flutter and is removable for cleaning.
On the 20P7-75, the low limit contact can be by-passed on start-up by pushing the lockout button. It holds the pointer away from the shutdown contact while the engine starts. The lockout will disengage automatically on rising pressure. Additionally, the gage pointer acts as a pressure indicator and as one switch pole which completes a circuit when it touches the adjustable limit contact. Contacts are grounded through the case and have a self-cleaning motion to ensure electrical continuity.
The 20P7-75 Pressure Swichgage® was specifically designed to protect engines and equipment in oil field, marine, irrigation, construction and trucking applications by monitoring engine lube pressure, water pump pressure, hydraulic pressure and air pressure. This popular instrument features a beryllium copper diaphragm, a 1/8-27 NPTM brass process connection, and exceeds SAE standards.
