Type 42-25 (and 42-20) self-operated differential pressure regulators are designed to work in large heating systems and general industrial applications. The differential pressure to be controlled is transmitted to the spring-loaded operating diaphragm in the actuator and converted into a positioning force to move the valve plug. The regulators control the differential pressure according to the adjusted set point.

The Type 42-25 is a differential pressure regulator for installation in a bypass pipe or short-circuit pipe with set point adjuster via external springs set. The valve opens when the differential pressure rises.