Kromschroder Differential pressure switch DG500U-3 84447550

The Kromschroder DG500U-3 is a diaphragm pressure switch with a pressure range of 100–500 mbar. It monitors pressure changes in gases or air, switching a microswitch contact when the setpoint is reached. The trigger level is adjusted via a handwheel. The device features a glass fibre reinforced PBT plastic housing with an AlSi 12 lower section, an NBR diaphragm, and is silicone-free. It has an IP 65 protection class and a safety class of 1, with an M16 x 1.5 line entrance thread.

When selecting a replacement pressure switch of this type, ensure the pressure range, switching function (rising or falling pressure), and electrical connection (screw terminals, cable gland size) match the original. The mounting orientation and process connection thread must also be compatible. Verify the medium compatibility and temperature limits for the application.

Common failure modes include diaphragm rupture or leakage, leading to loss of pressure sensing or false switching. The switch may fail to trigger at the setpoint or stick in one position. Check for leaks around the diaphragm and housing, and verify the microswitch operation with a multimeter.