Kromschroder Gas pressure switch DG500B-3 84447450

The Kromschroder DG500B-3 is a diaphragm pressure switch designed to monitor gas or air pressure, responding to rising or falling pressure. It has an adjusting range of 100–500 mbar and is suitable for natural gas, town gas, LPG (gaseous), flue gas, biogas (max. 0.1% by vol. H2S), and air. The switch features a glass fibre reinforced PBT plastic housing with a lower housing section of AlSi 12, and is silicone-free with low gas release. It operates within a medium and ambient temperature range of -20 to +80 °C, with a storage temperature of -20 to +40 °C. The device is IP54 rated, has a safety class of 1, and weighs 0.321 kg. It is certified to EN 1854:2010 and carries type designation CE-0085AP0467.

When selecting a replacement pressure switch of this type, verify the adjusting range, connection thread (M16 x 1.5), and electrical connection (screw terminals) match the existing installation. Ensure the line diameter (0.5–1.8 mm) and cable clamping range (up to 4 mm) are compatible with your wiring. Check the medium and ambient temperature limits, as well as the protection class (IP54), to suit the environment. The switch is designed for rising positive pressure; confirm the pressure monitoring direction required.

Common failure modes for diaphragm pressure switches include diaphragm rupture or leakage, leading to loss of pressure sensing and improper burner operation. Symptoms may include the burner failing to start, intermittent shutdowns, or the system not responding to pressure changes. Check for gas leaks around the switch, verify the diaphragm integrity, and test the switch function with a manometer to ensure it actuates at the set point.