Kromschroder Gas pressure switch DG50UG-4 84447020

The Kromschroder DG50UG-4 gas pressure switch (SKU 84447020) is a diaphragm-type pressure switch designed to monitor pressure fluctuations in gas or air systems. It operates with rising positive pressure for gas/air, negative pressure for air, and differential pressure for air-air applications. The switch features gold-plated contacts, screw terminals, and an M16 x 1.5 cable gland, with an ingress protection rating of IP65. Its pressure range is 2.5 to 50 mbar, and it is suitable for media such as natural gas, town gas, LPG (gaseous), flue gas, biogas (max. 0.1% by vol. H2S), and air. The housing is made of glass fibre reinforced PBT plastic with a lower housing section of AlSi 12, and the diaphragm is NBR, silicone-free. The switch complies with EN 13611 and EN 1854 standards and has a net weight of 0.321 kg.

When selecting a replacement pressure switch of this type, ensure the pressure range, connection thread (M16 x 1.5), and electrical connection (screw terminals) match the original. Verify the switching function (rising or falling pressure) and the medium compatibility (e.g., gas type, temperature range). The cable clamping range must accommodate the existing cable diameter (4 to 10 mm). Mounting orientation and process connection must also be compatible with the existing installation.

Common failure modes for diaphragm pressure switches include diaphragm rupture or leakage, leading to loss of pressure sensing or false switching. Symptoms may include burner lockout, erratic operation, or failure to detect pressure changes. Check for visible damage to the diaphragm, proper sealing, and correct setpoint adjustment. Also inspect for contamination or corrosion of contacts, which can cause intermittent electrical faults.