Kromschroder Diaphragm 74924641

This is a safety/compensating diaphragm for Kromschroder gas pressure regulators. It has a nominal diameter of 80 mm and is manufactured in Germany. It is a purely mechanical part made of perbunan (NBR) rubber, resistant to natural and liquefied gas. It is compatible with Kromschroder VGBF/VAR 80 /B, VGBF 80..40 /b, VAR 80 /b, GIK 80 /b, and the corresponding /B models. The warranty period is 1 year.

Parts of this type are selected by the valve series and model and the manufacturer's part number; they are not interchangeable between different valve families. Before ordering, verify that the old diaphragm matches the new one in outline, and ensure the valve body is clean. The diaphragm sits between the valve body and the cover, held in place by screws; replacing it does not normally require removing the valve from the gas line, but the gas supply must be shut off and isolated. After refitting, check for leaks and recalibrate the outlet pressure if the valve is servo-regulated.

Typical failure modes include fatigue, tearing, or loss of elasticity. Symptoms include unstable output pressure that floats or pulsates, poor modulation, or failure to close fully, leading to combustion instability. Check the diaphragm for cracks, deformation, or stiffness, and inspect the valve seating area for contaminants.