Kromschroder Gas pressure regulator GDJ 25R04-0L 03155033

This spring-loaded gas pressure regulator is designed for gas trains of burners and boilers. It reduces inlet pressure up to 400 mbar to a stable outlet pressure adjustable from 5 to 160 mbar, with a standard factory setting of 12.5–25 mbar. The regulator features inlet pressure compensation via a separate compensation diaphragm, which maintains accurate outlet pressure despite fluctuations in inlet pressure. It provides zero closure, meaning the valve shuts off tightly when downstream pressure exceeds set point. The connection is internal thread Rp 1" (nominal diameter 25 mm), and the ambient temperature range is –20 to +60 °C. It has a turndown ratio of 10:1.

Gas pressure regulators of this type are selected by inlet pressure range, adjustable outlet pressure range, flow capacity, connection size, and gas type. Before ordering, match the connection thread and nominal diameter to the existing pipework, and verify that the outlet pressure range covers the burner's required setting. Also confirm the regulator is suitable for the gas used (natural gas, LPG, or dry air). During installation, follow the manufacturer's orientation (usually with the diaphragm housing upright) and ensure the supply pressure does not exceed the maximum inlet rating. After installation, test for gas-tightness and verify the outlet pressure with a manometer during operation.

A worn or damaged diaphragm typically results in outlet pressure drift, so the burner may surge or fluctuate. An incorrect spring tension can cause the outlet pressure to deviate from the set point. Check the diaphragm condition and spring tension during inspection, and always test for gas-tightness after any service.