Kromschroder Gas pressure switch DG500H-3 84447660

The Kromschroder DG500H-3 gas pressure switch, SKU 84447660, is a mechanical diaphragm pressure switch designed for monitoring gas or air pressure in boiler systems. It has an adjusting range of 1000–500 mbar and switches with rising pressure. The switch is silicone-free and features a glass fibre reinforced PBT plastic housing with a lower housing made of AlSi 12, and an NBR diaphragm. It operates within a maximum medium and ambient temperature range of -15 to 60 °C, has a protection class of IP54, and weighs 321 g. Connection is via screw terminals with an M16 x 1.5 line entrance thread and a cable clamping range of 4 mm.

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 existing setup. Verify the medium compatibility (gas or air) and that the switch is silicone-free if required. Check the ambient temperature range and protection class (IP54) to suit the installation environment. The switch should be mounted with the diaphragm in the correct orientation and wired according to the manufacturer's instructions.

Common failures of this type of pressure switch include diaphragm rupture or leakage, which can cause the switch to fail to detect pressure changes, leading to boiler shutdown or erratic operation. Silicone contamination can also occur if the diaphragm is not silicone-free, affecting performance. Symptoms may include the boiler not starting, frequent lockouts, or pressure readings that do not match the setpoint. Check the diaphragm for damage, verify the switch operation with a manometer, and ensure the electrical contacts are clean and properly adjusted.