Kromschroder Tightness control 84765820

Kromschroder tightness control 84765820 is a control box used for tightness testing of gas safety valves before every controlled startup or after every controlled shutdown in systems with two safety valves. It operates with a supply voltage of 220–240 V and has a storage temperature range of -15 to 40 °C. The device features screw terminals with a cross-section of 2.5 mm², a maximum switching current of 5 A, and an IP40 protection class. It is housed in impact-resistant plastic and weighs 0.485 kg. The test period is adjustable from 100 to 600 seconds, and it requires an external pressure switch for verification.

Parts of this type are selected by matching the supply voltage, test period range, and terminal specifications to the existing system. The device must be installed with proper cable glands (M16 plastic) and connected to an external pressure switch mounted between the valves. Ensure the ambient temperature and storage conditions are within specified limits. The housing has 5 knock-out holes for cable entry, and the unit should be mounted securely to avoid vibration.

Common failures include malfunction of the internal relay or fuse, leading to the burner not starting or shutting down unexpectedly. If the external pressure switch fails, the tightness test may not complete, causing a lockout. Check the fuse (5 A slow-acting) and the pressure switch connections. Also, verify that the test period setting is correct and that the device is not exposed to condensation or extreme temperatures.