Definox Automatic Changeover Valve DN 4’’ US

Ensure the actuator configuration is correct (NC, NO, or DA)

Lubricate all parts with appropriate lubricant

Center the piston using the guide pin on the actuator stem

Fit the lantern seal [18] [18b] carefully using the press

Position the snap-ring (16) properly in the recess of the body before releasing pressure

Ensure the air supply is closed and the circuit is purged before starting work on the signalling box.

Ensure the mains supply is switched off before starting work on the signalling box.

Disassembling the Signalling Box

Refer to maintenance notices for fitting and removing the control top

Disassembling the DCX3 Valve Clamp Collar

Supply air to the NC actuator to relieve the pressure on the clamp collar from the spring.

Switch off the actuator air supply.

Use medium thread lock compound to lock the plug during reassembly on the actuator

Retighten the plug of diaphragm valves after first usage with temperature

Supply air to the actuator before tightening the clamp collars

Is the valve operating normally?

Describe any difficulties encountered during operations

Refit the stem/piston and spring assembly the other way around in the body

Check that the snap-ring is properly positioned in its recess

Is the snap-ring damaged or deformed?

Check for possible movement of the actuator body during the opening/close operation for DCX4 NO

Remove the defective seal using a cutter without marking the bearing surface of the plug.

Protect the stainless steel surface using the edge of a steel rule or a plastic off-cut.

Set oven temperature to 140°C (+/- 3%).

Place the new seals in the oven for 30 minutes.

Ensure the oven temperature does not exceed 200°C.

Verify the temperature is not too low to avoid seal deformation or tearing during installation.