FLK Gas Sampling System - MPIP - Free

SQ253 Valve Combination
4.3.1 Replacing the valves
• Pull off the cable head after loosening the screw.
• Loosen screwed joints on the housing.
• Unscrew the pipes at both ends.
• Before fitting the new valve
Note:
Pay attention to voltage and type of current according to the nameplate.
• Clean the pipe work of contamination (metal swarf, sealing material).
Note: The arrow indicates the direction of flow. Do not use the valve as a lever when screwing it in. Do not block pilot hole
on the valve output with pipe ends, sealing material, etc. Use PTFE tape as sealing material.
• Assembly takes place in the reverse sequence.
4.3.2 Cleaning the valve
• Pull off the cable head after loosening the screw.
• The pilot valve can be removed after loosening the four screws on the solenoid section.
• Take care with the core and spring.
• Loosen four screws on the valve cover.
• Remove the upper part.
• Take out the diagram and, if necessary, clean it and replace damaged parts.
• The valve body can now be cleaned.
• Grease with silicone grease or acid-free Vaseline.
• Assembly takes place in reverse sequence.
Note:
Observe the tightening torque of 1Nm for the cable head.
4.3.3 Faults:
• Check connections. operating pressure and voltage.
• Pilot hole on the valve output covered or contaminated ?
Solenoid does not pull in:
• Short circuit or coil interruption.
• Core or core aperture contaminated.
• With alternating current, jammed core causes coil overheating.
Leaky valve:
• Procedure as under Section 4.3.2
SQ253 Valve Combination
Copyright ® SIEMENS Page 69 04/04