Siemens Maxum II PD PA AP Service Manual page 50

Valves
4.3 Model 50 Valve
8. Carefully remove the placement disc without moving the diaphragm. Inspect the diaphragm
for proper alignment. If the diaphragm is not in the center of the plate, repeat the placement
procedure using the placement disc.
9. Place the middle plate on the valve taking care to use the correct holes. Check the alignment
mark on the side of the plate. It should align with the mark on the bottom plate. If not, the
middle plate is upside down and must be removed, turned over, and reinstalled correctly.
10.Repeat steps 7 and 8 with the middle plate.
11.Place the top plate on the valve, verifying alignment using the alignment marks.
12.Install the 5 screws and washers finger tight.
13.Tighten the screws down evenly (2.5mm Allen wrench) to 6 to 8 inch-pounds of torque. (It
is recommended to use the torque wrench available from Siemens, PN 1631005-001, which
is calibrated at 7.2 inch pounds). Remove the assembled valve from the valve fixture.
Valve Cleaning
To clean the three valve plates use an Ultrasonic cleaner with clean acetone. If cleaning solvent
becomes contaminated during performance of the following steps, replace it with a clean
supply of cleaning solvent. Do not place polished valve plates against any surface in ultrasonic
cleaner or against any abrasive surface. Place parts on a lint free cloth, free of foreign
contaminants.
1. Fill Ultrasonic cleaner with cleaning solvent.
2. Before placing valve plates in Ultrasonic cleaner, wipe off all grease and foreign
contaminants from valve parts.
3. Place valve body parts on a lint free cloth in ultrasonic cleaner.
4. Turn Ultrasonic cleaner ON and allow to run for 10 minutes.
5. Remove parts and blow dry.
6. Inspect each port on all three plates carefully for material blocking ports. Check both vertical
and horizontal holes on center plate. (If needed use a 0.031" gage pin.)
7. Before reassembling valve, clean hands, tools and perform reassembling procedures in a
clean dust-free area.
50
Maxum II Valves and Oven Components
Service Manual, 10/2018, A5E42019844001