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Servicing
Vacuum Pump Diaphragm and Valve Replacement
Valve Replacement
7-22
42iQHL Instruction Manual
Use the following procedure to replace the valve.
1. With the head off the pump, unscrew the socket head cap screws with
M4 lock washers ("S") to remove the head lid ("T") and gasket ("V").
2. Loosen the single pan head screw, washers and nut ("P") and remove
the two stainless steel reed valves ("Q"). If necessary, hold the nut in
place with a nut-driver.
3. Lightly clean the valve seat area of debris or deposits with fine-grade
steel wool. This area must be clean and smooth, without pits or
scratches. Do not scratch the head plate. Finish the cleaning with
alcohol and then air-dry the parts.
4. Lay the two replacement reed valves on a flat surface to the direction of
any slight bend.
5. Lay the replacement reed valves in place, center bowed out (see valve
installation), and tighten the pan head screw, both washers, and the
nut. Be certain that the reed valves lay straight and smooth with
clearance from the recessed edge to prevent sticking. If a reed valve
curves away from the valve hole, remove the screw, flip the valve over
and reinstall.
6. Match the holes of the PTFE head gasket ("V") with the head seal
surface, install the head lid, and tighten the two center bolts with M4
lock washers first and then cross alternate tightening of the perimeter
bolts. Re-tighten the two center bolts after the other bolts are tight.
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