18
WILDEN PUMP & ENGINEERING, LLC
WIL-10220-E-02
The air valve assembly consists of both the air valve body and
piston and the center block. The unique design of the air valve
relies only on differential pressure to effect the diaphragm shift.
It is reliable and simple to maintain. The bushing in the center
block, along with the diaphragm shaft, provides the “trigger”
to tell the air valve to shift. The following procedure will ensure
that the air valve on your Wilden pump will provide long
trouble-free service.
If the piston does not move freely in the air valve, the entire
air valve should be immersed in a cleaning solution. [
NOTE:
Do not force the piston by inserting a metal object.] This
soaking should remove any accumulation of sludge and
grit which is preventing the air valve piston from moving
freely. Also, remove and clean the air valve screen (P/N 04-
2500-03). If the air valve piston does not move freely after
the above cleaning, the air valve should be disassembled
as follows: Remove the snap ring from the top end of the
air valve cylinder and apply an air jet to the 3/16-inch hole
on the opposite end of the air valve face (see
Figure C).
CAUTION:
The air valve end cap may come out with consid-
erable force. Inspect the piston and cylinder bore for nicks
and scoring.
AIR VALVE DISASSEMBLY:
The air valve (P/N 04-2000-07) can be disconnected from
the pump by removing the four socket head cap screws
which attach it to the center block. The piston should move
freely and the ports in the piston should line up with the
ports on the face of the air valve body (see
Figure D).
The
piston should also appear to be dull, dark gray in color. If the
piston appears to be a shiny aluminum color, the air valve
is probably worn beyond working tolerances and should be
replaced.
Figure A
Figure B
Figure C
Figure D
CENTER
BLOCK
AIR FILTER
SCREEN
AIR VALVE
PISTON
CENTER BLOCK
BUSHING
AIR INLET
END CAP
AIR VALVE ASSEMBLY
AIR VALVE
BODY
SECTION 8B
AIR VALVE / CENTER BLOCK
DISASSEMBLY
