PA SERIES PUMPS
MR−05740
MAINTENANCE & REPAIR
PAGE C − 20
collars to the back cover plate with the hardware
(35 and 36). Install the two remaining hand knobs
snugly against the adjusting screws.
Remove the first two hand knobs from their studs.
Turn the adjusting screws clockwise until they en-
gage the pump casing. Install the locking collars
and hardware (35 and 36). Reinstall the hand
knobs.
Be sure the wear plate does not scrape against the
impeller.
Over time it may be necessary to repeat the adjust-
ment process to compensate for normal wear be-
tween the impeller and wear plate. When all of the
adjustment has been used on the back cover side
of the pump, an additional 0.125 inch (3,2 mm) of
adjustment may be obtained by removing the ro-
tating assembly adjusting shims (11).
Allow an installed pump to completely cool before
draining liquid from the pump casing. Disengage
the hardware (9 and 10), remove the rotating as-
sembly adjusting shims, then reinstall the hard-
ware securing the rotating assembly to the pump
casing. Reach through the suction opening and
measure the clearance between the wear ring and
impeller. Perform the back cover adjustment pro-
cedure described above to obtain the proper face
clearance.
Priming Chamber Assembly And Installation
(Figure C−3)
Clean and inspect the components of the priming
valve (1). Inspect the linkage and ensure the orifice
button (2) squarely engages the valve seat. Re-
place the orifice button if required (see
Priming
Chamber Removal and Disassembly
for orifice
button removal).
If the orifice button was removed, screw the new
orifice button into the linkage bar until fully seated.
Align the hole in the linkage bar with the holes in the
bracket and reinstall the pivot pin. Secure the pivot
pin with the previously removed e-clip".
Adjust the orifice button seating as necessary by
screwing the orifice button into or out of the linkage
bar. Proper adjustment is achieved when the ori-
fice button fully seats against the orifice before the
linkage bar on the float bottoms against the
threads on the orifice button. When adjustment is
complete, install and tighten the lock washer and
hex nut securing the orifice button.
Install the strainer (5) and priming valve gasket (7).
Lower the float into the priming chamber (6) and
secure the priming valve with the previously re-
moved hardware (3 and 4).
(Figure C−2)
Install the baffle (9) and gasket (8) and use a sling
and suitable lifting device to position the priming
chamber assembly on the hopper spool (6, Figure
C−3). Secure the priming chamber assembly with
the hardware (6 and 7).
Reconnect the suction piping to the hopper spool
and the air discharge tubing to the priming cham-
ber assembly.
Discharge Check Valve Assembly And
Installation
(Figure C−1)
The flapper and cover O-ring are the only service-
able parts of the check valve. If the flapper requires
replacement, remove the flapper as indicated in
Discharge Check Valve Removal and Disas-
sembly
.
Seat the new flapper in the check valve body and
ensure that it moves freely. Install the valve cover
O-ring and secure the cover with the previously re-
moved hardware. After installing the cover, check
for free movement of the flapper.
Secure the discharge check valve assembly to the
pump casing with the previously removed hard-
ware.
Wear Ring Adjustment
(Figure C−4)
Pump performance is adversely affected by in-
creased clearance between the wear ring (5) and
the impeller. When it becomes necessary to adjust
the clearance, loosen the hand knobs (19) and pry
the back cover approximately 1/8 inch (3,2 mm)
out of the pump casing.
