Gorman-Rupp Pumps PAH4A60C-B 1512735 and up - Manual (Page 39)

PAH SERIES OM-06443
MAINTENANCE & REPAIR PAGE E - 18
Apply `Loctite Retaining Compound No. 242' or
equivalent to the threads of the impeller capscrew
(2). Install the roll pin (4) in the hole in the impeller.
Position the impeller washer over the end of the im­
peller shaft so the hole in the washer aligns with the
roll pin. Block impeller rotation as described in Im­
peller Removal and torque the impeller capscrew
to 180 ft. lbs. (24,9 m. kg.).
Pump Casing Installation
(Figure 2)
Lubricate the O‐ring (3) with light grease and install
it in the groove in the O.D. of the seal plate. Install a
lifting eye in the uppermost hole in the pump cas­
ing (1) for the pipe plug (5). Be sure to screw the
lifting eye tightly into the hole as far as it will go. At­
tach a suitable lifting device to the lifting eye and
use the lifting device to position the pump casing
over the rotating assembly. Install the hardware (7
and 8) on the studs (6) and use the hardware to ful­
ly seat the pump casing against the seal plate (9,
Figure 3).
Suction Head and Wear Ring Installation and
Adjustment
(Figure 2)
If the wear ring (2) was removed, position the re­
placement wear ring in the suction head (16) and
use an arbor (or hydraulic) press to press it into the
suction head until fully seated.
Install the O‐ring (3) in the groove in the O.D. of the
suction head and lubricate it with light grease.
Position the suction head over the studs (10).
The clearance between the wear ring and the im­
peller is adjusted using the four back cover nuts
(13) and locking collars (12). There are 18 detents
on the I.D. of each locking collar. Indexing the col­
lars one detent on the adjusting screws represents
approximately .005 inch (0,13 mm) of wear plate
clearance. The recommended clearance between
the wear ring and the impeller is .008 to .015 inch
(0,2 to 0,4 mm).
Screw the four adjusting screws (11) into the
tapped holes in the back cover plate until they are
just flush with the machined surface on the back
side of the cover plate.
Use two back cover nuts on diagonally opposing
studs (10) to press the suction head into the pump
casing until the wear ring just touches the impeller
when the shaft is turned. Tighten the back cover
nuts evenly to avoid binding.
With the wear ring just touching the impeller, turn
the two free adjusting screws until they engage the
pump casing. Position the locking collars over the
adjusting screws so the holes in the collars for the
locking screws align approximately with the holes
in the suction head.
Loosen the back cover nuts used to press the
suction head into the pump casing one full turn.
Pull the collars off the adjusting screws, index them
three detents counterclockwise, and reinstall the
collars on the adjusting screws. Use the collars to
turn the adjusting screws clockwise until the holes
in the locking collars realign with the tapped screw
holes in the back cover plate. Secure the locking
collars to the back cover plate with the hardware
(14 and 15). Install the two remaining hand knobs
snugly against the adjusting screws.
Remove the first two back cover nuts from their
studs. Turn the adjusting screws clockwise until
they engage the pump casing. Install the locking
collars and hardware (14 and 15). Reinstall the
back cover nuts.
Be sure the wear ring does not scrape against the
impeller when the shaft is turned.
After the face clearance has been set, tighten the
hardware securing the rotating assembly to the
pump casing.
Discharge Check Valve Reassembly And
Installation
(Figure 1)
If the discharge check valve (23) was disas­
sembled to replace the flapper or cover O‐ring,
position the flapper in the valve body and check to
ensure free movement.
Install the valve cover O‐ring and secure the cover
to the body with the previously removed hardware.
Apply a small amount of light grease to the dis­
charge flange gasket to hold it in place and posi­
tion it against the pump casing flange. Support the
discharge check valve assembly using a sling and
a suitable lifting device. Using the previously re­