Gorman-Rupp Pumps PAH8A60C-B 1537579 and up - Manual (Page 40)

PAH SERIES OM-06455
MAINTENANCE & REPAIR PAGE E - 18
Slide the rotating subassembly (consisting of the
rotating element, retainer and bellows) onto the
sleeve until the rotating element is just flush with
the chamfered end of the sleeve. Slide the shaft
sleeve and rotating subassembly onto the shaft
until the seal faces contact and the shaft sleeve
seats against the shoulder on the impeller shaft.
Install the seal spring and spring centering washer.
Lubricate the seal assembly as indicated in
LUBRICATION, after the impeller has been in­
stalled.
Impeller Installation and Adjustment
(Figure 3)
Inspect the impeller (1) and replace it if cracked or
badly worn.
Install the same thickness of adjusting shims (5) as
previously installed. Install the impeller key (26) in
the shaft keyway. Align the keyway in the impeller
with the shaft key and press the impeller onto the
shaft until fully seated.
A clearance of .025 to .040 inch (0,64 to 1,02 mm)
between the impeller and the seal plate is neces­
sary for maximum pump efficiency. Measure this
clearance and add or remove impeller adjusting
shims as required.
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 (3A) with light grease and in­
stall it in the groove in the O.D. of the seal plate.
Install a lifting eye in the uppermost hole in the
pump casing (1) for the pipe plug (5). Be sure to
screw the lifting eye tightly into the hole as far as it
will go. Attach a suitable lifting device to the lifting
eye and use the lifting device to position the pump
casing over the rotating assembly. Install the hard­
ware (8 and 9) on the studs (7) and use the hard­
ware to fully 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 (10) was removed, position the re­
placement wear ring in the suction head (2) 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 (11).
The clearance between the wear ring and the im­
peller is adjusted using the four back cover nuts
(15) and locking collars (13). 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 (12) 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 (11) 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 16). Install the two remaining hand knobs
snugly against the adjusting screws.