Gorman-Rupp Pumps U3B60S-B 1289509 and up - Manual (Page 37)

OM-05663 SUPER U SERIES
MAINTENANCE & REPAIR PAGE E - 14
Back Cover Installation And Adjustment
(Figure 1 and 5)
If the wear plate (9) was removed for replacement,
carefully center it on the back cover and secure it
with the hardware (11 and 12). The wear plate
must be concentric to prevent binding when the
back cover is installed.
Clearance between the impeller and wear plate is
adjusted using four adjusting screws and locking
collars. There are 18 detents on the I.D. of each
locking collar. Indexing the collars one detent on
the adjusting screws represents approximately
.005 inch (0,13 mm) of wear plate clearance. The
recommended clearance between the wear plate
and the impeller is .003 to .010 inch (0,07 to 0,25
mm).
Replace the back cover and wear plate O‐rings (10
and 13), and lubricate them with a generous
amount of No. 2 grease. Clean any scale or debris
from the contacting surfaces in the pump casing
that might interfere or prevent a good seal with the
back cover.
USE TWO
OPPOSING
BACK COVER NUTS
TO PRESS
BACK COVER
INTO PUMP
CASING USE TWO REMAINING
ADJUSTING SCREWS AND
LOCKING COLLARS TO
SET FACE CLEARANCE
INDEX COLLARS 3
DETENTS COUNTER‐
CLOCKWISE, THEN
TURN CLOCKWISE
UNTIL SCREW
HOLES ALIGN
Figure 8. Installing and Adjusting Back Cover
Screw the four adjusting screws (26) 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.
Align the back cover plate over the studs (28) and
slide it into the pump casing. Use two back cover
nuts (27) on diagonally opposing studs to press
the back cover into the pump casing until the wear
plate just touches the impeller when the shaft is
turned by hand. Tighten the back cover nuts
evenly to avoid binding.
With the wear plate just touching the impeller, turn
the two free adjusting screws until they engage the
pump casing. Position the locking collars (25) over
the adjusting screws so the holes in the collars for
the locking screws align approximately with the
holes in the cover plate.
Loosen the back cover nuts used to press the back
cover 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
(23 and 24). Install the two remaining back cover
nuts 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 (23 and 24). Reinstall the
back cover nuts.
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 (6).
Allow an installed pump to completely cool before
draining liquid from the pump casing. Remove the
back cover. Remove the rotating assembly adjust­
ing shims, then reinstall the hardware securing the
rotating assembly to the pump casing. Perform the
back cover adjustment procedure described
above to obtain the proper face clearance.