Gorman-Rupp Pumps U4B60S-B 1289525 and up - Manual (Page 38)

OM-05666 SUPER U SERIES
MAINTENANCE & REPAIR PAGE E - 14
and the impeller is .003 to .010 inch (0,07 to 0,25
mm).
Replace the suction back cover and wear plate O‐
rings (15 and 19) and lubricate them with a gener­
ous amount of No. 2 grease. Clean any scale or de­
bris from the contacting surfaces in the pump cas­
ing 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 (24) into the
tapped holes in the suction back cover plate until
they are just flush with the machined surface on
the back side of the cover plate.
Align the suction back cover plate over the studs
(23) and slide it into the pump casing. Use two
back cover nuts (22) on diagonally opposing studs
to press the suction back cover into the pump cas­
ing 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 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 suc­
tion back cover into the pump casing one full turn.
Pull the collars off the adjusting screws, index them
one detent counterclockwise, and reinstall the col­
lars 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 suction back cover plate. Secure the
locking collars to the suction back cover plate with
the hardware (25 and 26). 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 (25 and 26). 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 suction back
cover side of the pump, an additional 0.125 inch
(3,2 mm) of adjustment may be obtained by re­
moving the rotating assembly adjusting shims
(12).
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
suction back cover adjustment procedure de­
scribed above to obtain the proper face clearance.
PRESSURE RELIEF VALVE
MAINTENANCE
(Figure 1)
The suction back cover is equipped with a pres­
sure relief valve (35) to provide additional safety for
the pump and operator (refer to Liquid Tempera­
ture And Overheating in OPERATION).
It is recommended that the pressure relief valve as­
sembly be replaced at each overhaul, or any time
the pump overheats and activates the valve. Never
replace this valve with a substitute which has not
been specified or provided by the Gorman‐Rupp
Company.