Gorman-Rupp Pumps 16A20-B 818301 and up - Manual (Page 33)

10 SERIES OM‐00710
MAINTENANCE & REPAIR PAGE E - 10
Impeller Installation and Adjustment
Inspect the impeller and replace it if cracked or
badly worn. Install the same thickness of impeller
shims (22) as previously removed. Apply `Never‐
Seez' or equivalent to the shaft threads and screw
the impeller onto the shaft until tight.
A clearance of .010 to .040 inch (0,25 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 shims until
this clearance is reached.
NOTE
Be sure the seal plate is tight against the pedestal
while measuring this clearance.
Install the impeller washer and capscrew (60 and
61). Immobilize the impeller shaft as indicated in
Impeller Removal and secure the impeller to the
shaft by torquing the impeller screw to 90 ft. lbs.
(12,4 m. kg.).
Pump Casing Installation
Remove the hardware temporarily securing the
seal plate to the pedestal. Install the same thick­
ness of pump casing gaskets (59) as previously re­
moved and secure the pump casing to the seal
plate and pedestal with the nuts (57). Do not fully
tighten the nuts at this time.
NOTE
The back cover assembly must be in place to adjust
the impeller face clearance.
A clearance of .008 to .015 inch (0,20 to 0,38 mm)
between the impeller and the wear plate (73) is also
recommended for maximum pump efficiency. Set
this clearance by adding or removing gaskets in
the pump casing gasket set (59) until the impeller
scrapes against the wear plate when the shaft is
turned by hand. After the impeller scrapes, add ap­
proximately .008 inch (0,20 mm) of gaskets.
After the face clearance has been set, tighten the
nuts (57) securing the pump casing to the pedes­
tal.
Back Cover Installation
If the wear plate (73) was removed for replace­
ment, secure it to the cover plate (66) using the at­
taching hardware (63 and 64) at this time. The wear
plate must be concentric to prevent binding when
the back cover is installed.
Clean any scales or debris from the contacting sur­
faces on the pump casing that might prevent a
good seal with the back cover. Replace the back
cover gasket (65) and slide the back cover assem­
bly (66) into the pump casing. Be sure the wear
plate does not bind against the impeller.
NOTE
To ease future disassembly, apply a film of grease
or `Never‐Seez' on the back cover shoulder, or any
surface that contacts the pump casing. This action
will reduce rust and scale build‐up.
Secure the back cover assembly by installing the
clamp bar (72) and tightening the clamp bar screw
(71). Do not over‐tighten the clamp bar screw; it
should be just tight enough to seal the back cover
shoulder.
Suction Check Valve Installation
(Figure E-1)
NOTE
When replacing the gaskets (74 and 76) apply `Per­
matex Aviation No. 3 Form‐A‐Gasket' or equivalent
compound to the mating surfaces.
Inspect the check valve components and replace
as required. Subassemble the check valve weights
(84 and 86) and check valve gasket (85) using the
attaching hardware (82 and 83).
Install the check valve assembly (81) in the check
valve seat (75) with the large weight towards the in­
side of the casing. Install the gasket (74) and se­
cure the check valve seat to the pump casing with
the screws (80). Install the gasket (76) and suction
flange (87) and secure with the hardware (77 and
78). Check the operation of the check valve to en­
sure proper seating and free movement.
(Figure 3)
Inspect the check valve components, and replace
the parts as required. Subassemble the check