Gorman-Rupp Pumps PA4B60-4045H 1417817 thru 1497875 - Manual (Page 43)

OM−06228 PA SERIES
MAINTENANCE & REPAIR PAGE E − 21
suction head; otherwise binding and/or ex-
cessive wear will result.
Inspect the impeller and replace it if cracked or
badly worn.
For maximum pump efficiency, the impeller should
be centered within the volute scroll.
To verify the impeller positioning, measure the
pump casing and impeller as shown in Figure 10.
Use these measurements to calculate the required
impeller location (dimension E). Add or remove im-
peller adjusting shims (48) until dimension E is ob-
tained.
D
B
2
A B
2
C D
E
Step 2 Step 1 Step 3
A+
B
2
C+
D
2
E = −
Figure 10. Centering Impeller Within Volute Scroll
Install the calculated thickness of impeller shims
(48). Install the impeller key (40) and slide the im-
peller completely onto the shaft.
Secure the shaft from rotating by reaching through
the discharge port and tightly wedging a soft-metal
bar between the vanes of the impeller. Secure the
impeller with the impeller washer and nut (37 and
38).
NOTE
After the impeller has been properly positioned,
check for free rotation. Correct any scraping bind-
ing before further reassembly.
Suction Head Installation
(Figure 4)
If removed at disassembly, press the replacement
wear ring (36) into the suction head (42) until it
seats squarely against the bore shoulder.
The wear ring must seat squarely in the
suction head; otherwise binding and/or ex-
cessive wear will result.
Install the suction head gasket (44) and secure the
suction head to the pump casing with the nuts (34).
Make sure the jacking screws (39) do not interfere
with the suction head seating.
Discharge Check Valve Assembly And
Installation
(Figure 3)
The flapper and cover O-ring are the only service-
able parts of the check valve. If the flapper requires
replacement, remove the hardware securing the
cover and O-ring. Separate the valve cover and re-
place the flapper.
Install the valve cover O-ring and secure the cover
with the previously removed hardware.
Support the discharge check valve assembly (7)
using a sling and a suitable lifting device. Use the