Gorman-Rupp Pumps 04A20-B 818101 and up - Manual (Page 29)

OM-01206 0 SERIES
MAINTENANCE & REPAIR PAGE E - 9
Impeller Installation
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 3.
Use these measurements to calculate the required
impeller location (dimension E). Add or remove im­
peller adjusting shims (59) 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 3. Centering Impeller Within Volute Scroll
Install the correct thickness of impeller shims and
install the impeller key (9) in the shaft keyway. Align
the impeller keyway with the key and slide the im­
peller onto the shaft until fully seated.
Immobilize the impeller by inserting a bar between
the impeller vanes, being careful not to damage
the vanes. Secure the impeller with the hardware
(51, 52 and 53). Remove the bar from the impeller
vanes.
Pump Casing and Wear Ring Installation
If removed at disassembly, press the replacement
wear ring (57) into the pump casing until it seats
squarely against the shoulder bore.
The wear ring must seat squarely in the
casing bore or binding and/or excessive
wear will result.
Install the casing gasket (42) and secure the cas­
ing to the seal plate and pedestal with the nuts (41).
Reinstall any leveling shims under the casing
mounting feet, and secure the casing to the base
with the previously removed hardware.
NOTE
After the pump casing has been installed, check for
free shaft rotation. Correct any scraping binding
before further reassembly.
Final Pump Assembly
Be sure the pump and power source are securely
mounted to the base.
Install the suction and discharge lines and open all
valves. Make certain that all piping connections are
tight, properly supported and secure.
Be sure the pump, pedestal and power source
have been properly lubricated, see LUBRICA­
TION.
Fill the pump casing with clean liquid. Reinstall the
fill plug (58) and tighten it.
Refer to OPERATION, Section C, before putting
the pump back into service.