Gorman-Rupp Pumps SF4A 1488019 and up - Manual (Page 44)

OM-06432 SF SERIES
PAGE E - 19 MAINTENANCE AND REPAIR
See Figure E-4 and connect the vacuum pump or
compressor/venturi system directly to the pump at
the hole for the seal cavity drain plug (7, Figure
E-2).
Draw the seal cavity vacuum down to not more
than 10 In. Hg. and hold for 10 minutes. If no
change in vacuum reading is detected, proceed
with LUBRICATION.
Do not draw the seal cavity vacuum below
10 In. Hg. Lower vacuum can cause sepa­
ration of the seal faces and/or unseating of
the upper seal stationary seat, resulting in
seal leakage.
Seal and Motor Cavity Testing
Connect the vacuum pump or compressor/venturi
system to the pump as shown in Figure E-4.
If the compressor/venturi cannot draw the higher
vacuum level shown in Table E-1, draw the motor
cavity vacuum down as far as the system will allow,
then draw the seal cavity down so the differential
between the two cavities is the same as the differ­
ential between the vacuum readings shown in the
table.
To vacuum test the motor cavity, the terminal hous­
ing assembly must be replaced with a test plate.
Make the test plate as shown in Figure E-5 below,
install the terminal housing O‐ring under the test
plate, then proceed with vacuum testing.
.438” (11,1 mm) dia. drill
thru. Tap .250‐18 NPT.
12 mm dia. drill thru (4) holes
equally spaced on a 4.72 (120 mm)
diameter bolt circle.
Install terminal
housing O‐ring
for test.
3.749 - 3.750 in
(95,22 - 95,25 mm)
1.5 in.
(38,1 mm)
.75 in.
(19,1 mm)
5.5 in.
(139,7 mm)
Make from commercially available steel plate.
45 _ x 1/8” (3,1 mm)
Chamfer
Figure E-5. Motor Vacuum Test Plate
Install full‐closing ball‐type shutoff valves with
quick‐disconnect fittings in the pipe plug holes in
both the motor and seal cavities. Test the motor
cavity for its full duration first, then use the shutoff
valve to maintain the motor cavity vacuum while
testing the seal cavity. The motor cavity vacuum
must be higher than the vacuum in the seal cavity
to prevent separation of the seal faces or unseating
the stationary seal seat between the seal and mo­
tor cavities. Figure E-4 shows a simple schematic for setting
up either a vacuum pump or a venturi/compressor
test system.
Table E-1 shows the vacuum to be drawn on each
cavity, and the duration to maintain each vacuum
reading. Any change in vacuum reading during
the test indicates a leak which must be identified
and corrected before putting the pump back into
service.
Table E-1. Vacuum Test Data
Seal Cavity
Vacuum
(In. Hg.)
Motor Cavity
Vacuum
(In. Hg.)
Duration
(Minutes)
Duration
(Minutes)
20 3 30 1