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PAGE 20 — QP-402H CENTRIFUGAL PUMP — OPERATION AND PARTS MANUAL — REV. #1 (04/02/08)
QP-402H — MAINTENANCE (PUMP)
To perform the pump vacuum test do the following:
1. Remove the pump fill cap (Figure 2), and fill the pump
with water.
2. Start the engine as outlined in the initial start-up section,
and wait for the pump to begin pumping.
3. As shown in Figure 18 (next page), place a water hose
inside the discharge opening of the pump, and turn on
the water. This flow of water into the discharge opening
will
prevent
the pump from running dry.
4. Place the
Pump Vacuum Tester
(P/N 7000030)
over
the pump suction (inlet) opening (Figure 17) with the
vacuum gauge facing upwards. It may be necessary to
apply a small amount of water around the rubber seal of
the vacuum tester to make a good suction fit.
5. Check and make sure that there are no air leaks between
the vacuum tester and the inlet port on the pump. If air
leaks are present reset vacuum tester.
6. Run the pump for a few minutes while monitoring the
vacuum gauge. If the gauge indicates a reading between
-25 and -20 in. Hg. (inches of mercury) then it can be
assumed that the pump is working correctly.
Pump Vacuum Test
25 in. Hg (inches of mercury)
translates into 25 feet of lift at
sea
level
.
7. If the vacuum tester gauge indicates a reading
below
-20 in. Hg, it can then be assumed that the pump
is not functioning correctly, and corrective action needs
to be taken.
8. To test the
flapper valve
, shut down the engine. The
vacuum tester should remain attached to the pump
suction inlet port by vacuum. This indicates the pump's
flapper valve is seating properly to hold water in the
suction hose when the engine is stopped. This prevents
backflow and allows for faster priming when the engine
is restarted.
NOTE
CAUTION - Pump Priming
DO NOT attempt to start the engine unless the pump has
previously been
primed
with water. Severe pump damage
will occur if pump has not been primed.