Multiquip Trash Pump QP3TY - Manual (Page 20)

PAGE 20 — QP3TY TRASH PUMP — OPERATION AND PARTS MANUAL — REV. #2 (11/15/10)
QP3TY — 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 13, 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 13) 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
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.
Adjusting Impeller Clearance
1. If it is necessary to replace impeller or volute, be sure
clearance between impeller and volute is adjusted correctly.
2. The impeller should be as close to the volute as possible
without rubbing against it. Clearance is adjusted by adding
or removing
shims from behind the impeller.
3. Check clearance between impeller and insert by slowly
pulling starter rope to turn impeller. Remove spark plug to
make it easier to turn impeller.
25 in. Hg. (inches of mercury)
translates into 25 feet of lift at
sea
level .
NOTE
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.
6. 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.
It is important not to remove too
many shims or the clearance
between the impeller and volute will
become
too wide and pump
performance will be reduced.
Remember as the impeller wear
down, additional shims may be required to maintain the
clearance between the impeller and insert.
4. Check the impeller every six months for wear, and for
clearance between the impeller face and the volute. Also
check the shaft seal for wear, as well as the shaft sleeve.
Pump Cleaning
After pumping water containing large amounts of dirt and debris,
perform the following:
1. Remove the drain plug from the pump housing (Figure 2)
and drain any water left in the pump.
2. Loosen the two locking hand knobs (turn counterclockwise)
and remove clean-out cover .
3. Clean and remove dirt, debris from pump casing. Inspect
impeller and volute for wear. Replace any damaged or worn
parts.
The impeller may develop sharp edges . Use extreme care
when cleaning around the impeller to prevent being cut.
NOTE
CAUTI CAUTI CAUTI CAUTI CAUTION
CAUTI CAUTI CAUTI CAUTI CAUTION