If the pump still does not deliver flow, the cause may be one
or more of the following:
1.
Suction line air leaks. Vacuum gauge reading should help
determine if this is the problem.
2.
End of suction pipe not submerged deep enough in liquid.
3.
Suction lift is too great or the suction piping is too small.
4.
Liquid is vaporizing in the suction line before it
gets to the pump.
If after consideration of these points it still does not pump,
review again all points under
START UP
. Read through
Troubleshooting
in this manual and try again. If it still does
not pump, contact your Viking Pump
®
representative.
TROUBLESHOOTING
A Viking pump that is properly installed and maintained will
give long and satisfactory performance.
NOTE:
Before making any pump adjustment or opening the
pump liquid chamber in any manner, make sure that:
1.
Any pressure in the pumping chamber has been vented
through the suction or discharge lines or other openings
provided for this purpose.
2.
The driver has been “locked out” so that it cannot
inadvertently be started while work is being done
on the pump.
3.
The pump has been allowed to cool down to the point
where there is no chance of anyone being burned.
If trouble does develop, one of the first steps toward finding
the difficulty is to
install a vacuum gauge in the suction port
and a pressure gauge in the discharge port
. Readings on
these gauges often will give a clue as to where to start looking
for the trouble.
VACUUM GAUGE - SUCTION PORT
1. High reading would indicate:
a.
Suction line is blocked by a stuck foot valve,
stuck gate valve, or plugged strainer.
b.
Liquid is too viscous to flow through the piping.
c.
Lift is too high.
d.
Line is too small.
2. Low reading would indicate:
a.
Air leak in suction line.
b.
End of pipe is not in liquid.
c.
Pump is worn.
d.
Pump is dry - should be primed.
3. Fluttering, jumping, or erratic reading:
a.
Liquid is vaporizing.
b.
Liquid is coming to pump in slugs, possibly an air leak,
insufficient liquid above the end of the suction pipe.
c.
Vibrating from cavitation, misalignment,
or damaged parts.
PRESSURE GAUGE - DISCHARGE PORT
1. High reading would indicate:
a.
High viscosity, small diameter discharge line or long
discharge line.
b.
Gate valve is partially closed.
c.
Filter is plugged.
d.
Vertical head did not consider a high specific
gravity liquid.
e.
Line is partially plugged from build up on inside of pipe.
f.
Liquid in the pipe is not up to temperature.
g.
Liquid in the pipe has undergone a chemical reaction
and has solidified.
h.
Relief valve is set too high.
2. Low reading would indicate:
a.
Relief valve is set too low.
b.
Relief valve poppet is not seating properly.
c.
Bypass around the pump is partially open.
d.
Too much extra clearance.
e.
Pump is worn.
3. Fluttering, jumping, or erratic reading:
a.
Cavitation.
b.
Liquid is coming to the pump in slugs.
c.
Air leak is in the suction line.
d.
Vibrating from misalignment or mechanical problems.
Some of the following may also help pinpoint the
problem:
A. Pump does not pump.
1.
Pump has lost its prime due to air leak, low level in
tank, foot valve stuck.
2.
Suction lift is too high.
3.
Rotating in wrong direction.
4.
Motor does not come up to speed.
5.
Suction and discharge valves not open.
6.
Strainer is clogged.
7.
Bypass valve open, relief valve set too low, relief valve
poppet stuck open.
8.
Pump is worn out.
9.
Any changes in the liquid system or operation that
would help explain the trouble, e.g. new source of
supply, added more lines, inexperienced operators, etc.
10.
Too much end clearance.
11.
Head position is incorrect. See
Figure A3
.
12.
Temperature changes either in the liquid or environment.
13. Mag Drive pumps ONLY:
The magnetic coupling
is decoupling. Changes in application (temperature,
pressure, viscosity, etc.) may require torque beyond
coupling capabilities.
B. Pump starts, then loses its prime.
1.
Supply tank is empty.
2.
Liquid is vaporizing in the suction line.
3.
Air leaks or air pockets in the suction line; leaking air
through packing or mechanical seal.
4.
Pump is worn out.
TSM 1741 | Issue B | Page 16 of 20
© 2019 Viking Pump, Inc. • Cedar Falls, IA
© Viking Pump, Inc.
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© Viking Pump, Inc.
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