TM 5-3895-374-24-2
Section V - Pump Trouble Shooting
PUMP TROUBLE
POSSIBLE CAUSE
No liquid delivered, not enough liquid delivered, or not enough
1, 2, 3, 4, 5, 6, 7, 8, 11, 12, 13,14, 17, 18, 19, 21, 22, 23
pressure
Pump works a while and then quits
1, 2, 3, 4, 5, 11, 13, 14, 17, 19, 23, also refer to Section III
Para A
Pun:p is noisy or vibrates
1, 2, 3, 4, 10, 16, 19, 20, 29, also refer to Section II, Para. C
Pump uses too much power
1, 2, 3, 8, 9, 12, 18, 19, 24, 25, 26, 35
Pump leaks excessively at shaft sealing area, or shaft sealing
1, 2, 14, 15, 20, 26, 27, also refer to Section IV, Para. B.
area over heating
High bearing temperature
1, 2, 3, 9, 20, 28, 29, 30, 31, 32, 33, 34, also refer to Section IV,
Para. A
Possible Causes of Trouble
1.
Mechanical defects, which may include a bent
shaft, binding impeller, or other parts. The
defect should be corrected as soon as possible
to prevent serious damage to the pump.
2.
Improper system design should be redesigned
and corrected as necessary.
3.
Foreign body in pump make provisions to keep
such particles out or use a pump designed to
handle the required size of solid. Disassemble
the pump or piping and remove any obstruction
present.
4.
Insufficient NPSH or excessive suction lift,
cavitation and mechanical damage can result.
5.
Pump not primed or improperly vented check
that casing and suction pipe are completely filled
with liquid.
6.
Speed too low check motor nameplate rating.
7.
System resistance too high check system head.
8.
Pumping
over
capacity,
control
flow
with
discharge valve. (Never with the suction valve).
9.
Driver temperature high check driver nameplate
for design temperature rise. Check horsepower
requirements.
10.
Foundations not rigid.
11.
Impeller or piping obstructed.
12.
Wrong direction of rotation. Refer to Sect. III
Para. A2.
13.
Air pocket or leak in suction line check suction
piping for air pockets and/or leaks.
14.
Radial seal rings worn, allowing leakage of air
into pump casing check seal rings and replace
as required. Check for proper lubrication.
15.
Shaft worn or scored at the seal ring.
16.
Noise caused by other equipment.
17.
Entrained air or gas in liquid system problem.
18.
Impeller clearance too great restore proper
clearance.
19.
Impeller damaged inspect and replace as
required.
20.
Coupling or pump and driver misaligned check
alignment and realign if required.
21.
Impeller diameter too small consult factory for
proper impeller diameter.
22.
Improper pressure gauge location check correct
position.
23.
gaskets damaged check gaskets and replace as
required.
24.
Speed too high check motor nameplate rating
25.
Liquid heavier than anticipated. Check specific
gravity and viscosity at start-up and operating.
26.
Seal rings not properly installed.
27.
Incorrect seal rings consult factory.
28.
Pump capacity too low consult factory for
minimum continuous flow.
29.
Improper
bearing
lubrication
or
defective
bearings inspect and replace as required.
30.
Excessive grease in bearing housing.
31.
Lack of lubrication.
32.
Improper installation of bearing.
33.
Dirt getting into bearing.
34.
Bearing temperature always high. This may be
the bearing operating temperature. Grease
lubricated bearings are operated at 2000F.
(100,C.) with the proper lubricant.
NOTE: Maximum temperature most people can
hold their hands against is 120-130°F. (50-
55°C.).
35. Impeller diameter too large consult factory for
proper impeller diameter.
(page 3 - 1145
