Ebbco GRS-0250-B-CC - Page 12

Page 13
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permission of Ebbco Inc. or its subsidiaries.
Section 5: Troubleshooting Guide
5.2 Sy
stem Pump
For troubleshooting pumps, read symptom describing problem, consult keyed causes and correct those
that apply. Caution: be sure unit’s power is disconnected before attempting any work on pump or motor.
SYMPTOM KEY NUMBERS FOR CAUSES
A
Pump does not deliver liqui
d 1,2,3,4,6,10,1
2,14,15,20,21
B
Pump delivers too little flow 2,3,4,5,6,7,10,11,12,13,15,18,20,21,27,28
C
Delivery pressure too
low 5,12,13,14,1
5,
18,20,27,28
D
Pump loses prime after starting 2,3,5,6,7,10
E
Pump needs too much power 13,15,16,17,18,21,22,24,25,27
F
Seal leaks 22,24,29,30
G
Pump vibrates or is noisy 2,3,4,10,19,21,22,23,24,25,26,28,29,30,31,
32,33,34
H
Motor bearings have short life 22,24,25,26,29,30
I
Pump overheats and/or seizes 1,4,19,20,22,25,26,29,30
CAUSES
1
Pump not primed
18
Viscosity of liquid different than design
2
Pump or suction pipe not completely full of
liquid
19
Pump operating at very low capacity
3
Suction lift too high
20
Parallel operation of pumps unsuited for such
operation
4
Pump cavitating, increase suction pressure
21
Foreign matter in impeller
5
Excessive amount of air/gas in liquid
22
Misalignment of pump or piping
6
Air pockets in suction pipe
23
Foundations not rigid
7
Air leakage in suction pipe
24
Shaft bent
25
Rotating part rubbing on stationary part
26
Bearings worn
10
Suction pipe not sufficiently submerged
27
Wear ring worn
11
Impeller, suction or trap partially or
completely plugged
28
Impeller damaged
12
Speed too low
29
Shaft running off center due to worn bearings
or misalignment
13
Voltage wrong or too low
30
Impeller out of balance resulting in vibration
14
Wrong direction of rotation
31
Excessive grease in bearing causing high
bearing temperature
15
System head too high for pump design
32
Lack of lubrication
16
System head too low for system design
33
Dirt in bearings
17
Specific gravity of liquid different than
design
34
Rust in bearings due to water getting into
motor