MIL-HDBK-1164
Table 12 (Continued)
Symptom
Possible Cause
Air leaks into pump through stuffing boxes.
Inlet of suction pipe insufficiently submerged.
Water-seal pipe plugged.
Seal cage improperly located in stuffing box,
preventing sealing fluid from entering space to
form the seal.
Pump requires excessive power.
Speed too high.
Wrong direction of rotation.
Total head of system higher than design head of
pump.
Total head of system lower than pump design
head.
Foreign matter in impeller existing conditions.
Misalignment.
Shaft bent.
Rotating part rubbing on stationary part.
Wearing rings worn.
Packing improperly installed.
Incorrect type of packing for operating conditions.
Gland too tight resulting in no flow of liquid to
lubricate packing.
Stuffing box leaks excessively.
Seal cage improperly located in stuffing box,
preventing sealing fluid entering space to form the
seal.
Misalignment.
Shaft bent.
Shaft or shaft sleeves worn or scored at the
packing.
Packing improperly installed.
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