Xylem A-C Fire Pump – Vertical Turbine Fire Pump AC8499 - Manual (Page 19)

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7. Pump is too noisy A. Cavitation (insufficient NPSH Increase liquid level in sump.
available)
B. Bent shaft Straighten as required.
C. Rotating parts binding, loose Replace as required.
or broken
D. Bearings are worn out Replace bearings.
8. Excessive vibrations A. Coupling misalignment, bent Determine cause utilizing shaft
impeller unbalance, worn vibration frequency analyzer
bearings, cavitation, piping strain and/or pump disassemble.
and/or resonance Complex problem may require
factory service assistance.
B. Motor or gear driveshaft end See Installation of Hollow Shaft
play maladjustment Driver (VHS).
9. Pump leaks excessively A. Defective packing Replace worn packing. Replace
at stuffing box packing damaged by lack of lubrication.
B. Wrong type of packing Replace packing not properly
installed or run-in. Replace
improper packing with correct
grade or liquid being pumped.
10. Stuffing box is A. Packing is too tight Release gland pressure. See step 6 F
overheating
B. Packing is not lubricated Release gland pressure and replace all
packing if burnt or damaged. Re-grease
packing as required.
C. Wrong grade of packing Consult factory.
D. Stuffing box improperly Repack stuffing box.
packed
11. Packing wears too fast A. Shaft or shaft sleeve worn or Pull pump and remachine, or
replace shaft and/or sleeve.
B. Insufficient or no Repack and make sure packing is
lubrication loose enough to allow some leakage.
C. Improperly packed Repack properly, make sure all
old packing is removed and
stuffing box is clean.
D. Wrong grade of packing Consult factory.
TROUBLE PROBABLE CAUSE REMEDY
5. Pump works for a while A. Excessive horsepower Use larger driver.
and quits required Consult factory.
B. Pumping higher viscosity or specific Test liquid for viscosity and
gravity liquid than designed for specific gravity.
C. Mechanical failure of Check bearings and impellers
critical parts for damage. Any irregularities
in these parts will cause a
drag on the shaft.
D. Speed may be too high Check frequency on motor.
E. Misalignment Re-align pump and driver.
6. Pump takes too much A. Damaged impeller Inspect, replace if damaged.
power B. Foreign object lodged between Remove object as required.
impeller and bowl
C. Specific gravity higher than Test liquid for viscosity and
pump designed for specific gravity.
D. Viscosity too high, partial Check for both. They can cause
freezing of pumpage drag on impeller.
E. Defective bearing Replace bearing, check shaft or
shaft sleeve for scoring.
F. Packing is too tight Release gland pressure.
Retighten. Refer to Packing
Adjustment and Replacement
(page 24). Keep leakage
flowing. If no leakage, check
packing, sleeve or shaft.