Taco VT Series

9
H: TROUBLE SHOOTING
H1: TROUBLE SHOOTING
INSUFFICIENT PRESSURE
1. Speed too slow (check voltage)
2. Impeller trimmed incorrectly
3. Impeller loose
4. Impeller plugged
5. Wear rings worn
6. Entrained air in pump
7. Leaking joints or bowl casings
8. Wrong rotation
9. Incorrect impeller adjustment
NO LIQUID DELIVERED
1. Pump suction broken (water level below inlet)
2. Suction valve closed
3. Impeller plugged
4. Strainer clogged
5. Wrong rotation
6. Shaft broken or unscrewed
7. Impeller loose
8. Barrel or discharge not vented
9. Driver inoperative
VIBRATION
1. Motor imbalance (electrical)
2. Motor bearing is not properly seated or is worn
3. Motor drive coupling out of balance or alignment
4. Misalignment of pump, casing, discharge head,
column, and/or bowls
5. Discharge head misaligned by improper mounting
or pipe strain
6. Bent shafting
7. Worn pump bearings
8. Clogged impeller or foreign material in pump
9. Improper impeller adjustment
10. Vortex problems in sump
11. Resonance (system frequency at or near pump speed)
12. Cavitation
13. Impeller out of balance
INSUFFICIENT CAPACITY
1. Speed too slow
2. Impeller trimmed incorrectly
3. Impeller loose
4. Impeller or bowl partially plugged
5. Leaking joints
6. Strainer or suction pipe clogged
7. Suction valve throttled
8. Low water level
9. Wrong rotation
10. Insufficient submergence
11. Insufficient N.P.S.H.
12. Incorrect impeller adjustment
13. Worn pump
14. Pressure higher than design
USING TOO MUCH POWER
1. Speed too high
2. Improper impeller adjustment
3. Improper impeller trim
4. Pump out of alignment
5. Coupling out of alignment
6. Pumping foreign material
7. Lubrication oil too heavy
8. Bent shaft
9. Tight bearing or packing
10. Specific gravity or viscosity of fluid higher than design
11. Worn pump
12. Damaged pump
13. Partial freezing of pump liquid
ABNORMAL NOISE
1. Motor noise
2. Pump bearing running dry
3. Broken column bearing retainers
4. Broken shaft or oil tubing
5. Impeller dragging on bowl case
6. Cavitation, due to insufficient N.P.S.H.A. and/or
submergence
7. Foreign material in pump
8. Excessive fluid velocity in pipe system
H2: IMPELLERS
TROUBLE SOURCE PROBABLE CAUSE REMEDY
Wear on exit vanes and
shrouds
Abrasive action
Replace impeller if excessive. Consider coating or
upgrading material.
Pitting on entrance vanes of
impellers
Cavitation Correct condition or upgrade material to extend life.
Pitting on impellers and
bowl castings
Corrosion/Erosion
Investigate cost of different materials vs. frequency of
replacements.
Wear on impeller skirts and/
or bowl seal ring area
1. Abrasive action or excess wear impeller skirts to
function as bearing journal
2. Impeller set too high
1. Install new bearings and wear rings. Upgrade material
if abrasive action.
2. Re-ring and adjust impellers correctly.
Impeller loose on shaft
(extremely rare occurrence)
1. Repeated shock load by surge in suction or discharge
line (can loosen first or last stage impellers)
2. Foreign material jamming impeller (may break shaft or
trim over loads before impeller becomes too loose)
3. Differential expansion due to temperature
4. Parts improperly machined and/or assembled
5. Torsion loading on submersible pumps
1. Re-fit impellers. If collet mounted, consider changing to
key mounting.
2. Remove cause of jamming.
3. If collet mounted, consider change to key mounted.
Avoid sudden thermal shock.
4. Correct parts if necessary and refit.
5. Add keyway to collet mounting.