UB USER INSTRUCTIONS ENGLISH 71569247
®
7 FAULTS; CAUSES AND REMEDIES
FAULT SYMPTOM
Pump overheats and seizes
⇓Bearings have short life
⇓ Pump vibrates or is nois y
⇓ Mechanical seal has short life
⇓ Mechanical seal leaks excessi vel y
⇓ Pump requires excessive power
⇓ Pump loses prime after starting
⇓ Insuffi cient pressure developed
⇓ Insuffi cient capaci t y delivered
⇓ Pump does not deliver liquid
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| ⇓ | PROBABLE CAUSES | POSSIBLE REMEDIES |
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| A. SYSTEM TROUBLES | |
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| z | Pump not primed. | Check complete filling. |
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| z | z | Pump or suction pipe not completely filled with | Check and complete filling. |
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| liquid. |
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| z | z | Suction lift too high or level too low. | Check NPSHA>NPSHR, proper submergence, |
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| losses at strainers and fittings. | ||||||
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| Excessive amount of air or gas in liquid. | Check and purge from pipes. |
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| z | z | Air or vapour pocket in suction line. | Check suction line design for pockets. |
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| Air leaks into suction line. | Check airtight pipe then joints and gaskets. |
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| Air leaks into pump through mechanical seal, | Check airtight assembly then joints and gaskets. |
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| sleeve joints, casing joint or pipe lugs. | |||
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| Foot valve too small. | Investigate replacing the foot valve. |
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| Foot valve partially clogged. | Clean foot valve. |
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| z | z | Inlet of suction pipe insufficiently submerged. | Check cut out system design. |
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| z | z | z | Total head of system higher than differential head | Check discharge head and head losses in |
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| discharge pipe at the valve settings. Check back | ||||
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| of pump. | |
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| pressure is not too high. | |
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| Total head of system lower than pump design | Throttle at discharge valve or ask Flowserve if the |
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| head. | impeller can be trimmed. | |
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| Specific gravity of liquid different from design. | Consult Flowserve. |
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| Viscosity of liquid differs from design. | Consult Flowserve. |
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| Operation at very low capacity. | Measure value and check minimum permitted. |
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| Operation at high capacity. | Measure value and check maximum permitted. |
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| B. MECHANICAL TROUBLES | |
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| Misalignment due to pipe strain. | Check the flange connections and eliminate |
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| strains using elastic couplings or a method | |||||||
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| permitted. |
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| Improperly designed foundation. | Check setting of baseplate: tighten, adjust, grout |
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| base as required. | ||
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| Shaft bent. | Check shaft runouts within acceptable values. |
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| Rotating part rubbing on stationary part internally. | Check for signs of this and consult Flowserve if |
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| necessary. | |||||
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z | z | z | z | z | z |
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| Bearings worn | Replace bearings. |
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| Wearing ring surfaces worn. | Replace worn wear ring/surfaces. |
Page 27 of 32