Flowserve LR Worthington - Manual (Page 34)

LR, LRV, LLR and LR-S USER INSTRUCTIONS ENGLISH 71569088 08-10
Page 34 of 48 flowserve.com
h) Torque up seal cover screws [6570.3] and check
shaft/sleeve does not rub in seal cover or stationary
seal seat bore. Ensure any spare holes in
mechanical seal cover, particularly on cartridge
mechanical seals, have sealing plugs fitted.
i) If gland packing is fitted, pack the gland, ensuring
that the cut ends in each ring are staggered by
120 degrees.
j) The glands are packed as shown in section 8.2.
Finger tighten gland nuts.
k) Add the same grease as used on the bearings
under the lips of the inboard and outboard shaft
seal rings [4305] and slide up to bearing cover and
bearing housing faces to give light contact.
l) Pipe up any external auxiliary connections.
m) Check for free rotation.
7 FAULTS; CAUSES AND REMEDIES
FAULT SYMPTOM
P u m p o v e r h e a t s a n d s e i z e s
⇓ ⇓ ⇓ ⇓ ⇓ ⇓ ⇓ ⇓ B e a r i n g s h a v e s h o r t l i f e
⇓ ⇓ ⇓ ⇓ ⇓ ⇓ ⇓ ⇓ P u m p v i b r a t e s o r i s n o i s y
⇓ ⇓ ⇓ ⇓ ⇓ ⇓ ⇓ ⇓ M e c h a n i c a l s e a l h a s s h o r t l i f e
⇓ ⇓ ⇓ ⇓ ⇓ ⇓ ⇓ ⇓ M e c h a n i c a l s e a l l e a k s e x c e s s i v e l y
⇓ ⇓ ⇓ ⇓ ⇓ ⇓ ⇓ ⇓ P u m p r e q u i r e s e x c e s s i v e p o w e r
⇓ ⇓ ⇓ ⇓ ⇓ ⇓ ⇓ ⇓ P u m p l o s e s p r i m e a ft e r s t a r t i n g
⇓ ⇓ ⇓ ⇓ ⇓ ⇓ ⇓ ⇓ I n s u f f i c i e n t p r e s s u r e d e v e l o p e d
⇓ ⇓ ⇓ ⇓ ⇓ ⇓ ⇓ ⇓ I n s u f f i c i e n t c a p a c i t y d e l i v e r e d
⇓ ⇓ ⇓ ⇓ ⇓ ⇓ ⇓ ⇓ P u m p d o e s n o t d e l i v e r l i q u i d
⇓ ⇓ ⇓ ⇓ ⇓ ⇓ ⇓ ⇓
PROBABLE CAUSES POSSIBLE REMEDIES
A. SYSTEM TROUBLES
Pump not primed. Check complete filling.
Pump or suction pipe not completely filled with
liquid.
Check and complete filling.
Suction lift too high or level too low.
Check NPSH
A
>NPSH
R
, proper submergence,
losses at strainers and fittings.
Excessive amount of air or gas in liquid. Check and purge from pipes.
Air or vapour pocket in suction line. Check suction line design for pockets.
Air leaks into suction line. Check airtight pipe then joints and gaskets.
Air leaks into pump through mechanical seal,
sleeve joints, casing joint or pipe lugs.
Check airtight assembly then joints and gaskets.
Foot valve too small. Investigate replacing the foot valve.
Foot valve partially clogged. Clean foot valve.
Inlet of suction pipe insufficiently submerged. Check cut out system design.
Total head of system higher than differential head
of pump.
Check discharge head and head losses in
discharge pipe at the valve settings. Check back
pressure is not too high.
Total head of system lower than pump design
head. Throttle at discharge valve or ask Flowserve if the
impeller can be trimmed.
Specific gravity of liquid different from design. Consult Flowserve.
Viscosity of liquid differs from design. Consult Flowserve.
Operation at very low capacity. Measure value and check minimum permitted.
Operation at high capacity. Measure value and check maximum permitted.