Flowserve DMX - Manual (Page 47)

DMX/DMXD/DMXH/DMXDH USER INSTRUCTIONS ENGLISH 85392728 - 10/09
Page 47 of 60
7 FAULTS; CAUSES AND REMEDIES
FAULT SYMPTOM
Pump overheats and seizes
⇓ ⇓ ⇓ ⇓ ⇓ ⇓ ⇓ ⇓ Bearings have short life
⇓ ⇓ ⇓ ⇓ ⇓ ⇓ ⇓ ⇓ Pump vibrates or is noisy
⇓ ⇓ ⇓ ⇓ ⇓ ⇓ ⇓ ⇓ Mechanical seal has short life
⇓ ⇓ ⇓ ⇓ ⇓ ⇓ ⇓ ⇓ Mechanical seal leaks excessively
⇓ ⇓ ⇓ ⇓ ⇓ ⇓ ⇓ ⇓ Pump requires excessive power
⇓ ⇓ ⇓ ⇓ ⇓ ⇓ ⇓ ⇓ Pump loses prime after starting
⇓ ⇓ ⇓ ⇓ ⇓ ⇓ ⇓ ⇓ Insufficient pressure developed
⇓ ⇓ ⇓ ⇓ ⇓ ⇓ ⇓ ⇓ Insufficient capacity delivered
⇓ ⇓ ⇓ ⇓ ⇓ ⇓ ⇓ ⇓ Pump does not deliver liquid
⇓ ⇓ ⇓ ⇓ ⇓ ⇓ ⇓ ⇓ PROBABLE CAUSES POSSIBLE REMEDIES
A. SYSTEM TROUBLES
Pump not primed. Check complete filling. Vent and/or prime.
Pump or suction pipe not completely filled
with liquid.
Suction lift too high or level too low. Check NPSHa>NPSHr, proper submergence, losses at
strainers and fittings
Insufficient margin between suction pressure
and vapor pressure.
Excessive amount of air or gas in liquid. Check and purge pipes and system.
Air or vapor pocket in suction line. Check suction line design for vapor pockets
Air leaks into suction line. Check suction pipe is airtight.
Air leaks into pump through mechanical seal,
sleeve joints, casing joint or pipe plugs. Check and replace faulty parts.
CONSULT FLOWSERVE.
Inlet of suction pipe insufficiently submerged. Check out system design
Speed too low. CONSULT FLOWSERVE.
Speed too high. CONSULT FLOWSERVE.
Total head of system higher than differential
head of pump. Check system losses.
Remedy or CONSULT FLOWSERVE.
Total head of system lower than pump design
head.
Specific gravity of liquid different from design. Check and CONSULT FLOWSERVE.
Viscosity of liquid differs from that for which
designed.
Operation at very low capacity. Measure value and check minimum permitted.
Remedy or CONSULT FLOWSERVE.
Operation at high capacity. Measure value and check maximum permitted.
Remedy or CONSULT FLOWSERVE.
Suction pressure too low, Foreign material in
suction line. Open suction valve, Check power supply to correct voltage,
Dismantle suction line remove foreign material.
B. MECHANICAL TROUBLES
Misalignment due to pipe strain. Check the flange connections and eliminate strains using
elastic couplings or a method permitted
Misalignment due to improper pump/driver
setup. Check alignment and correct as necessary.
Improperly designed foundation. Check setting of baseplate: tighten, adjust, grout base as
required.