Instruction and Operation Manual
56
Situation/Symptom
Possible Cause
Investigative/Corrective Action
Diffuser discharge throat partially plugged or
impeller damaged by passage of a solid particle.
Clean these areas of all obstructions and restore
surfaces to a smooth polished finish free of all
corrosion pitting. Edge of diffuser throat must be
sharp.
Corrosion and/or erosion of diffuser throat (may
also be accompanied by corrosion/ erosion of
diffuser and cover surface adjacent to impeller).
If edge of throat is no longer sharp and smooth
or has opened in size, head-rise may be
reduced. Opening of the inlet area of the throat
will result in higher flow rate and horsepower
consumption. Corrosion/erosion of diffuser and
cover surfaces will result in a significant
horsepower increase.
Excessive recirculation from discharge to inlet.
Check flow through external plumbing.
Pump o-ring (936C) damaged or missing.
Integral centrifugal separator orifice worn.
Process fluid specific gravity or viscosity different
from values shown on specification sheet.
Check actual viscosity and specific gravity at
operating temperature. Viscosity higher than five
centipoise will cause reduced head and flow and
increased power consumption.
Driver speed too low.
Check speed against value listed on
specification sheet.
Insufficient total head
cont.
Pressure gauges or flow meters in error
Calibrate instrumentation.
Fluid specific gravity or viscosity higher than values
listed on specification sheet.
Check actual viscosity and specific gravity
against value listed on specification sheet.
Electrical failure in electric driver.
Check circuit breaker heater size and setting.
Check voltage and voltage balance between
phases.
Current for each phase should be balanced
within three percent.
Mechanical failure in driver, gearbox or pump.
Remove driver and check for freedom of rotation,
correct spacing
of pump and gearbox shaft assemblies.
Remove fluid end and search for any mechanical
failure.
Remove gearbox oil level sight glass and inspect
bottom of sump for wear particles. Bearings are
probably not damaged if no wear particles are
present.
Driver overloaded.
Corrosion pitting on surface of diffuser cover or
diffuser, adjacent to impeller blades. Head rise is
also reduced by this condition.
Disassemble pump and inspect. Rough or
pitted surfaces can cause friction losses which
will significantly increase horsepower
consumption. Clean these areas of all
obstruction and restore surfaces to a smooth
polished finish. Check diffuser throat area at
the inlet; erosion or corrosion resulting in
roughness or increased area will increase
horsepower consumption. Note: A larger throat
size than design will allow a higher flow and
horsepower for a given head rise.
Flow rate too low.
Increase flow rate through pump. Add bypass to
suction tank if necessary.
Insufficient NPSH available.
Refer to solution for insufficient NPSH under “No
flow, no pressure at startup,” above.
Excessive discharge
pressure pulsations.
Defective flow control valve.
Check control valve.
Summary of Contents for LMV-313
Page 1: ...SUNDYNE LMV 313 PUMPS Instruction and Operation Manual August 2007 ...
Page 36: ...Instruction and Operation Manual 32 Figure 15 Inducer Housing Shim Adjustment ...
Page 40: ...Instruction and Operation Manual 36 Figure 17 Service Check Points ...
Page 69: ...Instruction and Operation Manual 65 Figure 22 Gearbox Components ...
Page 70: ...Instruction and Operation Manual 66 Figure 23 Pump Nomenclature ...
Page 71: ...Instruction and Operation Manual 67 Figure 24 Exploded View ...
Page 72: ...Instruction and Operation Manual 68 Shaft Assemblies Figure 25 Shaft Assemblies ...
