BLACKMER SYSTEM ONE, Инструкции по установке, эксплуатации и обслуживанию

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1301-C00 Page 51/56
14.0 TROUBLESHOOTING
Pump Does Not Deliver Liquid

Pump not primed

Pump suction pipe not completely filled with liquid

Insufficient available NPSH

Air pocket in suction line

Inlet of suction pipe insufficiently submerged

Pump operated with closed or partially closed suction
valve

Clogged suction strainer

Obstruction in suction line

Clogged impeller

Speed of pump too low

Wrong direction of rotation

Impeller diameter smaller than specified

Static head higher than shut-off head

Total head of system higher than design of pump

Parallel operation of pumps unsuitable for this purpose

Viscosity of liquid differs from design conditions
Insufficient Capacity Delivered

Pump suction pipe not completely filled with liquid

Insufficient available NPSH

Excessive amount of air or gas in liquid

Air pocket in suction line

Air leaks into suction line

Air leaks into pump through mechanical seal

Inlet of suction pipe insufficiently submerged

Vortex formation at suction

Pump operated with closed or partially closed suction
valve

Clogged suction strainer

Obstruction in suction line

Excessive friction losses in suction line

Clogged impeller

Two elbows in suction piping at 90° to each other,
creating swirl and prerotation

Speed of pump too low

Wrong direction of rotation

Uncalibrated instruments

Impeller diameter smaller than specified

Friction losses in discharge higher than calculated

Total head of system higher than design of pump

Viscosity of liquid differs from design conditions

Foreign matter in impellers
Insufficient Pressure Developed

Excessive amount of air or gas in liquid

Air leaks into suction line

Air leaks into pump through mechanical seal

Inlet of suction pipe insufficiently submerged

Vortex formation at suction

Pump operated with closed or partially closed suction
valve

Clogged suction strainer

Obstruction in suction line

Excessive friction losses in suction line

Clogged impeller

Two elbows in suction piping at 90° to each other,
creating swirl and pre-rotation

Speed of pump too low

Wrong direction of rotation

Uncalibrated instruments

Impeller diameter smaller than specified

Specific gravity of liquid differs from design conditions

Viscosity of liquid differs from design conditions

Foreign matter in impellers
Pump Loses Prime After Starting

Pump suction pipe not completely filled with liquid

Excessive amount of air or gas in liquid

Air leaks into suction line

Air leaks into pump through mechanical seal

Source of sealing liquid has air in it

Inlet of suction pipe insufficiently submerged

Vortex formation at suction
Excessive Power Consumption

Pump speed too high

Impeller diameter larger than specified

Binding rotating element

Impeller rubbing the casing or backcover

Bent shaft

The mechanical seal binding

Specific gravity higher than anticipated

Viscosity higher than anticipated

Solids concentration higher than anticipated (Vortex only)

The pump and driver shafts misaligned

Wrong direction of rotation

Uncalibrated instruments

Total head of system higher than design of pump

Total head of system lower than design of pump

Running pump at too high a flow

Foreign matter in propeller

Misalignment
Cavitation

Insufficient suction head available (NPSHA)

Operating at a higher capacity than specified

Excessive air or gas entrainment

Vortexing in the pump suction or intake system

Liquid temperature higher than the vapor temperature

Air leak in the pump or suction line

Partially plugged suction

Elbow too close to the pump suction

Temperature too low, thereby increasing liquid viscosity