MAS EN ENM 300-550, Руководство по эксплуатации

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Mas Grup
9
10. POSSIBLE FAILURES, CAUSES, SOLUTIONS
Possible failures and solution strategies are listed in the table below. Please apply to the Customers’ Service Department of our company when a
generic solution is not found to your problem.
While the failures are repaired the pump must always be dry and un-pressurized.
POSSIBLE FAILURE CAUSES SOLUTIONS
The pump delivers insufficient
capacity

Discharge head too high

Very high counter pressure

Pump and/or pipe cannot discharge air, cannot suck

Occurrence of air pockets inside the pipe

NPSH is too low

Readjust the operating point

See if there is any undesired material inside
the pipe

Vent completely the pump and the pipe

Change the piping configuration

Increase the liquid level
Motor overload

System pressure is lower than the requested pressure level

Speed too high

Liquid pumped of different specific gravity and viscosity than
that for which pump is rated

Engine works at two phases

Adjust the operating pressure to the label
value

Decrease the speed

Increase the engine power

Replace the fuse and control the electrical
connections
Pump head is too high

System pressure is higher than the requested pressure level

Set the operating pressure to the label value.
Bearing temperatures are high

Worn out coupling

Too much, too little or improper lubrication

Increase in axial forcing

Replace the coupling

Change the oil, decrease or increase its
quantity

Clean the balance holes on the impeller disc
Excessive leakage from the
stuffing box

Worn out gland

Loose gland

Use brand new gland

Change the stuffing bush

Tighten the gland nuts
Noisy operation

Worn out motor or pump ball bearings

Cavitation

Worn out or misaligned coupling

Operation in the far left or right of the performance curve

Replace

Close the delivery partially in order to reduce
the capacity.

Replace the coupling or align it

Operate the pump at its label setting
Excessive increase in pump
temperature 
Pump and/or pipe can neither discharge, nor aspirate air

Too low capacity

Bleed completely the pump and the pipe

Open more the valve
Vibration

Pump and/or pipe can neither discharge, nor aspirate air

NPSH is too low

Internal components of the pump are worn out

System pressure is lower than the requested pressure level

Coupling is misaligned

Too much, too little or improper lubrication

Rotor unbalanced

Improper bearings

Bleed completely the pump and the pipe

Increase the liquid level

Replace the worn out components

Adjust the operating pressure to the label
value

Align the coupling

In case of continuous overload, decrease the
impeller diameter

Change the oil, decrease or increase its
quantity

Balance the impeller again

Use new bearings
Table 2 - Possible Failures, Causes, Solutions