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SP-LR Self-Priming Liquid Ring Pump Troubleshooting

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    SP-LR Pump

    Pomac Pumps’ SP-LR Pump is a Self-Priming Liquid Ring Pump that has been designed to meet EHEDG specifications for use in food-grade and other hygienic applications.


    What are the main malfunctions and problems with the SP-LR Sanitary Self-Priming Liquid Ring Pump? 

    A malfunction in a pump system may be caused by various reasons and is not necessarily the pump itself. Issues with the pipework or other fluid accessories within the system can be contributing factors. Furthermore, if the operating conditions differ too greatly from the provided specification for which the pump was selected for can also be a major contributing factor.

    Consequently, it is always recommended to check the following first:

    • Has the pump been installed correctly?
    • Are the operating conditions still according to the initial specification?
    • Are the other fluid accessories within the pipework functioning correctly?

    In general, the following malfunctions can be identified:

    1. Pump provides little or no flow
    2. Pump does not reach duty point
    3. Pump provides irregular flow
    4. Pump leaks
    5. Pump vibrates excessively
    6. Pump makes too much noise
    7. Motor overheats
    8. Motor cuts out on thermal overload
    9. Pump has seized

    Below is a table of the possible causes and solutions of these malfunctions.

    MalfunctionCause Action
     X   XX  electrical connection defectiveHave qualified electrician check the electric connections
     X       wrong rotation directionHave qualified electrician reverse the sense of rotation of the electric motor
    XXX  X   insufficient pre-pressureIncrease the pre-pressure or place the pump on a lower position
     X     X pump operating at the wrong speedCheck the motor speed
            Xcontaminations or objects in the pumpClean the pump, if necessary disassemble
    XXX      air in the pipingInspect the piping
     X       valve in suction pipe is not completely openEntirely open the valve in the suction pipe
     X       pump selected with too small delivery headInstall another pump
    XXX     Xsuction pipe or filter blockedClean the suction pipe or the filter
       X     shaft seal defectiveDisassemble the pump and replace the shaft seal
       X     O-ring seal defectiveDisassemble the pump and replace the O-ring seal
           X liquid temperature is too highDecrease the liquid temperature
    X      XXimpeller is jammedDisassemble the pump and replace the impeller
        XX XXimpeller is damagedDisassemble the pump and replace the impeller
        XXXXXmotor shaft is bentReplace the motor
        XXXXXextension shaft is looseDisassemble the pump, inspect the extension shaft, reassemble it and readjust.
        XXXXXbearings are damaged or wornReplace the motor. For IG(F): replace the bearings
           XXmotor is overloadedCheck the viscosity of the liquid.
    Switch off the motor and check if the pump does not drag. If so, disassemble the pump and repair it

    Inspection & Maintenance Schedule

    Routine inspection and maintenance can avoid unnecessary and expensive downtime as well as operating costs. It is recommended to check the following on a daily basis:

    • That the valve in the suction pipe is completely open
    • That the inlet pressure is not too low in order to avoid the occurrence of cavitation
    • The delivery pressure is in line with system requirements
    • That the shaft seals are not leaking.
    • Pressure and Flow of the flushing system, if present
    • The temperature of the heating/cooling system, if present

    For IG & IGH Variants periodically check the bearing oil levels. The oil must be changed annually or after every 5000 operating hours.

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