Polaris TBM 200 LH - Manual (Page 17)

INSTALLATION, OPERATION AND MAINTENANCE MANUAL
POLARIS - SERIES TBM 200 LH ( 8” ) - TYPE PHO / PBO / PVO
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DOCUMENT NBR. : PED-010 REVISION: 1 EFFECTIVE
DATE: 08-24-2004
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PUMP IS EXPECTED TO STOP BUT KEEPS RUNNING
If the pump has been running satisfactory and is capable of emptying the
sump to the control stop level, check for leakage in discharge piping and
connections. Leakage water may be re-circulated back into the sump.
Check that the impeller or suction is not clogged.
CAUTION: Disconnect and lock out the main power supply before working in
the intake area of the pump. Failure to do so can result in serious injury.
Clean out and remove any objects that may have clogged the impeller and
inspect the pump components for any visual damage. Inspect the sump area
and remove any oversized material and debris. Inspect pump strainer for
excessive wear and replace if required.
Check that the impeller and casing are not worn and need to be replaced.
Check the impeller running clearance and adjust as required.
Check for faults in the level control equipment. Clean and inspect the level
sensor probes and perform a function test. Check the level control relay
contactor and holding circuit. Replace any faulty components. Check the
location of the stop level probe to ensure it is not set too low.
- PUMP STARTS AND STOPS REPEATEDLY
Check if the back flow from the discharge pipe is enough to raise the sump
level to the level-controller starting probe. If so, positioning a rubber flap valve
in the discharge pipe close enough to the pump will minimize back-flow.
Check that the distance between start and stop level probes is not too short.
Check that the contactor does not break its self-holding function. Check the
voltage in the control circuit in relation to the rated voltage on the coil. Check
the functioning of the stop sensor probe. The voltage drop in the line during
the start-up surge can cause the contactor self-holding function to break.