Goulds Pumps CV 3171 - IOM - Manual (Page 31)

CV 3171 IOM 05/11 31
TROUBLESHOOTING
Problem
Probable Cause Remedy
Pump not primed. No liquid in pit. Fill pit above casing. On dry
pit units, casing and suction pipe must be
completely filled.
Discharge head too high. Check total head, particularly friction loss.
Speed too low. Check motor speed.
Wrong direction of rotation. Check rotation.
Impeller, discharge pipe, strainer
completely plugged. Remove obstructions or backflush.
Suction pipe problems (where
applicable) Check suction lift, it may be too high. Line
may be plugged.
No liquid delivered.
Inadequate NPSH available. Check NPSH available and required.
Impeller, discharge pipe, or strainer
partially plugged. Remove obstructions or backflush.
Wrong direction of rotation Check rotation.
Discharge head higher than
anticipated. Check total head, particularly friction loss.
Worn or broken impeller. Inspect and replace if necessary.
Suction pipe problems (where
applicable) Check suction lift, it may be too high. Line
may be plugged.
Speed too low. Check motor speed.
Air or gasses in liquid. Increase submergence; rearrange piping to
prevent entrained air.
Pump not producing
rated flow or head.
Inadequate NPSH available. Check NPSH available and required.
Float controls misadjusted. Check float controls.
Air or gasses in liquid. Increase submergence; rearrange piping to
prevent entrained air.
Strainer plugged. Check sump for large items that the pump
may be picking up.
Pump starts then
stops running.
Air leak in suction line (where
applicable). Repair leak.
Improper alignment. Realign pump and driver. Bearings run hot.
Improper lubrication. Check lubricant for suitability and level.
Foundation not rigid. Tighten hold down bolts; stiffen foundation.
Improper pump/driver alignment. Align shafts.
Partially clogged impeller causing
unbalance. Backflush pump to clean impeller.
Binding, loose, broken rotating parts. Inspect and replace as required.
Bent shaft. Straighten or replace.
Worn bearings. Inspect and replace as required.
Discharge piping or suction piping not
anchored or properly supported. Anchor and support per Hydraulic Institute
standards.
Pump is noisy or
vibrates.
Pump is cavitating. Correct system problem.
Head lower than rating. Pump is
pumping too much liquid. Install throttle valve or trim impeller.
Liquid heavier than expected. Check specific gravity and viscosity.
Rotating parts binding. Check internal wear parts for proper
clearances.
Motor requires
excessive power
Speed too high Check motor.
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