Multistage water pump is a horizontal multi-stage centrifugal pump and suitable for transporting pure water and other liquids of both physical and chemical natures similar to those of pure water.
Here we analyze the failures and troubleshooting of multistage water pumps:
Failure: Pump not suck in, pointers of pressure gauge and vacuum meter severely jumping.
Causes: water injected into the pump insufficient, air leaks from water inlet pipe, meters etc.
Troubleshooting: Inject water into pump, tighten the leaking places.
Failure: pump not suck water, high vacuum shown on vacuum meter
Causes: foot valve not opened or blocked up, too big resistance with water sucking pipe, too high suck-in height.
Troubleshooting: correct or replace foot valve, clean or replace water sucking pipe, lower the height.
Failure: pressure available at pump outlet viewing from pressure gauge while no water out of pump.
Causes: too big resistance with water outlet pipe, wrong rotating direction, impeller blocked up, or pump damaged, insufficient r.p.m.
Troubleshooting: check or shorten outlet pipe, check motor, remove the pipe union, clean or replace impeller, raise r.p.m.
Failure: insufficient flow
Causes: pump blocked up, too much friction with seal ring, insufficient r.p.m.
Troubleshooting: clean pump and pipe, replace seal ring, raise r.p.m.
Failure: too big power the pump consumes
Causes: too tightly pressed packing gland, packing room heated, impeller worn out, water supply quantity of the pump increases
Troubleshooting: loosen packing gland or replace packing, replace impeller, increase resistance with outlet pipe to reduce the flow
Failure: abnormal sound inside of pump, no water into pump
Causes: too big flow, too big resistance inside of water sucking pipe, too high water-sucking height, aire gets in the water-sucking place, too high temperature of the liquid being transported
Troubleshooting: increase the resistance inside of water outlet pipe to reduce the flow, check water-sucking pipe and foot valve, lower the height, tighten the air leaking places.
Failure: pump vibrates
Causes: axes of pump and motor not on one central line, dirt or water gets into the bearing
Troubleshooting: align the two central lines, clean bearing, replace lubricating grease
Failure: bearing overheated
Causes: lubricating grease dried or dirty, axes of pump and otor not on one central line
Troubleshooting: check or clean bearing, replace lubricating grease, align the central lines
Failure: balancing water stops, balancing room heated, motor's power increased
Causes: pump runs under a big flow and low head, grinding occurs between balancing disk and board.
Troubleshooting: close outlet valve to the designed working condition, remove balancing disk for repairing
