Pumps

1Q. What is the best way to understand why a pump isn't pumping?

1A. Make sure it isn't something simple like the pump operating backwards because it was wired up wrong, or the pressure gage is bad. For more complex problems you need to know something about pump and system curves to understand the effect of many of the variables. Did you know that if several pumps are pumping into the same header, the stronger pump can back out (shut out) the weaker pumps?

2Q. We have a multi-stage vertical turbine pump that has been repaired because of corrosion and now keeps failing. They had been running three or four years before needing repairs. Any ideas?

2A. When putting these type pumps back together everything has to be done correctly. If things aren't aligned correctly, balanced correctly, clearances set correctly, shafts straight, then bushings will wear and wrecks will occur. Have an experienced machinist go to the shop and follow and record the repair details closely.

3Q. We have a centrifugal pump that trips the motors overload and the unit Electrician said the motor is OK but just pulling a lot of amps. Should we get a bigger motor?

3A. If the motor and pump turn freely when shut down, meaning nothing is binding, I think I would check the flow controls first. You may be pumping at the end of the pump curve which would be off design, and require more horsepower, meaning amps. If you don't need all that flow you may be able to trim the impeller. Check with the Operations people first.