Worn Impeller?

[Crystal]

Can a worn impeller and diffuser (30 years old on Pentair Challenger pump) give the same symptoms of an air leak in the suction line? The impeller is not clogged or obviously broken, but living in the desert it has seen a lot of sand through it.

Without vacuum attached it pulls water ok, but with vacuum attached and increased suction needed the pump basket is starved for water and water is pulled in at a low unsteady rate (a decent pull of water, then down to trickling, then back to a decent pull, then back down to barely pulling water) as seen through pump basket.

 

[mas985]

A worn impeller or diffuser would not leak air since neither is exposed to air. The most likely locations for air leaks are the pump lid seal and the suction side drain plug. These types of leaks get worse when the pump is under higher suction such as when a cleaner is attached. Silicon pool lube can help seal both.

 

[Crystal]

I have changed and lubricated all the gaskets and even changed out the shaft seal on the motor. No water squirts when pump is turned off to point toward a leak and shaving cream around joints did not indicate anything that could be seen.

Why I was thinking the motor was weak or impeller not working properly and it wasnt an air leak is because air bubbles do not pour out return lines, but this may be because of loss of pressure water isn't traveling that far.

 

[mas985]

Is your filter pressure lower than normal or the flow rate strength out of the returns weaker than normal?

If yes, then it could be a clogged impeller. That can prevent a complete prime of the pump so it appears as though there is an air leak. Remove the pump basket and reach into the impeller inlet and see if there is any debris there.