Pump motor running but not pumping much water

[daver]

I have a SmartPond 2100 GPH pump that has worked great for 5 years. But, suddenly this morning, the water flow-rate dropped to about 10 % of normal. I can hear and feel the pump motor running, but little water is moving. The pump is in the skimmer. I made sure it was clear of any debris, but nothing changed. What could be causing this problem?

The kidney-shaped pond measures 14'x7'x2.5' deep, with a 2' high waterfall. I figure it's about 700-800 gallons. Does a 2100 GPH pump sound about right, or should I drop back to about a 1200 GPH pump if I need to replace it?

Thanks,
Dave

 

[combatwombat]

You might need to open it up and check the impeller. Might be full of gunk or broken.

I’d stick with a 2000 GPH pump if you need to replace. You’re probably getting closer to 1500 after factoring head loss, whichis right about where you’d want to be.

 

[daver]

You might need to open it up and check the impeller. Might be full of gunk or broken.

I’d stick with a 2000 GPH pump if you need to replace. You’re probably getting closer to 1500 after factoring head loss, whichis right about where you’d want to be.

Thanks for your quick reply. Sorry for my delayed response. I just returned home from a short trip. The impeller will be my first target when I open it up, if gunk isn't the problem. Good luck with your new project. Hope you have a big shovel. Ha!

 

[poconojoe]

If it's not the impeller, maybe air has gotten trapped in the pump.

Could be a plumbing leak where air is getting sucked in.
Or, if your pump stopped and restarted it may have taken in some air. That has happened to me, where I pull my pump and when I drop it back in it doesn't pump because air got trapped in it. It's almost like it needed to be primed.
Or, has the pond water level dropped allowing the pump to suck in air?