I have a Sta-Rite Max E-Pro Centrifugal 1 HP Pump (exact model unknown, I will look tonight) that, over the past few weeks, has been getting much louder and now is extremely loud and has an almost rattling sound coming from the motor area. After running for a few mins, the motor section is pretty hot to the touch on the top, but not on the sides or bottom.
Last night, I ripped the pump apart to look at the impeller, which appears to be fine. There is little, to no air, getting into the pump basket as it is fully primed with no air bubbles. It does seem to take a little a longer to get fully primed than I remember, though that could be my imagination.
Ever since I started using it (I bought the house this September), when it is turned on, it makes a quick 1-2 second loud humming noise then kicks on and starts pumping water. After I took the pump apart yesterday and reassembled it, it now makes 4-5 second loud humming noise and sometimes kicks on and sometimes shuts off completely (I'm assuming some type of internal shut-off is occurring).
The pump sits on the concrete slab in my garage, but is not bolted down. I've tried pushing down on it to simulate bolting, but it does nothing to the noise level.
I'm thinking its the bearings, but is there anything else that could be causing this? I've heard a capacitor could be at fault, but why would that make the terrible rattling noise?