" wrote:

Hello, quick question for the experts out there. I live in the
midwest and have a sump pump in the basement. PVC from sump pump runs
up the basement wall and across a 10 foot ceiling section and connects
directly to the city sewer system underground (I think).

Our sump had been making a BANGING noise at the end of each cycle.
Reading up about that, I determined it must be a bad check valve.
Replaced that myself. Still a lot of vibration. Had a plumber come
out...he recommended a new sump pump as our home is 12-years old.
Plumber installed that, and told me to secure the ceiling PVC better
to remove vibration. Winter came and I forgot about it. ;(

Now that we've had some thaws, vibration came back worse than ever. I
got some hangers and secured the PVC as solid as possible. Now, the
vibration is localized to the check valve, and it lasts like 30-45
seconds after the pump cycles. No banging, just loud vibration.

I had saved the original check valve, which the plumber had said was
still good. I put that back on, and all was quiet, until I noticed it
was leaking around the upper rubber flanges. I tightened it down and
now it's the same...massive vibration localized to the check valve
after a cycle, lasting around 30-45 seconds.

Any ideas what's happening?

Be sure you have a small hole drilled in the sump discharge pipe to
prevent air lock.

http://store.waterpumpsupply.com/supuinpr.html

"Drill a relief hole (1/8" or 3/16" diameter) in the discharge pipe.
This hole should be located below the floor line between the pump
discharge and the check valve. Unless such a relief hole is provided a
bottom intake pump could "air lock" and will not pump water even though
it will run."