On Mar 12, 10:31 am, "
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).

Illegal in many communities and just a bad practice generally.

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?

From a simple physics analysis, one could asume you're pumping into a
closed system which then relieves the pressure through the check
valve. Confirm by allowing the pump to discharge at atmospheric
pressure, i.e., out onto your lawn or into a (legal) storm sewer. The
water can't all drain, so some will return to the check valve and you
will hear a single bang as it closes, then nothing further.
if this cenario works, that will tell you how to modify the system for
better peac and quiet. Good luck.

Joe