Rten

I have read several postings here on the subject and am seeking additional information. I too have a pretty severe vibration that lasts 15-20 seconds after the pumps shuts off. I suspect a leaking check valve. I have a brass housing check valve that is mounted horizonally about 10 feet above the pump discharge. The system made some noise but got much worse after I replaced the sewer pump with a new Hydromatic SP-40 that has a pressure diaphram type cut off switch (same type pump as old one). I read here that installing a radiator hose could help isolate the vibration. I plan on replacing the 2 in check vlave with a new "quite-type" rubber flapper check valve. I have the following questions.

1. Should I mount the valve horizonally or in the vertical? (The pump manufacucture said mount it horizonally)

2. Do I need to drill a small 1/8 " hole in the discharge line just above the pump in the sump to prevent air cavatation?

3. Spring vs rubber flapper type valves? ( 1/2 psi required to open)

4. What about magnetic valves? ( a greater 2 psi required to open)

5. Best location for corregated radiator hose isolator?

6. Will putting the pump on a rubber base or feet really help?

7. How do I stop the vibration?

Thanks a Million..........."A big vibration with every flush".....Help

Redwood

I would install a new silent check on the vertical just above the pit with rubber couplings.

Radiator hoses belong under the hood of your car.

Rten

Thank you Redwood but are you also saying that I should not put a plumbing check valve under the hood of my car?............

Redwood

Yea I guess so....

Wuzzat?

What takes 15 to 20 seconds to wind down and
has enough stored energy [with no pump to feed it]
so as to cause a vibration [not just a noise]?

Can you post a YouTube video of the noise?

Is the vibration like the buzz of a fluorescent tube [120 Hz]?

Is it like the 10 Hz vibration of an ABS coming on because of slippery pavement?

Is the vibration of such an amplitude that you can see it?

Does holding onto pipes damp out the vibration?

A surgical rubber tube should do better in damping vibrations than a much-less-compliant radiator hose but I don't know if anyone makes a tube this large from surgical rubber.
As a prototype damper you could cut the ends off several long balloons and put one inside the other to make a resilient and strong tube, and clamp them to the more rigid piping. One balloon can withstand about 1/2 PSI and a 6' high pipe needs about 3 PSI to pump water out of it.

Rten

In my frenzy to find a solution to the vibration I would like to plead guilty to the charge of over estimating the length of the vibration. It is probably closer to 5-8 sec. The water in the pipe seems to be flowing backwards to the sewer pump as the pressure switch closes causing the low frequency vibration that agressively shakes the 2 inch pipe. Yes you can see and feel the pipe vibrate and hear it troughout the house. Another post suggested using a corragated radiator hose to isolate the vibration. I just got a Magic plastic spring loaded check valve that is advertised to reduce noise. Wish me luck.

Wuzzat?

It sounds like compliant pipe couplings cause the problem, but they may be there to solve other problems. Also, the pipe may just happen to be resonant at the vibration freq., so what starts out as a small amplitude shaking gets greatly magnified.

Since you can reliably reproduce the fault, use clamps or your hands to mechanically couple the pipe to a rigid surfaces. This should damp it out.
But watch out this doesn't overstress pipe joints, which would cause later failure due to fatigue.

Another way would be to isolate a vibrating section of pipe from the rest of the house using your patent pending party balloon isolation device [PPPBID].
You heard it here first!

But it might sell better if it had a German-sounding name.
This girl
http://www.oddcast.com/demos/tts/tts_tran_example.php?clients
tells me it translates to
dieser Erfindung ist dumm

but she has lied to me before.

Redwood

One of these would be what you need to use...



This is a plumbing fitting...
Not a radiator hose...
Not surgical tubing...
A Plumbing Fitting...

Wuzzat?

Those Fernco couplers are pretty stiff.

I had something in mind more like the coupler on page 14 of
http://www.thevmcgroup.com/PDFs/vmcspec.pdf

"Series "VMS" and "VMT"
Quiet-Sphere Flexible Connectors
Single-sphere (VMS) and twin-sphere (VMT) connectors are
molded of neoprene and synthetic fiber and furnished with
corrosion resistant floating steel flanges. Operating temper-
ature to 240°F and operating pressure to 214 psi.
Compensates for expansion, compression, transverse
movement, and angular deflection. Reduces vibration and
noise transmission. Size 1-1⁄4" to 20" I.D. "

if somebody makes a residential version of this coupler.

The graph on page 2 of the link shows the dependence on frequency.

kok328

Install a rubber flapper check valve no more than 2ft. from the pump on a vertical portion of the discharge pipes. The rubber check valve is similar material as a Fernco coupler and will do just fine in reducing vibration. The reason for your vibration is related to the location of your existing check valve, the material construction of your existing check valve and the horizontal installation of your existing check valve.