I have installed a new sump pump and at the end of the water discharge it makes a thumping sound. The pump is a 3/4 hp. flotec sump pump. I have a flotec "Anti-air locking" check valve
install directly into the discharge outlet and another flotec check valve installed about 3'-4' up in the discharge line.

When I disconnect the rubber clamp from the check valve in the discharge line I can hear air being released. I'm thinking the reason why the thumping is occurring is that there is air still in the line between the discharge line valve and the valve that is screwed into the pump outlet!

I would appreciate any help or thoughts on this matter.

Thanks,

 

This is probably the same problem I'm having with my sump pump. I'm guessing it's due to what is commonly called "water hammer." This is caused by the momentum of the moving water either physically moving the pipe where it strikes something (i.e. the wall or loose mounting bracket) or a flex of the pipe (think a quick bulge outwards and then it snaps back) due to a pressure wave created by suddenly stopping one end of the water (at the pump) while the rest tries to continue flowing (due to the water's momentum). See www.factsfacts.com/MyHomeRepair/PipeNoises.htm for more info. Maybe you can get a "water hammer arrestor" that is essentially an air chamber behind a piston connected to your pipe (after the check valve) that absorbs the momentum of the water more slowly than would the flexing pipe.

Or then again, you could just have a noisy check valve... Think: while the water is flowing, the check valve is open. When the pump stops, the water tries to flow back down the pipe and the check valve flap slams closed...

Hope this helps.

Paul

 

Click on the link and look for the Troubleshooting Section>Sump Pump.
A friend of mine had to drill a small hole in the PVC line to eliminate his noise. (diagonal drill hole)
http://www.flotecpump.com/

They also make spring loaded check valves that eliminate the water hammer noise.

BTW, which Flotec do you have? Is it the Floodmate 7000?
How do you like it? I'm getting ready to buy one at Sears.
I originally wanted to replace my Hydromatic with the same one but my local plumbers will not sell it to me because I'm not a licensed plumber.

 

MSA, I have the new Flotec model FPSC4550A, it is a 3/4 h.p.. I think the pump works fine, but I am going to return it to Home Depot. The the pump is more than I need and I believe it is contributing to the thumping in my pipes I am presently experiencing. I am going to purchase a Hydromatic pump. I like the vertical switch that the Flotec has and the Hydromatic uses a similar switch, model VS33A.

In your reply you say you are changing from a Hydromatic to a Flotec. What can you tell me about the Hydromatic pump. I had the same problem you had with purchasing the pump, so I found a distributor in Tennessee who ordered the pump from the manufacturer and they are going to ship it directly to me.

 

The Hydromatic has been great for me until the switch went out. Made of cast iron so it stays put in the sump liner.
I ended up replacing the switch and getting a new check valve and all is fine. (Very inexpensive)

I wanted to replace the whole unit with a Hydromatic but I needed to be a licensed plumber in order to get one.
Thats when I saw the top of the line Flotec that could be purchased by a residential homeowner. It pumped way more than the Hydromatic and that it had a lifetime warranty.
That might just be overkill as you stated.
So 9 years later and a heavy rainstorm with my new switch and check valve and all is fine with the Hydromatic.