I recently adjusted a shellback pump in a basement laundry tub that was not emptying completely. The adjustment work perfectly. When the tub has water in in and it empties completely it shuts off and makes several bangs. If you operate the pump on and off with plenty of water in the system it is quiet? I was thinking the water in the vertical pipe after the checkvalve was bouncing against the checkvalve and maybe a hammer arrester on the vertical pipe would work, any thoughts are appreciated!
Thanks mike

Hi Mike

Did the pump/drain make this noise before the adjustment? Did you disassemble the pipes when you made the adjustment? Let us know...

Mark

No noise prior to the pump adjustment, to adjust the shellback it just twisting out a small copper tube that senses the water so no pressure changes.ThanksMike

No pipe changes either

If the noise didn't happen before the adjustment then the problem shouldn't be something that can be fixed by adding a hammer arrestor or anything else to the system, right? In this case, I am guessing that the check valve is getting hung up on its internal parts or some sediment/debris, or it could just be that the check valve is old/deteriorating. It could also be that you just never noticed the noise before... you'd be surprised by how many people say this is the case in the long run!

I'd start at the check valve... remove/inspect, maybe replace?

Your thoughts?