Installed new submersible sump pump. The old one had no check valve, so added one as well. Now, when the pump stops, there’s a loud, repeated hammering, in the pipe, reaching what sounds like a lawn mower. This lasts about 10-15 seconds.
I would have thought once the check valve closes, there might be just one big thud, not several faster hammering.
Any thoughts on this very loud problem would be quite welcome.
regards, Carl
Replies
Is it possible that you have the check valve too high up above the sump and there is so much water in the pipe below the valve that it falls back into the sump and momentarily turns the pump back on?
c valve was installed below first el, at the rim of crock. ( Sounds like Australian slang!) e.g. valve is set 10" off d/c outlet from base of pump.Carl
I'll preface by stating that I'm not a plumber and if your talking about a sewage pump, then......never mind.
Is it possible that because of the distance between the check valve and the outlet, the the momentum of the water still moving in the pipe pulls the valve open until enough air has entered the pipe through the outlet to break the the siphoning action completely? It would be compounded by a long discharge pipe that has the outlet downhill from a high point at the house.
I think it could be stopped with a stand pipe Tee'd in the discharge line at the highest point to act as a siphon break. The height of the standpipe would need to be tall enough to prevent the "fountain effect" from the pressure in the pipe. Unless you want to have a little geyser in the yard.
I think you're probably right. From the check valve, located just below the 90 where it elbows towards the wall, stands 8' of pipe; then out the rim joist, then looped in the ground towards storm drain. Before check valve, the crock would almost fill again from what was charged back.thanks, Carl