Sump Pump Check Valve Woes

[Aaron Slepekis]

Hello All, I'm looking for some advice for a way forward.

When it rains a lot (over an inch) or there's a lot of snow melting (like right now), my sump pump runs a lot. For example, right now, I'm thinking it's pumping about 19 GPM out of my basement based on the manufacture's pump curve and the amount of time it's running. But here's where it's getting more annoying: last month the check valve has started chattering when the pump shuts off. Like "clunk-clunk-clunk-clunk-clunk-clunk-clunk-clunk-clunk-clunk-clunk" for several seconds.

The valve is a AY McDonald 4424-100 2069C "silent" model, I installed it new earlier this year because the previous check valve had started to water hammer. This one started to do that too... and now it's chattering. I have a thought that a weighted flapper may help? I like the idea of a weighted flapper over spring closing because I'm worried that a spring's life span would be too short given how much the pump runs.

Any help silencing the chatter would be appreciated.

 

[Mliu]

A properly designed spring should operate for over 10,000 cycles.

 

[Sponsor]

 

[Bert Lee]

How long and what size is the drain pipe? I had a similar situation but was a back flow sucking/gurgling issue that I was blaming on the check valve when in reality it was the water that remained in the too small and too long drain pipe that was not sufficiently vented and it was the suction of the exiting water trying to find balance in leaving the long pipe that was literally sucking the check valve open. The water in the pipe continued in both directions until some air balance was found within the pipe. Every time. I added a couple small AAV vents into the system and it has corrected that 95%.

 

[Aaron Slepekis]

Thanks for the input.

@mliu, it's good to know that a good check valve will last that long. I'm a little worried how quickly it will get to 10,000 cycles, because there can be times when the pump is running for 15 seconds or more ever 4 seconds. A couple times the pump ran for 24 hours a day for a couple days.

@burt lee, the pipe is 1-1/2", and about 14' straight horizontal from the pit to the outside wall and another 20' or so to pipe it away from the house. I had wondered if it might be negative pressure issue. Covering the discharge with my hand after the pump cycles, I can feel the vacuum being pulled. I might try adding AAV's. But another thing to add that I discovered today: if I cover the weep hole, it has an effect on the chatter.

 

[Bert Lee]

Thanks for the input.

@mliu, it's good to know that a good check valve will last that long. I'm a little worried how quickly it will get to 10,000 cycles, because there can be times when the pump is running for 15 seconds or more ever 4 seconds. A couple times the pump ran for 24 hours a day for a couple days.

@burt lee, the pipe is 1-1/2", and about 14' straight horizontal from the pit to the outside wall and another 20' or so to pipe it away from the house. I had wondered if it might be negative pressure issue. Covering the discharge with my hand after the pump cycles, I can feel the vacuum being pulled. I might try adding AAV's. But another thing to add that I discovered today: if I cover the weep hole, it has an effect on the chatter.

The weep hole matters but honestly, with that length of run and a 1.5" capacity it sounds nearly identical to my issue. The weight of that outgoing water is literally pulling that check valve open as it's starved for air. I added two AAV to my system as mine is a longer run and really poorly designed. But the idea is the same. You can hear the working every cycle. And because I used some threaded connectors they're easily removed and capped or replaced in seconds.