Sump Check valve question

[Jack]

Hello, Is a check valve necessary for a sump pump installation? . I have about 8 ft - 1 1/2" pvc pump coming up out of the pit to a 90 degree elbow which is then exiting the house. There is an 1/8" bleed hole at the fitting near the pump. The pump is a high-output model than is in place just for extreme emergencies. The pit has some small holes in the bottom to assist drainage. . It seems like the check valve would hinder water flow. Therefore, is a check valve necessary? Thank you for your time.

[Joseph Meehan]

Use the check valve. It will make the whole thing more efficient and the pump will run less. It will not hinder the flow.

[Mark]

it depends on how the float switch is set.

without a CV, when the pump pumps, and the water in the sump lowers and the pump stops, the water left in the pipe will drain back into the sump... if it is a significant amount of water the pump will start agin soon and repeat the cycle so you waste a lot of pumping the water up and down the pipe..

if you can set the float switch for lots of hysteresis so the pump runs long enough so the water in the pipe is a small fraction of the amount pumped then its not a problem..

in fact I don't like a check value because after the rain stops, the water left in the pipe just sits there forever and can freeze or cause mold etc..

generally water left in the sump will seep into the ground but water trapped in the pipe by the CV will stay there a long time..

I also like to put a small air relief hole near the highest point in the pipe so that when the pump shuts off, the water drains back down and also forward.

Mark

[Joseph Meehan]

Very true, I had simplified the situation.