I installed a zoeller 508 backup sump pump. It has a small check valve that is installed directly into primary pump. Ny original setup without backup has standard check valve a few feet above pump and a hole drilled between the two as per Zoeller.

I left the original ckeck and drilled hole in place.... so there are two check valves now and thinking about it now im concerned i shouldnt have done that.


Is this an issue?.

the check valve in the secondary pump is so the primary doesn't pump water back into the pit thru the tee the secondary is connected to.

Actually there were 3 check valves in my setup.... 1 supplied by zoeller for the outlet of the primary. Another integrated into the backup pump and a third which i had upstream in my sump drain as my primary when i had a single pump.

There were 3 weepholes also... one in the housing of my primary pump, another in the zoeller supplied check valve above the threads and a third which i had drilled a 3/16 hole between pump and my check valve like i had it for a single setup.


Im not sure if it would cause airlock issues or make the pump work harde because it seemed to be pumping correctly. However, there was a "gurgle" noise coming from the drilled weep hole after it pumped.


So I cut out the section of pipe where i originally drilled the weep hole for a single setup and i removed the upstream check valve and replaced it with a fernco coupling. No more gurgle noise after a cycle.


Too bad the manual doesnt address the chance there is a check valve upstream. And i have to rely on a little cheapo zoeller check valve rather than the quality large ones i usually use.



Edited 2 times.

this is how the few I have installed are piped.
also, this is how liberty pumps recommends they be piped.
you can always remove the check you don't like and put one you do like up higher.
fine to do as long as the secondary pump tie in is above the new check valve location.
do drill a hole below the primary pump check.
TIP.. drill the hole at a 45 deg angle facing down. the pumping water exiting that hole will shoot downward not sideways.

What about the redundant check valve... that was bad right?

However, I think I recall that there are multiple check valves in a well pump setup.

I'm not an engineer in fluid dynamics. but I don't believe the extra check valve would cause a problem.