Is there any downside to having two check valves in series? I'm installing a new sump pump that came with a new check valve. Several feet from the sump pump, there is an existing check valve on the discharge pipe.
Unless there's a reason not to, my plan is to install the new check valve lower on the discharge pipe leaving the existing check valve on the same discharge pipe.
Best Answer
With the two in series you will be protected against one valve being stuck open. I don't think it's necessary and I wouldn't install two in series but since one is already there, no sense in having to change the plumbing by removing the old one.