Ballast issues -- check valves?

I installed a Jabsco Ballast Puppy and Fly High Integrated bow sack over the winter. I used rubber-flapper check valves to push water out the side when draining.

The system worked fine the 3-4 times we first used it. When trying to fill the bag this weekend, the Jabsco was sucking nothing but air. I think my drain check valves aren't closing all the way when filling, causing air to get into the system while filling. There are no leaks in the hoses or fittings.

After searching on here, it sounds like "swing check valves" are the way to go... just need somebody to confirm that check valves are likely my issue. Or if there is something else I should look at?

Thanks for your help in advance!

Assuming you are filling and draining through the same thru-hull fitting, you do not need a check valve installed when using an impeller pump (like your Jabsco). That style of pump will not allow water to flow through its manifold when it's not running, so it in turn acts as a check valve.

I would start by removing them from your system so you simplify everything. That will make tracking down the culprit easier.

Jason
www.wakemakers.com