12v/footpump system not working

[Clairebear]

So I’m attempting to install a new water system on my boat ((first timer if something looks funky please be nice)) I wanted a 12v system AND footpump system combo cause at times I feel like both would be useful. When I shut off the Manual side the 12v side works perfect, but when I open the footpump side the footpumps no longer work. What could be my issue here?

Water flow: the water runs from the tank under my bed to the 12v pump then to the water filter then down to the place under my sink. The hose then splits into a manifold I made. The first section off the manifold and as seen in pictures is the footpump hose. It comes off the manifold through an on/off valve ((I’d turn it off when electric is going cause the footpumps aren’t made to hold pressure, and then have it open when I wanted to use the footpumps)) then tees off, one side goes to the kitchen sink inlet and the outlet goes thru a one way valve ((so when 12v is on it doesn’t get forced into the pump)) and then to kitchen sink. The second off the t runs to head pump inlet. The head pump outlet runs to a one way valve and then T joins which carries one hose to manifold that will run to head sink and the other goes to shower. The other lines off the manifold are one to the kitchen sink from 12v and one to shower from 12v and end of manifold goes to head sink. At the inlet of kitchen sink, head sink, and head shower each have a T joint that accepts the hoses from both the footpump and the electric. So much to explain I know, but hopefully with words and the picture it makes sense.*

so basically everything’s hooked up and 12v runs find when footpumps are closed but when I wanna use the footpumps nothing will come out. Any ideas how to fix or solve or reengineer so it’ll work?

[Bowdrie]

Just as a beginning step, take that brass one-way valve, (check valve,) and orientate it in the proper position.
It should have the inlet/outlet ports in the horizontal position with that "dome" part upward.
They're just a brass "flapper" and depend upon gravity to work, (when they want to that is. ).
I would add that foot or hand pumps ALWAYS work better if they are not part of a pressure system.
Ideally, they should have their own plumbing from the tank that is separate from the pressure system.

[barnab]

Your 12v pump will not let any water flow through (unless it's pumping). You will need to connect the footpump suction side to a T between then tank and 12v pump.


I would remove the footpump sucktion hose from the T and stick it to a bucket to verify