Your problem is not from a check valve, but from air that is entrained under the boat filling the seachest.
Like every design decision on a boat, the seachest has its good points--and its problems. One of the issues is that when sailing, it fills with air. If you have ever put a video camera under your boat when sailing, you've seen a steady stream of bubbles flowing from bow to stern even at relatively modest speeds. Every one of those bubbles that manages to go under the main intake thru-hull rises up and displaces water from the seachest. After a fairly short time, the seachest is full of air.
This means that any pump drawing out of the seachest, needs to clear a fairly significant volume of air before it can pump water. I suspect this dry run time on every startup underway is part of the reason so many people have had such troublesomely short lifespans from impellers on their gensets.
Of course, this happens with every thru-hull, no matter if there is a seachest or not. The issue with the seachest is that it can hold a LOT more air than a simple hose connection.
The previous owner of Harmonie installed a very small pump plumbed from the seachest manifold to to the cockpit scupper that can be used to clear this air before running either of the engines.
I think with the toilet flush pump, you'll just have to live with the delay, unless somebody has a solution I haven't thought of yet!
---In amelyachtowners@..., <karkauai@...> wrote :
I have a different probem with my aft head on Kristy. When at sea, the fill pump takes forever to start putting water into the bowl. This is not a problem when at anchor, and it doesn't matter which tack I'm on when at sea. There is a strainer with very fine mesh in the intake line that looks like an orange mushroom. The stainless mesh is damaged and needs to be replaced, but it's acting like there is a one-way valve in the intake line that has failed. Is there such a valve? if so, where? Any other ideas?
Does anyone know the manufacturer of the "orange mushroom" strainer in the intake line? A source for the stainless strainer mesh?
I should say that on Kristy, (SM 243) there are separate thru-hulls for the seawater fill pumps located in the little "hallway" just inboard of the heads. She does NOT have the long hoses from the sea chest/manifold in the engine room.
Thanks for any suggestions.
Currently St. Michaels, MD, USA for the hurricane season.