This is a water, gallon meter, you set it for about 100 gallons and if a hose or pipe breaks inside, it shuts off. Therefore, the most you can flood your boat is about a 100 gallons which wont sink it!
These are all labeled now.
Left to right.
Heat Pump, Port Engine, Stbd. Engine, Generator.
Underneath. These go to the top of the sight glass strainer that I welded a 3/4" hose fitting onto the top of it.
To flush the system, one at a time, open the corresponding red valve while the engine is running, flush out for a minute or two. You keep the seacock open so any excess pressure will not flood anything and will go back out the intake scupper. City pressure is greater that the pump suction.
Shut engine off, and quickly close valve.
That's it!
Only one hose connection when you get back into port.
No hatches to open, or other hoses to connect or disconnect.
Some of the connections before you install it in the boat.
Just a few pictures.