That is funny
, Hylyte went exactly the opposite way of what I developed and I think for priming it will work equally well.
I have been trying out several systems and my latest one is just finished. From my seacock I have a hose to the strainer which is positioned on the waterline. The input and output connections are under the waterline but the lid is above (easy for cleaning). After that, I have a short hose to a PVC manifold under the waterline. I made that from schedule 40 PVC with a valve on every connections. I use the cheap
PVC valves that you glue on the pipes with PVC cement, so no threads. The first connection is the strainer; 2nd A/C and 3rd a deck
wash pump. The 4th one is the trick because it is plumbed to my pressurized fresh water system. This allows you to do many things, incl. priming the A/C circuit. I also use it for a fresh water deck
wash, or to flush the deck wash or A/C circuits with fresh water when they are not going to be used for a while. I can also backflush the sea strainer and seacock.
I will give it a year to evaluate if this is indeed the best I come up with but after all I did before coming to this setup, I'm pretty sure it's perfect.
Please note that this manifold is in my forward sail locker which is separated from the rest of the boat with a water tight bulkhead. If that wouldn't be the case, I would use marine
rated valves instead of the PVC valves.