Bobs, the pressure vessel of a watermaker
is out in the open with 800 psi inside, and the most common HP pumps can put out 2-3000 psi if the discharge is closed. Cpt Dan, buy your pressure vessel and membrane as an assembly. Unless you work for minimum wage, you'll save money
. In fact, I would recommend you buy the complete system in a fully modular configuration - that's all the discrete components and you mount, plumb and wire them yourself.
When installing a watermaker you want to run the product output line all the way to the top of the water
tank. If you must tap it into the existing water supply line, as is frequently done, you MUST install both a spring-loaded ball or cone check valve AND a carbon filter in the line. Otherwise, chlorine from dock
water in the tank will migrate through the water path and kill the membrane over time. You should include in your installation
3-way valves in the seawater suction and brine discharge lines for cleaning
and preserving, and another in the suction for flushing
the unit with fresh water AFTER EACH USE (not necessary with DAILY use). The flush line must have a carbon filter to remove chlorine, and that filter element must be replaced when about 200 gallons of dock
water has run through it - about 30 flushes more or less. The used elements can be rejuvenated by placing in a warm oven
for a while, or simply airing out.
Yes, I sell them. It's not the purpose of this reply, but if you need a source, email
me at: firstname.lastname@example.org