You didn''t say if the pressure was weak at every faucet on the boat or not. If it is one faucet, look for a kinked line
or something crushing the line
or a trapped air bubble at the top of a loop. Is it hot and cold side? Accumalator tank could be problem, but I would think that would cause the pump
to cycle often and the pressure to fluxuate accordingly. If the pump
isn''t running and you have low pressure at the outlet, I would bet on a kink. One other test you can do is to turn the faucet off and wait for the pump
to quit running then turn it back on. If you get a burst of pressure and then weak flow, look for the blockage in the line
. I have had to take a spare valve assembly and break into the water system up-stream of the faucet and try it there. Then it is just a matter of isolating the section of piping/hose to see where you are loosing in. Try as close to the pump
as possible first to eliminate the pump as the problem. Good luck.