Haven’t had a similar problem on my watermaker
, but have decades of experience with moderate pressure (3000 psi) hydraulic systems.
Several possibilities occur to me:
1) you state that there are no obvious leaks
. Maybe your membrane failed, and the “leak” is to the freshwater output. If this were the case, you would have greatly increased output, maybe even blowing the usually low pressure hoses and fittings, and of course the output would be salty.
2) even with new pre-filters, your feed water
sub-system might be clogged. Do you have a low pressure feed pump
? Is thruhull open, and not clogged? Easy check - remove low pressure feed line from high pressure pump, turn on system, lo pressure feed pump, and see if you have copious salt water
flow out the end of the low pressure line. Don’t run it too long, the high pressure pump won’t like being run dry.
3) If neither of these checks shows any problem, the high pressure relief valve may be stuck partially open. I’m guessing this is your ”pressure regulating tbar”. You might dismantle this, check for debris, failed o-rings, broken springs, lack of movement in internal mechanism. Make sure you mark lines before dismantling so you put the assembly back together correctly
4) Go see Rich at Cruiser’s Supply La Paz