I found that valve seats on my watermaker pump are pitted. I emailed the photos to DESSALATOR. They told me that the pitting is due to electrolysis on my boat.
Yesterday I tried to investigate that. I found that bonding system is connected with negative contacts of 24V.
Based on our forum discussions, it is not right.
Engine frame, engine, and alternator on the engine are also connected to bonding. My boat is on hard now.
SM #345 "LIFE IS GOOD"