Water maker pre-filters failed!

Yesterday I went to service the Kubota EA-300 generator / watermaker.  Was going to flush and re-pickle the membranes, change the engine oil, and fresh-water flush the seawater cooling system.

I did not get very far.

We did not need to use the Watermaker this summer, as shore-side water was readily available.  So the system just sat happy in the pickling juice. When I fired up the unit yesterday, I could not get any pre-boost pressure - the pre-filters were all clogged!  Upon inspection I noticed that the head assembly had bits of white plastic in them.  Further inspection showed where that all that came from.

Here is a photo of the head unit (above).  Notice the large On/Off handle on the top?  This shuttles a small white plastic assembly inside the head back and forth, you can see it (below).

However, take a look at a different head unit.  Notice anything missing?

Yup, here it is:

And you should see the other guy!
This one shows clear signs of being dissolved away.

All three heads had these shuttles damaged.  They really looked like they had been eaten-away, and in fact some of the plastic was still soft and pliable when I pulled the parts out.  I can only assume the pickling solution attacked this plastic.  Wow.   Not going to think about that one too much.  (or, maybe it was a band of Polymites that tried to attack Viking Star.  Finding no plastic to eat, they went for the Filter housings!  Polymites, the scourge of Tupperware boats everywhere!)

Today I picked up three replacement filter units.  The lower-cost ones without the fancy 'valving' at the top. Though these new units come with a solid blue plastic filter housing, the threads are the same and I can reuse the clear housing from the old heads.

Replacement - No Valve Handle

And no White Plastic to fail

Will reassemble the pre-filters, and add in the high pressure pump safety vacuum interlock switch I have been saving while I am at it.

But bottom line:  know that there is something that attacks those fancy filter heads.  Given the usage, there is really no need for the on/off valves - I just chose them because I liked the clear housing.  But if you are sourcing these, get the simpler ones.