Curious about Lectra/San electrode pack

R

robedney

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exMember
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Oct 19, 2004
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15560
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This is purely curiosity on my part. My electrode pack was not working properly so I pulled the unit and took it apart, removing the pack. It looks as if the two terminals perhaps reverse polarity on every other plate, but my meter showed high resistance everywhere and I couldn't sort that out. Using a Dremel and a router bit I dug into the plastic out of curiosity. It appears that the copper connections have corroded (inside the solid plastic casing), although the plate material looks fine.

Also, out of curiosity, what are those plates made of? Is it stainless or something more exotic?

Also -- for Vic -- what sort of life might I expect out of the new pack? Is it normal for them to have interior corrosion like this?
 
OK Rob, here we go. With the electrode pack removed from the unit, clean and dry, there should be no continuity between any of the 3 plates. There should be continuity between the bottom plate and the outer brass stud, and continuity between the top plate and the inner brass stud. That's all. The center plate should not have continuity to either stud - it should show up as "dead" on the ohmmeter. Anything other than that indicates a short circuit somewhere.

It sounds like you've had salt water intrusion through the black sealant, and that the electrode pack isn't functional any longer. This is not a normal situation, and is extremely unusual. Perhaps the black sealant didn't adhere properly to the plastic body of the pack...?

The base metal of the plates is titanium, and it is plated on one side with a microthin coating of a very expensive proprietary rare earth compound. The coating on the plates multiplies their ability to conduct electricity. Titanium by itself, is very resistant to electrolytic corrosion but it isn't a particularly good conductor of electricity. So the coating solves that problem. However, with use, the coating gradually erodes away, and it eventually reaches a point where the plates won't conduct electricity sufficiently to do their job. Even though they may appear to the eye, to be perfect, they simply no longer work. At that point, replacement is the only option - they cannot be re-plated or rejuvenated.

Normal electrode pack life is 3-5 years if you are a weekend boater; less if you are a liveaboard.

Operating the unit under low salt conditions will accelerate the rate at which the coating erodes away, so any time the unit is complaining about low salt, don't ignore it. Get the situation corrected as soon as possible, a replacement electrode pack is relatively expensive.
 
Once again, thanks very much for being on this forum Vic. I love knowing how things work, and you've answered all my questions. Also, I didn't realize that the electrode pack is really a maintenance item -- but it makes sense to me now. Also the price of the pack makes a lot more sense. I am a liveaboard on a 60' steel trawler that I've been converting. I had one kid living with me still in college -- but now have two more because grads can't find jobs! Our LectraSan is obviously an important part of our lives! Well, maybe I should say an important part of my life -- these are three girls and unless I repeatedly point it out they tend to assume that human waste just sort of magically disappears post-flush. Between the three of them and their friends I have a heck of a time keeping tampons and sanitary napkins out of the Crown head. I finally put up a sign that demands a minimum charge of $70 if I have to service the head because they "accidentally" flush one of those nasty things. Trouble is they can get right through the head and wrap their nasty fibrous tentacles around the macerator and the mixer in the LectrSan too. Of course, none of these kids have $70, so it's more of a symbolic kind of thing :)
 
Robert, LOL; I know exactly what you mean, and you are 100% correct, re: the tampons and pads.

Here in the Northeast, many marine plumbers charge a flat rate of $200.00 to unclog a marine toilet that has the notorious "white mouse" caught in it. I can sympathize with you, having three daughters living aboard.

I've been fortunate; I have 3 sons. I did have to explain to them however, that condoms will also foul up a marine toilet...
 
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