Village Marine Little Wonder water maker.

[Davidhoy]

Originally Posted by Nightsky

Let me start off by saying that I am NOT familiar with this particular brand and model of watermaker, so if there is a functionality peculiar to this type, my comments may not apply. However, I have had RO watermakers (3 different ones) on my previous boat for 21 years. The first was a 12v unit that had a small, half height prefilter that needed replacement after each use and were difficult to source. I eventually replaced that with a used SeaRecovery 600 gal/day IIRC that I kept for several years but decided to replace when the electronics and auto functions crapped out. I replaced it with a ProWatermaker, 500 gal/day, single membrane, totally manual unit which performed very well. A couple of comments you made in one of your replies to someone may be inaccurate. You state you were told that removing one of the membranes would only result in a 0.5 gal/hr reduction. My understanding is that you can stack multiple membranes to double or triple output (provided you have a pressure pump and motor that can handle the extra load. So, removing one membrane, in your case would result in half your current output. Also, the only time there would really be double the maintenance cost would be if you replace 2 membranes instead of one. Normal membrane cleaning, pickling, etc won't require any more material than it would to do one membrane. If half the output suits your needs, then you can save $ in replacing the 2nd membrane.
There is one other cause of the foul smell. Sea water contains plankton in it. Even deep sea, dark blue ocean water. The pre-filters get most of this before the water makes it to the membrane. After each use I would pull the filters (20 micron and 5 micron) and wash them thoroughly in fresh water, put them back in the filter canisters and fill them with fresh water. I would also use some fresh water from the tank, run through a carbon filter and flush out the membrane. If I didn't wash with fresh water, and I didn't use the RO machine for a week or more, then the plankton in the sea water surrounding the filters and membrane would start to rot and smell and turn the filters black.

It was the guy at the Parker-VM store in Fort Lauderdale that told me that the second 23" pressure vessel and membrane only add about 0.5 gal/hr in throughput, and he showed me the number to back his statement so I'm inclined to believe him. He could easily have tried to sell me two new membranes, instead he suggested only going with one. I'm willing to take his word on this one, as he knows the product far better than I do. If I can get a good deal on a 40" pressure vessel to replace the two 23" ones I currently have, that might be worth considering...

As to the smell, it was when I removed the hoses to the pressure vessels that I noticed it, indicating biological contamination and decay on the membrane(s) itself - not a good sign :-(. And since I have no idea how long the system has been sitting unused (several years at a minimum), I'm not willing to risk the health of my crew and me on potentially contaminated water. A fresh membrane is a small price to pay to ensure everyone's safety.

Regards,
David

[44'cruisingcat]

$1000 to replace a membrane, re-power and service the pump sounds like a very fair price.


It's a very good watermaker, will give years of service, and makes good litres per amp hour. Good luck with it!