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Water maker Questions


Craig Briggs
 

Not sure what your "green zone" translates to in bars as I have a gauge with numbers and 60 bars +/- is where these operate (actually I usually get good tds at 850 psi / 58 bars). These pumps typically deliver up to 69 bars / 1000 psi, which would be a fine pressure at which to test.
--
Craig - SN68 Sangaris, Tropic Isle Harbor, FL


Porter McRoberts
 

Great intel. Thank you all!
Testing today. 
Porter 

Porter McRoberts 
S/V IBIS A54-152
WhatsApp:+1 754 265 2206
Www.fouribis.net

On Sep 4, 2020, at 2:00 AM, Craig Briggs via groups.io <sangaris@...> wrote:

Not sure what your "green zone" translates to in bars as I have a gauge with numbers and 60 bars +/- is where these operate (actually I usually get good tds at 850 psi / 58 bars). These pumps typically deliver up to 69 bars / 1000 psi, which would be a fine pressure at which to test.
--
Craig - SN68 Sangaris, Tropic Isle Harbor, FL


Mark Barter
 

This is a really useful thread. 


Nunky is fitted with a Dessalator D100. We assumed that the green light meant it was working well. When it became apparent that it wasn’t we had a tank full of brine. I now know that the green light means nothing. I actually tested the output against sea water and somehow it was worse.

I have no idea when the water maker was last used but my guess is months and months before we bought the boat. Due to various issues including Covid we were then away from the boat for months. I didn’t know about pickling and regular flushing at that stage so it’s hardly surprising that the water maker isn’t working properly.

I am going to clean the membranes to see if that helps but if it doesn’t it’s either 3 new membranes at £500 each or a new system with proper quality control. 

Has anybody managed to successfully resurrect a system from this state? If so, how?


--
Mark & Nicky Barter
S/V Nunky
SM 110


 

I suggest that you need to back up some from your assumptions and take a different approach. First of all, if you pay £500, for SW302521 Filmtec membranes, you are definitely overpaying. They should be about $200USD plus VAT/Freight. There is one membrane manufacturer in the world, so it makes no difference where you buy membranes.

Allow me to make a few points:
  • Your Dessalator watermaker is probably 17 years old if it is as old as the SM. Most other brands do not last that long. Dessalator is a modular design which means modules can be replaced or overhauled.
  • There can be other causes for a water maker not working. Membrane tube seals could be one of them. 
  • If there is a membrane failure, it may be only one of them.
  • When a watermaker has been neglected and not used, you should allow it to run for at least 30 minutes, discarding all product water before testing.
  • Membranes require moisture. If a membrane is allowed to dry, it will probably never work again.
  • Some water maker manufacturers promise a lot and deliver very little. Dessalator is not one of these manufacturers.
I suggest that once you put the Dessalator water maker in good working condition that you religiously do the following:
  1. Rinse the membranes weekly following the instruction, or run the watermaker every 3 days.
  2. If you do not have a method of discarding produced water from the watermaker, add a 3-way valve to do this.
  3. Before you add any water to the tank, test it. You will find that the TDS will decrease as the watermaker run increases, usually allowing 300TDS or less after 5 minutes.
I hope this helps you.

CW Bill Rouse Amel Owners Yacht School
Address: 720 Winnie, Galveston Island, Texas 77550 
View My Training Calendar


On Sat, Sep 5, 2020 at 1:31 AM Mark Barter <markbarter100@...> wrote:

This is a really useful thread. 


Nunky is fitted with a Dessalator D100. We assumed that the green light meant it was working well. When it became apparent that it wasn’t we had a tank full of brine. I now know that the green light means nothing. I actually tested the output against sea water and somehow it was worse.

I have no idea when the water maker was last used but my guess is months and months before we bought the boat. Due to various issues including Covid we were then away from the boat for months. I didn’t know about pickling and regular flushing at that stage so it’s hardly surprising that the water maker isn’t working properly.

I am going to clean the membranes to see if that helps but if it doesn’t it’s either 3 new membranes at £500 each or a new system with proper quality control. 

Has anybody managed to successfully resurrect a system from this state? If so, how?


--
Mark & Nicky Barter
S/V Nunky
SM 110


John Clark
 

Hi Mark,
  As Bill says the Dessalator is a good design.   There are parts available and support form Amel and the Amel Owners Group, I would suggest sticking with it and doing a ground up rebuild

When I bought Annie (SM37) the previous owners had not used the watermaker in over eight years so it was a known project. I suspect your watermaker may be in a similar state.  The good news is that it is fixable with a little bit of time and patience.  I recovered my watermaker replacing the membranes, the membrane endcaps (precautionary as they were original and had stress cracks) and the high pressure hoses(also a precaution).  The pump needed to be disassembled and cleaned before it would build pressure but it was pretty easy to do.  Once back together she ran fine.  It sounds like your pump is functioning so you are probably good there.

The worst issue with the Dessalator was the early control system which as you found out does not actually test the water quality.  I deleted that whole bit of junk and test the water myself before sending it to the tank. I currently have the product water discharging to a free hose that I allow to flow into the cockpit when the unit runs.  I sample with a portable TDS tester then put the hose into the fill nozzle when it is good quality. Nothing goes into the tank without monitoring. I think Bill suggests doing that somewhere below.  That is the best way to ensure your getting good water. And that can be very important if you are underway relying on your tank for potable water.   One bad batch from the WM and poof you have no water at all.

To get SW into your tank you either have a bad o-ring or the membranes have been damaged.  Ether way replace the membranes and o-rings and you are good, and will know for sure the condition of the membranes.

Thoughts:
I installed my membranes in 2017, they are still running just fine.  Run the WM every once in a while for a few hours, never pickled it.   If the boat will be idle, I flush them with fresh water.
Check the end caps on your membrane vessels for signs of cracking.  I think Dessalator has new material available now that won't become brittle.
When you reassemble, watch your hoses when the unit is running, make sure they are not rubbing on anything.
Verify the pressure gauge is reading correctly.  My gauge is not the red/green version but read in Bar.  It is reading 15Bar higher than actual.
Change pressure slowly.  Both up and down.
Run the unit with no pressure to flush the concentrated brine out of the system after you are finished making water.
 I bought a solenoid valve to be able to test the water at the galley sample port and then flip a switch to sent it to the tank.  That is a better solution, but I have been lazy.  
Portable TDS /conductivity testers are cheap and available online.  

Regards,  John Clark
SV Annie SM 37
St Thomas USVI

  






A couple of suggestions