Watermaker -- Where Would You Put It?

[rom]

Originally Posted by poiu

The manual says it is OK. I checked that before I posted. The membranes work fine and are so after many years of use. I normally make water every 2 to 3 days. Having shorter periods makes more sense.
Prefilters look fine after 4 days. Slime in there is not visibly growing fast enough to see.

I'm wondering why Tellie is so firm on his advice, if I have I been very lucky and my watermaker manufacturer foolish to give their conflicting advice?

Same experience here.

I will say it again as it was not understood the first time: my manual says that if I fresh water flush, then I HAVE to salt water flush before using the watermaker again. Fresh water under pressure in the membrane in enemy #1 per Dessalator manual.

And if this is true, then experts here should not forget to remind us about that. As some may actually kill their membranes by following the fresh water flush advice and not this one ...

[Dockhead]

I'm very grateful to everyone for all the excellent advice and interesting conversation.

After a lot of thought, I think I've decided to do it quite differently after all -- just buy a portable watermaker which does not need to be installed. The Nautilus guys make a portable version of the one I was looking at.

I know these are a big pain to use compared to fixed installed ones, but I will be using it over a fairly limited period of time, and when I get back from Greenland I can sell it, or pickle it and keep it for the next boat. Otherwise, I will go through the immense hassle of installing it, and then I'll lose it when I sell the boat -- it will just be a gift to the person who buys my boat -- I'm quite sure the cost of it won't be reflected in the price I get for my boat.

[Pete7]

That is a sensible compromise, after all you may not need to use it. Just send the crew off to the nearest glacier with a couple of buckets. The price of blue glacier ice for a cocktail at the top of the tower in Calgary was breath taking

[Catalysis]

We carry a couple of 24v Spectra 340z so have 100% on-line spares located in a passageway locker for easy access.

[250224]

Originally Posted by rom

1As some may actually kill their membranes by following the fresh water flush advice and not this one ...

The Katadyn manual doesn't mention freshwater. It says that if you re-use the watermaker within ~3 days you can simply switch it of. It also depends on temperature, when it is warm, earlier, else up to a week. For longer breaks one should use a preservative to prevent organic growth on the membrane. Here freshwater is preferable but clean seawater is well also.

I don't see a principled problem with sharing the engine water intake with watermaker. In fact this is the installation on my boat (but admittedly the watermaker is/was not often in service). This said, it is interesting to read other opinions and think about if one could be affected.

[Lodesman]

Originally Posted by rom

And if this is true, then experts here should not forget to remind us about that. As some may actually kill their membranes by following the fresh water flush advice and not this one ...

I think the key part is "fresh water under pressure". My instructions say something similar:

10. While performing a system freshwater rinse, be sure that the pressure regulating valve is in the completely open position, which can be verified by turning the pressure regulating valve counterclockwise until it physically stops. Running fresh water or brackish water at elevated pressures through the RO membranes will permanently destroy the membrane.

[Lodesman]

Want to add for the OP, this warning:

4. In brackish water, such as in an estuary or river, never allow the product water production flow rate to exceed the units rated output. In such cases, simply turn down the system pressure or RO membrane damage will occur.

When sailing Greenland, you might be wary of glacial freshets in the inlets, if and when you make water.

[Dockhead]

Originally Posted by Lodesman

Want to add for the OP, this warning:

When sailing Greenland, you might be wary of glacial freshets in the inlets, if and when you make water.

Thanks; hot tip.

[Tellie]

OK guys. Thanks Lodesman for posting the above instructions that came with this watermaker. The instructions are quite clear to me but I can certainly see how this can be confusing (pardon the snobbish sound). The instructions do not mean that fresh water itself will damage the membrane, what it is trying to say is that high pressure will certainly damage a membrane. What they are trying to prevent is a system that has it's needle valve set for pressures to begin the RO process in full on sea water. That's why they are telling you to open the valve all the way. Salinity of the water makes the difference in internal pressures and flow. The fresher the water the lower the pressures needs to be to produce product water. A standard plunger pump can easily exceed the 1000psi rating of a standard membrane. As the water gets fresher the other effect of a pre-set pump is the flow will increase. Membranes are designed for a set maximum flow as well, exceed this flow rating and pressure and you will certainly damage the membrane. Both of these effects would be the same with fresh water or salt. So this has nothing to do with it being fresh water. Also, water temperature can make a huge difference in the frequency needed for fresh water flushing. Run your watermaker in cold water and you could get away with longer flush intervals. But come further south, especially in the tropics, and the weekly flush may become an every three day flush or you will certainly be referred to my rule #2. One more way to look at it. I know many of you have or have had salt water flush heads. Remember what happens if after three days or so when you haven't used it? This is EXACTLY what happens inside a watermaker that has not been fresh water flushed. Again, ALL watermakers need to be fresh water flushed after each use and about once a week if not in use. If fresh water were a killer of membranes why would we use it with pickling agents? Every major watermaker company in the world adds a charcoal filter to their systems for fresh water flushing for very good reason. Why any company that wants to be in the watermaker business doesn't automatically add a fresh water flushing system or charges it as an extra add on to their units is almost reprehensible.

J.T. (aka Tellie)
HaldenMarineService@yahoo.com
(954) 515-7077
Spectra watermakers
BlueWater watermakers
RainMan watermakers

[Tellie]

Originally Posted by weavis

Hi Tellie.

It is true a lot of us have our own experience and understanding re boat things. However, I want to thank you for your considerable experience given freely, and the couple of things I altered due to your suggestions have worked well in the past.

This is the strength of CF.

I appreciate it.

Thanks Weavis, I really appreciate it and all that CF and it's moderators do. But it is truly I who benefits the most from CF.

[donradcliffe]

Mine was a 12v under a guest berth forward, sharing the thru-hull and power with the washdown pump.

One delivery on a boat with a well known AC watermaker in the engine room, the high pressure pump had some pin holes develop mid Atlantic. The engine room was foggy with saltwater mist, which took out the Genset, Inverter, and Bow Thruster. I also had to have the crew flush the freshwater toilets with 5 gallon buckets of seawater for the remainder of the crossing.

[Dockhead]

Originally Posted by donradcliffe

. . . One delivery on a boat with a well known AC watermaker in the engine room, the high pressure pump had some pin holes develop mid Atlantic. The engine room was foggy with saltwater mist, which took out the Genset, Inverter, and Bow Thruster. I also had to have the crew flush the freshwater toilets with 5 gallon buckets of seawater for the remainder of the crossing.

Yikes!

[Jon Hacking]

Originally Posted by Tellie

OK guys. Thanks Lodesman for posting the above instructions that came with this watermaker. The instructions are quite clear to me but I can certainly see how this can be confusing (pardon the snobbish sound). The instructions do not mean that fresh water itself will damage the membrane, what it is trying to say is that high pressure will certainly damage a membrane. What they are trying to prevent is a system that has it's needle valve set for pressures to begin the RO process in full on sea water. That's why they are telling you to open the valve all the way. Salinity of the water makes the difference in internal pressures and flow. The fresher the water the lower the pressures needs to be to produce product water. A standard plunger pump can easily exceed the 1000psi rating of a standard membrane. As the water gets fresher the other effect of a pre-set pump is the flow will increase. Membranes are designed for a set maximum flow as well, exceed this flow rating and pressure and you will certainly damage the membrane. Both of these effects would be the same with fresh water or salt. So this has nothing to do with it being fresh water. Also, water temperature can make a huge difference in the frequency needed for fresh water flushing. Run your watermaker in cold water and you could get away with longer flush intervals. But come further south, especially in the tropics, and the weekly flush may become an every three day flush or you will certainly be referred to my rule #2. One more way to look at it. I know many of you have or have had salt water flush heads. Remember what happens if after three days or so when you haven't used it? This is EXACTLY what happens inside a watermaker that has not been fresh water flushed. Again, ALL watermakers need to be fresh water flushed after each use and about once a week if not in use. If fresh water were a killer of membranes why would we use it with pickling agents? Every major watermaker company in the world adds a charcoal filter to their systems for fresh water flushing for very good reason. Why any company that wants to be in the watermaker business doesn't automatically add a fresh water flushing system or charges it as an extra add on to their units is almost reprehensible.

J.T. (aka Tellie)
HaldenMarineService@yahoo.com
(954) 515-7077
Spectra watermakers
BlueWater watermakers
RainMan watermakers

Tellie, thanks for this & for your earlier posts. It's apparent that you know your watermakers, & the rest of us on CF appreciate you sharing that knowledge.

What I'm hearing is that with direct drive CAT pumps, the pressures can go too high with fresh water, & that's the real reason some manufacturers are saying to reduce pressure when flushing. It's not that fresh water, per se, will damage the membrane, it's the higher pressures.

We've had a Spectra (380) for 16 years, & it seems to reduce the pressure on its own when we flush. That's how we know the fresh water has made it to the membrane - when the pressure goes down.

In fact, we'll sometimes take (fresh) deck water that's not quite drinkable & run that through the Spectra, to make it drinkable. There's nothing I can find in the manual about this, but it seems to work (& uses less power than processing salt water). Is this OK? TIA!

[Fuss]

Originally Posted by poiu

The manual says it is OK. I checked that before I posted. The membranes work fine and are so after many years of use. I normally make water every 2 to 3 days. Having shorter periods makes more sense.
Prefilters look fine after 4 days. Slime in there is not visibly growing fast enough to see.

I'm wondering why Tellie is so firm on his advice, if I have I been very lucky and my watermaker manufacturer foolish to give their conflicting advice?

Strange that you never had a problem with 4 days without freshwater flushing.
I have experience running 3 watermakers 24x7 with one given a bit of a rest sometimes.
A few times, when the freshwater flush was not done then after 2 days the prefilter water went black and smelled terrible. I don't know why the reaction was so bad, but we don't take chances and the freshwater flush is done regularly.

[rom]

Originally Posted by Fuss

Strange that you never had a problem with 4 days without freshwater flushing.
I have experience running 3 watermakers 24x7 with one given a bit of a rest sometimes.
A few times, when the freshwater flush was not done then after 2 days the prefilter water went black and smelled terrible. I don't know why the reaction was so bad, but we don't take chances and the freshwater flush is done regularly.

I just checked my logs, changed the 5u prefilter after 130h, was real dirty but only a light smell. I use my WM in the same way poiu does.
I guess the difference with your experience comes from where you use your WM ?