Got a free watermaker array. Now to finish it out.

[MV Wanderlust]

As luck would have it, I ended up with a brand new 2.5 x 40" membrane. On the same day, a mechanic friend of mine gave me the pressure vessel array from a Sea RO watermaker system.

He gave me this:


It's from this NS500 system:


I'm thinking of giving it to my buddy, who just bought a boat and wants to install a watermaker. To make this useable, he would need:

* A low pressure feed pump
* A stainless steel high pressure pump
* A set of filters with a gauge
* Various hoses, fittings, wiring, fuses, and switches
* A charcoal filter and manual valve for freshwater flushing

Anything else?

Any recommendations on the parts noted above would be greatly appreciated.

Thanks.

John

[Privleoplag]

Some one-way flow check valves

[redneckrob]

Originally Posted by MV Wanderlust

As luck would have it, I ended up with a brand new 2.5 x 40" membrane. On the same day, a mechanic friend of mine gave me the pressure vessel array from a Sea RO watermaker system.

He gave me this:


It's from this NS500 system:


I'm thinking of giving it to my buddy, who just bought a boat and wants to install a watermaker. To make this useable, he would need:

* A low pressure feed pump
* A stainless steel high pressure pump
* A set of filters with a gauge
* Various hoses, fittings, wiring, fuses, and switches
* A charcoal filter and manual valve for freshwater flushing

Anything else?

Any recommendations on the parts noted above would be greatly appreciated.

Thanks.

John

I'm actually engaged in a similar project as we speak. One thing to add to your list is some kind of salinity detector with a relay connection that powers a 3 way diverter valve. This ensure that the product is dumped overboard until the salinity is below the limit you set. You want this to be automated even if nothing else is, because potentially you could spoil your entire freshwater tank if it starts putting out high salinity product and dumping it in your tank. I have yet to be able to source a 3 way valve at 12 volts, so will probably end up with two 2-way valves, one normally open and one normally closed.

[MV Wanderlust]

Originally Posted by redneckrob

I'm actually engaged in a similar project as we speak. One thing to add to your list is some kind of salinity detector with a relay connection that powers a 3 way diverter valve. This ensure that the product is dumped overboard until the salinity is below the limit you set. You want this to be automated even if nothing else is, because potentially you could spoil your entire freshwater tank if it starts putting out high salinity product and dumping it in your tank. I have yet to be able to source a 3 way valve at 12 volts, so will probably end up with two 2-way valves, one normally open and one normally closed.

Interesting. Please keep me informed about what you find. It’s probably something he will want to add.

[Cpt Mark]

Here is an inexpensive watermaker option. You could DIY or in your case, figure out what all the bits are you need to build from what you have.

https://seawaterpro.com/

I am not affiliated with them in any way. Looked at them and talked with them about buying their unit and then found an old used watermaker for $300 and went that way instead.

[billknny]

Originally Posted by redneckrob

I'm actually engaged in a similar project as we speak. One thing to add to your list is some kind of salinity detector with a relay connection that powers a 3 way diverter valve. This ensure that the product is dumped overboard until the salinity is below the limit you set. You want this to be automated even if nothing else is, because potentially you could spoil your entire freshwater tank if it starts putting out high salinity product and dumping it in your tank. I have yet to be able to source a 3 way valve at 12 volts, so will probably end up with two 2-way valves, one normally open and one normally closed.

Two valves would be a BAD choice. If your normally closed valve was to fail to open (or just open late), and your normally open valve had already closed, you'd block in the product water line, and that would be bad.

This is an issue with some types of three way valves too. You should use a "T-port" valve as a diverter, NOT an "L-port" which can block the product water line if it operates less than instantaneously.

Diversion of product water can be done with ONE one-way valve. The line to the tanks goes up to a vented loop, and the diversion valve is on a tee low down so the head pressure of the loop diverts the water to bilge or overboard. Not fool proof, but better than nothing.

An RO unit is a pretty simple device, but the devil is in the details.

[1affiah]

Why not keep it simple & cheap with a manual y-valve with one leg going to your galley sink, the other to your tanks. Then make a small "lab faucet" for sampling with a chrome/brass toilet inlet valve ( 1/2" FIP inlet, 3/8 compression outlet) with 12" piece of 3/8" chrome brass tubing bent like a "lab faucet".
With the valve open, remove the handle & grind off the stub before installation, you don't need the valve.

Should be about $20.US for parts, then buy a couple of TDS meters for sampling. I wish I could come up with a picture.

[redneckrob]

Originally Posted by 1affiah

Why not keep it simple & cheap with a manual y-valve with one leg going to your galley sink, the other to your tanks. Then make a small "lab faucet" for sampling with a chrome/brass toilet inlet valve ( 1/2" FIP inlet, 3/8 compression outlet) with 12" piece of 3/8" chrome brass tubing bent like a "lab faucet".
With the valve open, remove the handle & grind off the stub before installation, you don't need the valve.

Should be about $20.US for parts, then buy a couple of TDS meters for sampling. I wish I could come up with a picture.

If you know you'll always be around when you're making water then the alarm route is fine. I'm just paranoid of contaminating all my fresh water if the membrane tears during operation so would prefer a valve that autodumped in that case. I suppose you could just wire it to shut off the entire system as well, although you would still want something to divert the initial bad water.

[1affiah]

I'm surprised the more experienced watermaker folks haven't stepped in yet...
BUT..What you describe sounds a lot more likely to fail (at least to me) than the standard, surprisingly durable Dow Filmtec membrane.

[Brewgyver]

Originally Posted by redneckrob

If you know you'll always be around when you're making water then the alarm route is fine. I'm just paranoid of contaminating all my fresh water if the membrane tears during operation so would prefer a valve that autodumped in that case. I suppose you could just wire it to shut off the entire system as well, although you would still want something to divert the initial bad water.

Personally, I don't think I'd ever set up a watermaker to run unattended.

The vast majority of 3-way solenoid valves are made to control cylinders in hydraulics and pneumatics. When energized they allow flow of fluid into a cylinder, and when de-energized stop flow from the source (product water in this case) and open an exhaust port for the fluid to flow out from the cylinder.

What you would need for this application is a diverter valve, and they are not generally snap acting.

As to using two valves, one NC and the other NO, you could find a high-pressure cutout switch and set it at say 1,ooo psi.

[a64pilot]

Originally Posted by Privleoplag

Some one-way flow check valves

What would you do with that?

Reference the auto dump based on salinity, I guess your the guy with the generator Murphy switch in your main engine so that in the event of low oil pressure it auto shuts down?
There is one at least watermaker that I believe continuously monitors TDS and I think shits down if it goes above a set amount.
The one Amel uses I think?

For what it’s worth I’m still searching for an in-line salinity tester that isn’t junk, one I have works fine, until there is water flow then it reads stupid high, and it’s obviously a cheap plastic thing, so it’s unusable. I’m lazy and would like to see TDS at the panel so I don’t have to get up and manually test it and return.
Anyone have a source of a good inline salinity tester, one that isn’t cheap and works well with a large display?

An actual membrane tearing is I believe exceedingly rare, they are often run at around 800 PSI and rated for 1,000 PSI, at least mine are anyway.
You could blow an O-ring, but that is also exceedingly rare as if operated correctly they are slowly brought up to pressure and then the pressure remains constant, it’s pulsating pressures that usually blow O-rings.

[Capt.Don]

Following!
Don

[redneckrob]

Originally Posted by Brewgyver

Personally, I don't think I'd ever set up a watermaker to run unattended.

The vast majority of 3-way solenoid valves are made to control cylinders in hydraulics and pneumatics. When energized they allow flow of fluid into a cylinder, and when de-energized stop flow from the source (product water in this case) and open an exhaust port for the fluid to flow out from the cylinder.

What you would need for this application is a diverter valve, and they are not generally snap acting.

As to using two valves, one NC and the other NO, you could find a high-pressure cutout switch and set it at say 1,ooo psi.

Do you have a source on a 3 way water diverter valve that is stainless or plastic, 12V, and made for water (vice hydraulics or air)? If so I would absolutely love to have a link, I've been searching everywhere for one, to the point I've gone through having 3 different models shipped to me and none of them worked so I had to send them back.

[Brewgyver]

There are tons of suitable valves available, but there are two catches. First, you're not likely to find one that runs on 12 vdc, it's just not used in the fields that use such valves. But if you can step it up to 24 vdc, then you're good, because many of them are available with 24 volt AC/DC actuators.

Second, they are slow, taking 60-90 seconds to cycle. However, if you tailor your choice of valve to match your product water flow, you can minimize contamination by dillution.

Belimo

[Brewgyver]

Hmmm, posted accidentally, wasn't able to edit. Found I had the reply going in two windows...

If you start shopping around, you can probably find it for a little less $. The actuator is about 60% of the cost. Just remember you want the actuator to be ON/OFF Spring Return.

As A64 has mentioned earlier, the major stumbling block to automating rejection is going to be finding an inline continuously sampling TDS meter that will perform per specs at the flow rate needed, but I think they're out there.