Water maker

[Maravilla]

We are looking at adding a water maker as we transition to living aboard.  Goal is 2-3 weeks out, one week pierside.  Looking at Katadyn 40E due to small size and low amperage draw.  Any experience with this model or alternative suggestions?

[Tafika II]

We have a 2008 Spectra Catalina 300 Watermaker with an MPC-5000 MkII autoflush controller. We have only had two problems... a salinity probe (2) and a PCB which was under warranty. That was 8 years ago. We like the DC system and it supplies our needs adequately. Katadyn bought Spectra a few years back. The service was excellent!

[SeaDarer]

I use a Spectra 400 that runs on 12V.  It draws about 25A and will fill our water tanks in about 8 hours.  At those rates, my solar panels keep up just fine so I tend to run it on very sunny days and thus don’t require a generator or to run the engine at all to use it.  Smaller units will obviously use a lower power rate but make less water.  Overall, I suspect that the power consumed/gallon of water is very similar regardless of size.

My main suggestion would be to get the largest unit that you can fit or afford so that you can make water during the daytime to make maximum use of any solar power that might be available, and secondarily make as much water as you can on each use to minimize the size of the regeneration flush per gallon of water.

Don

[MickeyB]

I use the EcoSystem 35 - 12V and draws roughly 13-16 Amps.

It is perfect for the 2 of us, and we just run it for an hour or so a day to top off the tanks.  I was going for a 60, but the chap who sold it to use said for two people, you have to be serious water users to need more than that (if you are happy to run it for an hour every other day that is).

Mike

[Trevor]

Hello Maravilla,

We have a modified Spectra Newport 400. The modifications were a journey of discovery and can be found in the hints and tips section of this forum.

My wife and I use ( very very roughly) 20 litres per day so don’t need a big watermaker.

I discuss efficiency in the H&T write up. Watermakers are interesting devices.

Regards

Trevor

[Maravilla]

Thank you for the information.  I am not an expert on this site, but cannot find the hints and tips section.  Where is it?

[vasko]

I have Katadyn 80E - extremely happy with it - will never go with another brand - works and works and works 6 years now , no touch no anything just works like Honda - only one important point : next time I will go for 160E 13-15LPH is really not enough... no mater what you think 40E is way way lower LPH then you need

[Trevor]

Maravilla,

Here is the hints and tips article.

www.jeanneau-owners.com/hintsandtips/watermakerinstall.html

Regards

Trevor

[Maravilla]

Trevor,

Thank you, that is an excellent article.  Best regards!

[ianf]

It is an excellent article apart from one major problem I discovered after reading it and then reading the Spectra Ventura installation manual which states "Do Not feed product water into a manifold or bottom of the tank or vent pipe" which is apparently what they have done.

This is possibly the reason why some people have reported lower product water output than the specification due to back pressure which needs to be overcome.

[Trevor]

Yes, I would be keen to hear an actual reason for not injecting product water into the manifold feeding the fresh water pressure pump. Given the column height of water feeding an opening in the top of the tank is slightly higher than the column height of the water feeding the bottom of the tank the pressure is not the problem. The static pressure at least is very slightly higher feeding the top of the tank. Also given the maximum height of water in the tank would be say, 50cm the pressure is under 1 psi in any case. With between 600-800 psi on one side of the membrane and less than 1 psi on the other, it can’t be the static back pressure.

I would like to hear from someone who can explain the physics of what problem is presented by feeding into the suction side of the freshwater system. It certainly provides an elegant solution as it allows an easy way to feed either tank if required using an extra input to existing plumbing fitting. The ease of installation and elegance of the solution was simply too hard for this sailor to resist. 🤓

Regards

Trevor

[vasko]

My installation also injects product water into the manifold feeding the fresh water pressure pump ... 6 years so far no issues

[ianf]

I am in the process of buying a Spectra Ventura V200TC from the USA  and in anticipation have downloaded the installation manual.

 I also think it would be great to plumb the product output into the spare manifold connection for the exact same reason as already stated. I pointed out the section in the installation guide to the Spectra distributer here in the UK which specifically says don't do it and he didn't know why and was going to ask his installer. 

I think I will try contacting Spectra directly. 

[ianf]

This is what I got back from Spectra...


Hi Ian,



Thanks for contacting Tech Support!



Both the brine discharge and the product tubing should be vented to the atmosphere. That is, they should not be routed into parts of the boat that can generate back-pressure. Do not feed into a vent line, manifold, or into the bottom of the tank. There must be no restriction or back pressure whatsoever in this piping.



For this reason the Spectra Factory does not recommend routing directly into a manifold. Back-pressure increases overall PSI on the system and can contribute to erratic production output & premature system wear.





Regards,



Andrew Arietta

Technical Support

[Trevor]

Thanks Ian,

That’s a good response but I must confess to still not understanding. By definition, a vent line is vented to atmosphere. Also, it does take some pressure to lift a water column to the top of a tank. Under static conditions, it is the same pressure to raise that column of water to the top of the tank as it is to lift the column immediately above the bottom entry point. I understand that static head pressure does not necessarily reflect the dynamic conditions when water flows but certainly in my case the flow rate is so low as to almost be negligible.

Good to get the manufactures response though.

Thanks

Trevor

[ianf]

Trevor,

I must say I tend to agree with you but I think I will have to install mine by the book when it arrives in case it invalidates the warranty.

Ian

[MickeyB]

Just thinking about this, I wonder if the problem is actually two fold...

a) There is a column of water above the feed line.  This cannot be atmosphere conditions because there is water above it, albeit very little in the grand scheme of things.  When pushing the water out of the WM, it MUST push the entire volume of water, however small we think that is.

b) When you turn on the taps, the motor will draw water.  This will, in my thinking, lower the pressure as it will try to suck water out of the feed and into the system.  This pressure MAY be the problem they are refering to in the email, as the pressure in the pipe from the WM is now far far less, perhaps negative, to what it expects.

Would be nice to expand further though.