Katadyn 160 Advice Needed

[ksanders]

Hello

I am a very happy owner of a Katadyn 160 watermaker. The advice needed is in regards to the installation.

The watermaker draws water from a through hull with seacock and is located in the lazarette of my boat. The unit is directly adjacent to the seacock and uses the standard single filter setup.

It has a 3 way valve on the seacock side of the filter and a 3 way valve on the fresh water side of the watermaker as well, which will direct water to either a test hose, or to one of my water tanks.

The watermaker works perfectly while at rest. I have a low capacity flow meter installed and get up to 6 GPH of fresh water.

The problem is when I'm cruising, the watermaker picks up small air bubbles. These build up and eventually stop the output. The fix is to use the built in bypass valve to clear the watermaker then go through the watermaker startup process all over again.

The bubbles seem to be coming from the props, and I think they are the normal result of props turning. They are really small but they build up over an hour or so.

I know that the best solution would be to add another thru hull somwewhere foward, but I'm trying really hard not to do that just for the watermaker. What I really want to do is solve the bubble problem some other way.

One possible solution I thought of would be to add a small tank that the watermaker could draw water from. This could be either gravity fed or fed from a pump, but would be set up so it has an overboard discharge/vent line. That way the bubbles would make their way to the top, be vented overboard, and the watermaker would draw bubble free water.

The problem I see with this method is safety. Since the tank would be below the waterline then it would be pressurized with sea water 100% of the time the seacock is open. Thats not a plesant thought.

Any other suggestions?

Thanks

[chrisjs]

I have a similar problem with my AC pump. Have not yet fixed the problem but have thought the solution might be as simple as a "breather tube" that vents air before the pump. Would need an inverted U-bend to "collect" air that then vents from a tube at the highest point of the inverted "U". The vent tube should end higher than the outside seawater and could have a one-way vent valve fitted. If you try it and it works let me know.

[ksanders]

Originally Posted by chrisjs

I have a similar problem with my AC pump. Have not yet fixed the problem but have thought the solution might be as simple as a "breather tube" that vents air before the pump. Would need an inverted U-bend to "collect" air that then vents from a tube at the highest point of the inverted "U". The vent tube should end higher than the outside seawater and could have a one-way vent valve fitted. If you try it and it works let me know.

I thought about that method. At first thought it sounds great...But thinking about it further...

You need a one way valve to keep the pump from sucking air.

The one way valve will have a spring, and will need pressure to overcome it. The air would not supply any pressure.

So, the idea wouldn't work.

I thought of using a vented loop, but they work the opposite of what we need.

I even thought of making a "tank" out of say 4" ABS pipe, and having the top of the pipe be above the water line, but still have a vent going overboard. The inlet from the seacock could be a few inches above the bottom, and the outlet to the watermaker could be below that. The air bubbles would of course go up. Still thinking about that solution.

[Captain Bill]

I find it interesting that air bubbles stop your output,mine just passes them through. It might be the geometry of your set up. My membrane is mounted horizontally above the pump which is also mounted horizontally.

[ksanders]

Originally Posted by Captain Bill

I find it interesting that air bubbles stop your output,mine just passes them through. It might be the geometry of your set up. My membrane is mounted horizontally above the pump which is also mounted horizontally.

Thats an idea that wouldn't take but a few minutes to try.

My membrane is on the same plane as the pump. I could raise it by a few inches by putting it on some all weather wood blocks and give it a try.

Thanks for the idea!