Water maker

A water maker turns salt water into fresh water. This process is called reverse osmosis. Under pressure from a high-pressure pump, water is pumped through filters and finally through a membrane. This membrane is so fine that it even stops salt crystals.

Our goal is to live on water. Autarkic and not having to return weekly to fetch water. Despite having heard varying stories about water makers, we thought it would be a great advantage to have one on board. Of course, after we know exactly how it works.

Because we are on a budget, it was not an option to walk into any marine shop and buy one. A simple water maker will soon cost at least €3,500. This is an entry-level model that makes 6 liters per hour. It is also possible to make one yourself. Although this can be a lot cheaper, the parts can still cost quite a bit. Our solution, (actually as we always do) we decided to put a search on Marktplaats (Dutch Ebay).

For €200, Martijn was able to pick up a Katadyn Power survivor 80E. The device looked dirty and the seller had no idea if the thing still worked. He had just bought the boat and did not want to use it for long trips. A water maker was one of the things he did not need. We took the gamble and started taking the unit apart at home. Online, all the rubbers and other rapidly wearing parts can be bought in a maintenance kit. If the motor gave a sign of life, then the plan was to replace the rubbers and install it in the boat.

The testing phase

The paint was peeling off the casing of the motor. So, we were very curious to see if it would still do anything. After getting the manual from the Internet, we unplugged the motor. This way we could clearly see if the pump was still making the correct movement. Since we had no battery at home, we connected the motor to the car battery. We were lucky! It started pumping right away!

Time to test the overall water maker! To get started at home, we removed the starter battery from the boat. With the manual beside it, we reconnected all the hoses, put salt water in a bucket and turned on the water maker. It seemed to work, only no product water (fresh water) came out. After much searching, the problem turned out to be in the battery. It was too small for the water maker. The result was that the water maker did work, but could not build up enough pressure to actually force water through the membrane. We were afraid of a clogged membrane (these are very expensive if they need to be replaced). Fortunately, it was really the battery that was the problem. We got fresh water just fine, after connecting a larger battery!

Maintenance

Since we had no idea how the water maker had been maintained in the past, we decided to replace all the rubbers and parts included in the maintenance kit. You then have to take the unit almost completely apart. This allowed us to properly clean and inspect everything for possible cracks or other defects.

The piston ring was difficult to get out of the housing. We briefly considered leaving it in. Eventually we managed to hammer it out. Putting everything back together after every part was cleaned and greased was fortunately doable. The biggest challenge was getting it completely watertight or not leaking. Here it was important to tighten the screws crosswise and evenly. Time to test the water maker again. It was quite a relief when we saw product water running into the pan again!

Final test

Of course, it is also important to test the water. If it tastes sweet, it has probably been purified well enough. Especially if you use the water maker on the open sea. Still, it is nice to check the water one more time with a TDS meter (total dissolved solids). This measures the amount of dissolved solids in the drinking water.

The value is indicated in PPM (parts per million). This measurement gives an indication, the smaller the PPM the greater the chance of good quality.

When we put this meter into a glass of tap water, we got a value of 450PPM. A glass of water from the water maker that had been on for 30 min gave a value of 290PPM. Already a lot better than our tap water on the Brouwersdam!

Installing in the boat

In our aft cabin we found a nice spot for the water maker. Because we are still concerned about the quality of the water, we decided not to connect the water maker directly to our water tank. Instead, we pour the water product into a jerry can. We lead the waste water with a hose to the self-draining cockpit.

It was still a bit stressful. At home we had tested everything and the water maker was doing great. Only after the installation in the boat it did not produce water again. This time it couldn’t be the battery, because we had replaced it for a bigger one. We were afraid we had connected something wrong. We checked the manual 3 times, and everything was correct! We didn’t know what to do. What could this be?

After some time searching and mailing with the manufacturer, we found out that air was being sucked in at the pre-filter. There is a 3-way valve which was not airtight. After cleaning, greasing and tightening it, everything worked fine again!

A water maker should actually be turned on every 3 days. If you don’t, there is a good chance that the membrane will get clogged with growing organisms that have remained in the system. For us it would be at least another year before we wanted to start our sailing trip, so we acidified the membrane with a so-called membrane cleaner from Katadyn.