Cheapest off the shelf watermaker?

[noelex]

One question- I know that you need to run the watermaker every 3-4 days to keep it happy. But how long a run will it need? We don't have a big battery bank and only really have one day of reserve power. So we would want to make hay while the sun shines, and top up the tanks only when we had plenty of excess power. If we only need to do a ten minute run to keep the watermaker happy, then that's fine, but if it needs a proper blast that could turn out to be a bit of a problem.

Water makers like to be used. The ideal is a 2hr run every day or second day, but you can depart significantly from this ideal without doing much harm.

The longest the watermaker can be left without pickling is 5-7 days between runs. However, you can do a brief fresh water flush instead of normal run. This only takes 3-5 minutes so does not use much power, but does consume some water rather than producing any. If pickled, the watermaker can be left for up to a couple of years, but there is likely to be some maintenance needed if left for such a long time.

If you follow these running practices, good quality water makers are reliable and trouble free in my experience (perhaps we have been lucky). Our second water maker on our last boat made almost 50,000L of water and was still going strong when we sold the boat. The only maintenance apart from filter changes was the replacement of one low pressure feed pump.

 

[dgadee]

We runs ours for 15 mins a day. That enough to keep membranes sweet. I think running little and often is far better for membranes and filters than leaving it a few days

I am more a do it every few days away from other boats. Mainly think about fuel in water - someone may have put washing up liquid on that spill causing it to sink. Probably unlikely, of course.

I would like membrane manufacturer's view. I would follow that.

 

[geem]

Water makers like to be used. The ideal is a 2hr run every day or second day, but you can depart significantly from this ideal without doing much harm.

The longest the watermaker can be left without pickling is 5-7 days between runs. However, you can do a brief fresh water flush instead of normal run. This only takes 3-5 minutes so does not use much power, but does consume some water rather than producing any. If pickled, the watermaker can be left for up to a couple of years, but there is likely to be some maintenance needed if left for such a long time.

If you follow these running practices, good quality water makers are reliable and trouble free in my experience (perhaps we have been lucky). Our second water maker on our last boat made almost 50,000L of water and was still going strong when we sold the boat. The only maintenance apart from filter changes was the replacement of one low pressure feed pump.

If you are in the Tropics, running more often is favourable. Heat kills plankton quickly. If you leave the watermaker more than three days you tend to get bad egg smell. It's the reason why we now choose to run daily when at anchor. Water temperatures here is currently 28 degC. By Oct it will be 30 degC. Even 100ft down, the temperature is the same

 

[Yngmar]

One question- I know that you need to run the watermaker every 3-4 days to keep it happy. But how long a run will it need? We don't have a big battery bank and only really have one day of reserve power. So we would want to make hay while the sun shines, and top up the tanks only when we had plenty of excess power. If we only need to do a ten minute run to keep the watermaker happy, then that's fine, but if it needs a proper blast that could turn out to be a bit of a problem.

Good question. Generally you'll always want to fresh water flush after use. This reduces (not stops) the growth while the unit sits idle, which in warm weather (or worse installed in hot engine rooms - note upper limit of 40°C for Schenker) will grow stuff in the membrane in a day. This flush uses up some of the water you've produced, perhaps 5 litres or so on ours, so if you run a 30L/h unit for less than 10 minutes you'll end up having less water in the tank than before.

The membrane is continually flushed while in use, as much more water runs past than is extracted. PPM levels start high and then drop down during use (so you also discard the first water it makes in a session, usually 2-5 minutes depending on how long it sat).

Lastly, if you know you have plenty of water then you can just re-flush the unit without pressurizing it, which will extend the idle time another few days. This can be repeated several times before it needs a longer run. This is useful if you're in a place where you don't like the look of the seawater and don't want to run it from that.

Edit: Cala Addaia being a great example of the latter - your pre-filters will turn green in seconds

 

[geem]

Good question. Generally you'll always want to fresh water flush after use. This reduces (not stops) the growth while the unit sits idle, which in warm weather (or worse installed in hot engine rooms - note upper limit of 40°C for Schenker) will grow stuff in the membrane in a day. This flush uses up some of the water you've produced, perhaps 5 litres or so on ours, so if you run a 30L/h unit for less than 10 minutes you'll end up having less water in the tank than before.

The membrane is continually flushed while in use, as much more water runs past than is extracted. PPM levels start high and then drop down during use (so you also discard the first water it makes in a session, usually 2-5 minutes depending on how long it sat).

Lastly, if you know you have plenty of water then you can just re-flush the unit without pressurizing it, which will extend the idle time another few days. This can be repeated several times before it needs a longer run. This is useful if you're in a place where you don't like the look of the seawater and don't want to run it from that.

Edit: Cala Addaia being a great example of the latter - your pre-filters will turn green in seconds

Good advice but if you run the watermaker everyday there is no need to flush. We have been doing this for the last 9 months. We only do a fresh water flush if we know we are not going to use it for a few days, say if we are on passage. The pre filter condition is a good barometer of system condition. If they are turning black it's because of dead plankton in the water. This doesn't happen with a daily run cycle. Obviously not fresh water flushing saves a lot of water as well

 

[dgadee]

Flushing seems to depend on where you are. We are now in Greece and I would only think about flushing if I was on day 4 of not running. But I would need to run it then anyway.

I have to say, too, that he crew is now much more aware of water usage so our water use is less than it used to be (more efficient showering).

The negative about watermaking is the noise of the pump. Doing it once every three days or so suits us better - when the engine runs and feeds the invertor.

 

[dgadee]

Ps: there is a Daewoo mini washing machine. I've just come back from doing a month's laundry and wonder ....