I also have a problem with my water-maker, which is the 50l/hr Dessalator unit.  It's probably down to neglect. 

When we bought GUMA the water-maker worked (although when Olivier, who did the survey, offered me the sample to drink I did think it smelled a bit of eggs...).  Then followed two years where we were frequently in marinas where good quality water was available and so the water-maker was not required ... or used.  Such was my ignorance. 

'Use it or lose it', I have been told - too late, inevitably.

So at the end of last year I tried making some water for the first time, really, since buying the boat:

• The sampling tube on the control panel did not produce any water.  I had my sample anyway as I had disconnected the outlet feed from the water-maker to the tank, to protect both the tank and its existing content from contamination, havin g been told not to trust the 'good / bad' sensor on the control panel and remembering the eggy smell. 
• The water emerging from the feed tube was super-eggy!  It tasted OK, but the smell was bad. 

I was advised that there was probably microbial contamination on the membranes and that I should pickle them for a while.  So I acquired some steriliser and, following the instructions in the multi-lingual brochure from Dessalator, infused the device with it.  That was just before spending 4 months in Licata marina for the winter 2014/15. 

As soon as we were in clean seas this season I tried the water-maker again. Rinsing with fresh water, then switching the valve back to seawater and following the instructions:

• The water maker seemed to be acting normally, and I increased the pressure. 
• Nothing from the sampling pipe (as expected from before)
• Nothing from the fe ed pipe to the tanks - which I had again removed to collect whatever was made. 
• Then the device switched itself off - maybe due to excess pressure (I was in the engine room observing proceedings from there - mechanically everything looked fine). 

On subsequent attempts to run the water-maker the device seems not to generate any pressure.  Running on 'open', water is pumped through the system and out through the hull.  On increasing the pressure valve by turning clockwise there is very little response on the gauge, little action in the manometer tube, and, at high pressure settings, no discernable water being ejected through the hull skin fitting. Needless to say, no water from the reservoir feed-tube either. 

It seems to me that the pump cannot be generating pressure - or a protective sensor is stopping it (but not switching off the pump).  

Any thoughts on what has happened , why, and what I should do about it? 

Keith

SY GUMA

Currently in Thasos, N Greece.