Re: [Amel Yacht Owners] Re: leaking 3 way valve in dessalator watermaker prefilter



Our system is older, and does not have an automated fresh water flush, I don't know enough about that system to give advice.  We flush our system with fresh water manually for three minutes only if we are not going to be using it for more than two days.  Our normal routine is to make water every day. 

I can not imagine any operating tricks that would "fix" the leaking valve... but other people might be more creative than I am!

If your pump output is low, you can get the pressure up but not make as much water as you should.  This can happen if one check valve in the pump is bad, basically taking one piston out of service. If at all possible, measure the rate of the output brine flow. Directing the hose into a bucket with a timer is good enough. In very round numbers, it should be 10X the product water flow.  

If you expect 100 l/hr of product water, and you are getting 50, and you saw 500 liters/hour of brine flow I'd suspect the pump or salt water supply.  If you had 1000 liters/hour or more brine flow, I'd suspect clogged membranes.

If you find lower than normal brine flow, a mechanical repair of the pump is likely required.  If the membrane is clogged, flushing with the right cleaning solution might restore at least some of the lost capacity.

Bill Kinney

---In amelyachtowners@..., <svgarulfo@...> wrote :

Hi Bill, 

Thanks for your reply. Agreed, nothing urgent at this point, and I can run the system ok and not use the automated reverse flush part of the shutdown. According to the manual, that is by switching off the watermaker first and then lower the pressure with the regulatring valve. I understand you would follow the same procedure?

I wouldn't try to fix the valve, but I was enquiring whether it was plausible it would fail by just using it once and I suppose failure in any of the three modes you describe could be triggered that way. Alternatively, and as I read from a previous thread about leaking 3 way valves, I was looking for reports of people who experienced fixing the issue by operating the valve somehow differently. I accept there might be none.

On the subject of performance, i can see the device produces 50L/h, so 50% of nominal capacity, with 23C waters temp, with 530h history. That looks pretty poor to me. No leaks to report, pressure gauge stable in the green zone, output water quality is acceptable to taste, just less volume than expected. This is both running 24V and 230V motors. I looked for air in the filter and I can only see a few bubbles dancing around. I tried to purge them as per Bill Rouse's method but can't get 100% rid of them. I hope that's ok?
Is that symptomatic of anything in particular?


Amel 54 #122
anchored near Hyeres, France 

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