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Changing Membranes
Posted: Friday, August 29, 2008 4:54 PM
Joined: 21/04/2008
Posts: 2

How often should I change the membranes in the yacht’s watermaker?

It’s probably been a while, so I’m hoping you’ll be able to share some regular maintenance guidelines.



James Rodgers
Posted: Tuesday, September 2, 2008 1:09 PM
Joined: 29/08/2008
Posts: 2



You should only change your membranes when they are bad, you want to test your product water to determine this. If you have a TDS (total dissolved solids) meter on the boat take a sample of your product water and see what kind of reading you get. If you do not have one they are available for around 50 dollars US. You don’t want to rely solely on your machines salinity probe as they can become dirty thus inaccurate. Sea Recovery watermakers will qualify the water as safe if the TDS reading is below 1000 parts per million.  This threshold can be changed if desired.  If the reading that you get is above 900 then it is time to change the membranes .  The manufacturer recommends that they be cleaned once they are about 10% above their new production quality or 10% below production rate. Once they exceed this point cleaning becomes ineffective.


As for regular maintenance,  


Inspect all hoses for wear, all hose clamps for rust, and all connections for leaks on a monthly basis.

Inspect pumps for leaking oil or sea water on a monthly basis.

Change oil in the high pressure pump every 500 hours.

Change seals & valves on high pressure pumps every 2000 hours.

Change post filters and fresh water flush filter elements every 90 - 120 days.

Change or clean prefilters when a 20 - 25% decrease in post filter pressures or noted.  If you have a pressure prefilter and post filter pressure gauge then clean or change the filters when a 20 - 25% pressure difference is noted. 

If the system has an oil / water separator then this element should be changed when ever oil is evident or every other time you change the prefilter. 

Clean salinity probe every 500 hours or when a sudden change in the salinity read out is noted. 


I hope this helps, if have any other questions let me know.


Best regards,

James Rodgers

Beard Marine