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**bludden** · 23-02-2012, 05:08

The RO unit is next for maintenance. Dissassembly of pressure vessels showed an illogocal orientation of the membranes. Does anyone know the correct placement? I'm guessing the "flow" starts at back right and goes left, comes forward to left side of middle membrane and flows right, crosses to front membrane and goes left but would appreciate confirmation. This is the first watermaker I've owned and it wasn't producing drinkable water when I purchased it. How critical is the direction and why? Also I read that some cruisers use a 20 and a 5 micron filter in series and are able to produce good water in less than pristine harbours. Is this correct? Cheers

**Tellie** · 24-02-2012, 04:18

Your membranes are plumbed in series. The flow direction and order you've described is correct. But you need to verify the high pressure side first of the intensifier, this is the side that feeds the first membrane. Also notice when you remove the membranes the placement of the membranes brine seal and put the new ones back in the same order. The brine seal side of the membrane must be on the feed side or input side of each membrane vessel. This is important because of the design of the brine seals lip. There should already be a 5-Micron pre-filter installed. You can add a 20 Micron in series if you like. On the higher production models it's not a bad idea because of the increased flow. Every harbor is different, I would not recommend operating a watermaker in a dirty harbor no matter how good a pre-filter system is on board. Use the watermaker when you are out cruising and grab a hose when you are in harbor. Also before you invest in new membranes you need to check that the intensifier and feed pump/s are producing the correct pressures and flows first. Shenker will have the specs and procedure for your particular model.

**bludden** · 29-02-2012, 02:44

Thanks Tellie, I'll check the direction of flow of the HP hoses before buttoning up. I was pretty sure something was wrong when two seals pointed at each other...cheers

**Tellie** · 29-02-2012, 07:32

Quote:

Originally Posted by bludden

Thanks Tellie, I'll check the direction of flow of the HP hoses before buttoning up. I was pretty sure something was wrong when two seals pointed at each other...cheers

No problem, if I can be of any help just ask.