Watermaker output low??

[stevensuf]

I eventually got around to installing the katadyne 40e watermaker i bought a while back, it was second hand and had been used a couple3 of seasons then pickled.

After fighting with the pipe to T in (could i get a T the right size?) I powered it up, i had tested it before to make sure it worked with a bucket of sea water.

To cut a long story short, i forgot to put the filter in the filter housing, so had ran it for an hour with no filter.I Put the filter in and it is outputing about 4litres per hour when it should be 5.6 litres per hour.

Just how sensitive are the membranes? would i have clogged it, ie need replaced or will using some ot the membrane cleaner stuff sort it out?

[Strygaldwir]

Actual out put will be determined by a number of factors. These include temperature of the water, salinity of the water and pressure at the membrane. Are the termperture and salinity the same between measurements? Is there a signficant pressure drop after the input filter(s)? If so, changing the filters would help.

You can however backflush your membrane to clear it of obstructing bacteria to some extent. Does your system have a salinity gauge? Some systems reject product output if the salinity is too high. If that is the case, it is probably time to replace the membranes.

[hummingway]

I understand it shortens the life of the membrane to not have the filter in place. In my experience with the 80e there's a lot of reasons why it could be producing less then expected. Any pressure leaks, such as from a loose clamp, can have a large effect. If the amperage going to the unit is reduced then so is the output. I usually run off my solar panels and when the output of the panels drop so does the product.

Cleaning the membranes reduces their lifespan, I would try pickling the thing to flush it and kill the living things and see if that helps.

[stevensuf]

The voltage at the unit is 13.65v water temp 22 degrees, output is 280ppm on tds meter there were a couple of air bubble coming through but not many, kinda rolly here just now.

[Tellie]

You need to run a flow test with both the brine discharge and the product water. Accurately determine the amount made per minute and check it against the manufacturers stated output. Sorry I don't have the 40s flow rate at hand but I'm sure it's in your manual. The fact that it's been used previously for three years and it's been sitting for a while is probably more a determining factor for lower production than the fact you ran it without a filter for an hour. Also finding the source of the bubbles is very important and fix as well. Hydraulic compression watermakers do not like air. Do this first before condemning the membrane.

[Cheechako]

Could be the input water, but likely not if your water is reasonably clean I would guess. Using the old memebrane? You might just need a new membrane...

[stevensuf]

i think the air was from the rolling, i am feeding form the aft heads, which is not too low under the water line, i will try using the membrane cleaner and see if that helps increase the flow rate.

[Tellie]

How far is the intake from the heads to the watermaker? From what you've described I still don't suspect the membrane and you should do the preliminary tests first. Of course I'm not there but my money says it's a flow issue within the watermaker not a membrane issue. Basically with the 30%+ reduction in product water with 225ppms is more indicative of an install issue. A 30% clogged membrane would have high pressure issues as well. You should also take an amp reading at the watermakers terminals as it is running as well and see if it is within the factory specs.

[Sailmonkey]

We have a 40e and have found that any introduction of air kills the output. At the next haulout i'm adding a throughhull near the bottom of the keel just for the watermaker.

[hummingway]

Yes, if air is getting in the inlet the ability of the unit to keep the pressure high enough for the membrane is seriously compromised until it works it way through.

[s/v Jedi]

You can however backflush your membrane to clear it of obstructing bacteria to some extent.

Membranes are cross-flow type filters meaning they have 3 connections and you can't backflush them. Besides disassembling, which might break things, you can flush to clean it by using clean, fresh water as input. First keep pressure off the system (= no pressure), which flushes the main path of salt-in to reject-out, across the surface of the membrane. After that, still with the clean fresh water (no chlorine!), slowly increase pressure just a bit (probably at or under 200 psi) until bubbles stop and you get regular flow from the product output. Adjust pressure for -rated- membrane output which will be around 200 psi on my unit, and let it work for a while.

I use water from my fresh water tanks plus a carbon filter as the source for this. Even when you take in water from shore, most of the chlorine will evaporate out of it after a couple of days in the tanks and the carbon filter takes care of what is left. I prefer RO or ITCZ rain water if at all possible

ciao!
Nick.

[stevensuf]

The pipe run is very short, maybe 3 foot, i will give it a clean with the alkali then flush then acid and give it a longer run, not sure if the air is from the install as obviously there is air in the system at first but i waited till the pipes were fairly clear before measuring output. The 40e is a simple machine , all inbuilt, water in via filter water out reject and fresh water outlets no other pipework

[s/v Jedi]

Originally Posted by stevensuf

The pipe run is very short, maybe 3 foot, i will give it a clean with the alkali then flush then acid and give it a longer run, not sure if the air is from the install as obviously there is air in the system at first but i waited till the pipes were fairly clear before measuring output. The 40e is a simple machine , all inbuilt, water in via filter water out reject and fresh water outlets no other pipework

Steven,

Our calls for not grabbing the chemicals (yet) is because they do actually harm the membrane. You only want to do that when you are sure it's needed. The better approaches to this have already been posted above so I won't repeat them here.

My membranes are now 9 years old and still good, but the only thing that really set them back in output quality is the one time I circulated the chemicals through them and I was sorry I ever did that.

ciao!
Nick.

[nknowland]

This is an old thread so time to find out if it's still active as I have a low output issue from my watermaker.

I have a component system, with a 10gph 120v AC high pressure pump and a 12v DC booster pump.

Year 1. Unit worked perfectly in Bahamas. At 700psi, we made 10gph with 200-280 ppm.

Year 2 and 3 we were off the boat and WM was pickled with sodium metabisulfate.

Year 4. We are back in the Bahamas. Unit is now making only 6 gph at 700psi. The TDS starts at 244 and climbs to 395 after 4hrs of use.

Pumps appear to work fine. Not hot. No leaks. No air bubbles. New filters.

Everyone says the membrane should last for years, but do these numbers mean it should be replaced?

Could it be a pump issue????

Thanks in advance for any and all help.

[Cheechako]

Hard to say for sure, but sounds lie a typical membrane issue to me. They used to say you need to repickle every 6 months... not sure..