Tellie, you there? H2O ???

[englewood]

Tellie, thanks, more good info.

To the sea temp issue...big deal or no?

[SV THIRD DAY]

Originally Posted by Tellie

Yeah sorry for not being as available as normal. I did go to Europe. First vacation in five years cut me some slack<grin>. Of course no sooner than I came back Irma was threatening us down here so I have been a bit preoccupied. I see more premature membrane fails and bio-fouling because the fresh water flush was never properly set up. My input about fresh water flushing is this and is generally for all brands. Unless you run your watermaker every day you need to flush your system after each use. You're not saving enough energy, money, or time, to make not doing it sensible. 20 gallons is way over the top to flush a system unless it is a huge 20,000+gpd. But every watermaker is going to be different even identical watermakers on different boats should have their flush cycle carefully matched to the boats capabilities. The amount of fresh water and time should be determined on an individual basis. Most of this depends upon your boats house pressure pump. These come in all difference capacities as far as pressure and flow go. A boat with a 5gpm flow is going to flush the watermaker faster than a 1.5 gpm pump will. I always check the brine discharge ppms to determine both flush duration and gallons needed to perform a proper flush. At the very end of your flush cycle you should be reading below 1000ppms at the brine discharge. Once you figure this out, this is the amount of time to set your flush for. Then the simple math of time X gpm rated house pump and this will give you a close enough idea on how much fresh water is being used to flush your system. Again, every boat will be somewhat different depending on how the boat is set up and how the watermaker is installed. If the plumbing for the watermaker is elaborate and spread out or the install is short and compact the flush will take either a bit longer or shorter, and the volume will be different. The same with production in warmer and colder waters. Even watermakers of the same brand and size will give different results on different boats. There are a lot of variables. The membrane being one. Even the same size membrane from the same manufacturer will different in production one to another, it's just the nature of the membrane beast. Power curves on identical boats are usually all over the charts, again the nature of the beast because of the ships owners chosen other power systems. So in short, looking for number claims from manufacturers while a good basis to start from are never going to give you the real story in real world application.

Bingo.
It's sometimes assumed that the manufacturers are hiding something or being intentional vague at times but it really is a Boat to Boat and Installation to Installation issue. But I'm in total agreement with Tellie...if you are not making water every day, then it pays to spend a few gallons after each run and do a fresh water flush.

[senormechanico]

Originally Posted by englewood

Bill, yes, very helpful. Always nice to know what the immediate neighbours do.Hoping not to turn this into an anchor debate, if replacing it or moving on, would you go Spectra again?

Having had 3 watermakers on two boats (Power Survivor 35, 80 and Spectra 180), I'd buy a Spectra. No question about it.
Way more efficient and easier to listen to as well.

Edit: Welcome back Tellie, with a comment about flushing.
I flush while watching the pressure and product flow gauges.
When the pressure drops and stabilizes and the product water flow increases and stabilizes, I know the flush is done.
Works for me and has for years. What do you think?

[SV THIRD DAY]

Originally Posted by senormechanico

Having had 3 watermakers on two boats (Power Survivor 35, 80 and Spectra 180), I'd buy a Spectra.

Ah but once you go High Output AC you never go back....

[Lepke]

I operate only in cold water and use a heat exchanger to preheat before the membranes using coolant and some plumbing after the normal heat exchanger. I raise the salt water about 20-30° and drop the coolant about the same. So the coolant is a little cooler returning to the engine, but the temperature gauge reads the same. Doesn't seem to affect fuel usage or engine operation.

[44'cruisingcat]

Originally Posted by Cavalier

Out of interest, how long does the flush cycle take per hour of production? Does the flush run sweet water through directly to wash (I'm assuming salt and gunk from) the salt-side of the membrane, or does it pulse?



Sent from mTalk

It takes the same time and water to flush whether the unit has run for 1/2 an hour or half a day.

As has been said, you don't need to flush if you run the watermaker every day.

There shouldn't be any gunk in the membrane. The seawater goes through a 5 micron filter before the membrane.

[Tellie]

Originally Posted by SV THIRD DAY

Ah but once you go High Output AC you never go back....

LOL, you wish. My dumpster gets filled every other month with high capacity AC watermakers and parts. But I still luv ya man!

[Tellie]

Originally Posted by senormechanico

Having had 3 watermakers on two boats (Power Survivor 35, 80 and Spectra 180), I'd buy a Spectra. No question about it.
Way more efficient and easier to listen to as well.

Edit: Welcome back Tellie, with a comment about flushing.
I flush while watching the pressure and product flow gauges.
When the pressure drops and stabilizes and the product water flow increases and stabilizes, I know the flush is done.
Works for me and has for years. What do you think?

Yes, that was the procedure that was given back in the day. It worked well as the assumption was that once the pressures were down the membrane was obviously flooded with fresh water and you were good to go and for you it has worked great. I always fall back on "If it ain't broke, don't go fixing it" But just from years in the field I have learned that the best procedure is to measure your brine discharge ppm. (ocasionally) It may be something you want to try and compare it against your current procedure. The thing is once the fresh water enters the membrane the pressures will obviously drop but measuring the brine discharge you may find it can still be above 1000ppms. But again, when a customer or CF friend tells me the results you are getting I wouldn't recommend to change a thing. It doesn't take much salt water intrusion mixed with fresh water during the flush to actually start bio-fouling especially when the flushes are done automatically and the watermaker sees far less use than you are giving your unit. Again this goes back to every boat and customer are going to be different and there are just too many variables to say this one way of doing things is best for all. But you are my best and worst customer. You know your watermaker well so it performs and operates well and you know what to do right away if it doesn't. This way you don't really need me. But I'm always here just in case.

J.T. Halden (aka Tellie)
HaldenMarineService@yahoo.com
(954) 5515-7077

[englewood]

Originally Posted by Tellie;

My dumpster gets filled every other month with high capacity AC watermakers and parts.

OK, what would be the top 3 reasons for that?

[Tellie]

Originally Posted by 44'cruisingcat

It takes the same time and water to flush whether the unit has run for 1/2 an hour or half a day.

As has been said, you don't need to flush if you run the watermaker every day.

There shouldn't be any gunk in the membrane. The seawater goes through a 5 micron filter before the membrane.

Just a point to the last statement. It's not a matter of "gunk" The issue is the salt water itself that contains smaller than 5 Micron sea life that is constantly introduced and passes through the 5 Micron filter as soon as you start your watermaker. This is constantly flushed over board through the brine discharge. It comes in and out and as soon as you stop your watermaker regardless if you've run it for 1 hour or 12 hours you are still going to have the same amount of sea life smaller than 5 Micron in the system. This is all a fresh water flush does, it is to replace this volume of salt water in your system with fresh water, and this is important, "slowing" the biofouling down to a managable level that weekly fresh water flushing will suffice. Flushing is not a cleaning procedure but a replacement procedure. A small amount of salt water still in the system mixed with fresh water will start to bio-foul within 24hr. It my take a bit longer to completely foul your system. But left alone long enough it will surely foul your system just as if you left salt water in the system. One more thing many people don't realize is that even the fresh water used will surely bio-foul your watermaker as well if left un flushed for more than a few weeks. There is no such thing as a pristine fresh water tank on a boat.

J.T. Halden (aka Tellie)
HaldenMarineService@yahoo.com
(954) 515-7077

[a64pilot]

Originally Posted by englewood

OK, what would be the top 3 reasons for that?

They are just engaging in some friendly poking at each other, I'm sure