Sharing thru-hull between watermaker and air conditioners.

[Sailmonkey]

Originally Posted by accomplice

Do I understand you intend to have a watermaker but no genset to power it? Are you planning on a very large inverter?

If you're only planning on using the watermaker when on shore power, have you considered getting water from shore as well ?

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I have a watermaker and no genset to run it. Nor do I have a large inverter. I have a watermaker that is powered by the batteries that are charged by the sun and wind. My air conditioner is only used at the dock


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[newhaul]

Originally Posted by accomplice

Do I understand you intend to have a watermaker but no genset to power it? Are you planning on a very large inverter?

If you're only planning on using the watermaker when on shore power, have you considered getting water from shore as well ?

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The op stated he would have a spectra wm and they are 12v units we have our wm on the same thru hull with the seawater rinse to the galley. I would recommend a check valve in the ac side of the y

Edit I mid read and it was not the op that stated spectra was another poster.

[accomplice]

Originally Posted by Sailmonkey

I have a watermaker and no genset to run it. Nor do I have a large inverter. I have a watermaker that is powered by the batteries that are charged by the sun and wind. My air conditioner is only used at the dock


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My error. I confused you with the OP. I didn't think the sea recovery aquamatic 900 was available in DC form. I see now that it wasn't you.



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[Sailmonkey]

Originally Posted by accomplice

My error. I confused you with the OP. I didn't think the sea recovery aquamatic 900 was available in DC form. I see now that it wasn't you.



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Your reply without quoting a specific post made it seem as if you were saying all watermakers needed a generator to operate. I was simply pointing out that generators are not needed for running a watermaker.


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[accomplice]

Originally Posted by Sailmonkey

Your reply without quoting a specific post made it seem as if you were saying all watermakers needed a generator to operate. I was simply pointing out that generators are not needed for running a watermaker.


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True. And a DC watermaker probably has lower sea water/brine flow rates and thus could better share a through hull, all else being equal.

[EvilRabbit]

Originally Posted by accomplice

Do I understand you intend to have a watermaker but no genset to power it? Are you planning on a very large inverter?

If you're only planning on using the watermaker when on shore power, have you considered getting water from shore as well ?

Sent from my SM-G930V using Cruisers Sailing Forum mobile app

Yes we have genset and large inverter so will time our watermarking with battery top up

[sailjumanji]

So Tellie (JT), if air is bad for the watermaker, am I causing damage when I clean out the strainer and restart the system with air in there. Ditto for after cleaning the 10 micron filter, as you can't get the air out of that canister either. I do notice it takes a while for the air to work thru and the stroke pressures to get up to normal. The manual doesn't cover this. Anyway, is there something special that needs to be done when restarting after strainer and filter clean, and introducing air into the system.

[a64pilot]

Eb, Understand, I thought you had a genset. A generator changes everything, I didn't see how I could do without one, started out with Honda's, ended up with a built in Diesel.

With a 12VDC watermaker, I see now why you would never run the AC and watermaker at the same time.
I would install a three way valve, one that would make it impossible to cross connect the watermaker and the AC unit, or just bite the bullet and do another thru hull, most likely you will do a bottom job between now and the time you go anyway, then do the thru hull. Spectra pump ain't cheap.
I'm waiting until we go, or very close to it before I install a Watermaker myself, just doing the weekend thing and tied to a dock, it makes no sense to do it now.

[Hobie_ind]

Originally Posted by a64pilot

With a 12VDC watermaker, I see now why you would never run the AC and watermaker at the same time.

This wouldn't be a universal truth and I don't understand why you'd build in that limitation. Many boats with generators still have DC watermakers as if you have lots of solar, it gives you the option of making water off solar once the batteries are topped off. With the generator on, we've run our AC often while running the DC watermaker off the battery charger.

[a64pilot]

There are no universal truths, but as he does not have a generator, that means no AC when there is no shorepower, if there is shorepower, there in my experience has always been water, why make water in possibly a dirty area, when it's right there on the dock?
That comment was not directed at the world, but at Eb

Then take my boat as an example, I have a generator and will have an AC watermaker most likely. I see first throwing as much power into recharging batteries as I can, as I have 185 amps of charger and AGM batteries, that could take pretty much all my generator can make all by itself for a little while, then as the charge rate comes down, I'll make water, and as the charge rate continues to drop, I'll have plenty of power left, why not run the AC if it's warm? So in my case, I want to be able to run my AC and watermaker at the same time, his case is different.


I can see how maybe a boat first got a Watermaker without having a generator, and in that case most likely it would be a 12 VDC one, then later they decided to get a generator for whatever reason, but if at the outset you decide to have a generator, I'd think it more logical to go with a less expensive AC powered watermaker as opposed to a DC one.

[SV THIRD DAY]

Originally Posted by sailjumanji

So Tellie (JT), if air is bad for the watermaker, am I causing damage when I clean out the strainer and restart the system with air in there. Ditto for after cleaning the 10 micron filter, as you can't get the air out of that canister either. I do notice it takes a while for the air to work thru and the stroke pressures to get up to normal. The manual doesn't cover this. Anyway, is there something special that needs to be done when restarting after strainer and filter clean, and introducing air into the system.

To answer properly you have to understand why the air is bad and then you can see when air is ok...vs when it will damage things. Water is not compressible but Air is. So when the water maker is running at pressure (typically around 800psi) and making water big gulps of air bubbles will be compressed after they first cavitate the Hp pump and then flow onto the RO Membrane. As they pass from the high pressure to the low pressure side of the RO Membrane, the compressed air will expand and Rip/tear the microscopic RO Membrane film. Once torn, there is no repair and your TDS will just climb up until you finally need a new membrane.

So Air is only "bad" and hurtful to a water maker when the system running at pressure, but during the start-up process before pressure it built up, purging air out of the system from a filter change, raw water filter chance, etc isn't going to really hurt anything.

[briblack]

we did something similar. had a water cooled seafrost refrig/freezer unit, and a spectra 12v watermaker sharing a through-hull. I did put in a check valve, to keep the watermaker from pulling air in through the Seafrost unit. it did work ok, but . . .
the Seafrost was on steadily, and this provided a good environment for marine growth in the strainer, hoses, etc. eventually this led to excessive restriction, for the watermaker. we changed it to dedicated though-hulls, no further problem for the watermaker

[EvilRabbit]

Really great stuff in this thread, thanks everyone for the insights. Hopefully will help others in the future.

While not cheap, and extremely inconvenient for me as the best haul out is 8 hours away, I believe it's cheaper than repairing watermaker and aircon down the line. Both manufacturers clearly specified dedicated thru hulls needed so this is going to be for my builder's account.

[Tellie]

Originally Posted by ErBrown

Since we don't currently have plans for a generator, at least not one large enough to run our AC, we'd only be running it when on shore power. Water maker would only be run when well away from the funk of a marina. If we had a diesel genset that would probably change my perspective a bit.

I'd prefer to not add another thru hull but definitely don't want to be pulling air through our (eventual) spectra. I guess we could just go with a manual shutoff valve for either side of the Y valve? If making water, shut the AC side and vica versa?

As you can tell, haven't gotten to planning the water maker install yet. Hell, I still have no idea where I'll install the Cape Horn we'd like to buy. We'll get there eventually, but might be "out there" by the time we get to it.

Oh, a Cape Horn Extreme 330 is a different animal. Good choice, and my personal favorite watermaker of all. You can run this unit dry for days and not really hurt it. Though I still would not recommend a "T" off the AC intake I've "T"ed off head intakes, wash down pump intakes, salt water foot pump takes with the Cape Horn Extreme 330 with no issues. Let me know when you are ready to think about an installation and I'd be more than happy to give advice.


www.HaldenMarineService.com

[Tellie]

Originally Posted by briblack

we did something similar. had a water cooled seafrost refrig/freezer unit, and a spectra 12v watermaker sharing a through-hull. I did put in a check valve, to keep the watermaker from pulling air in through the Seafrost unit. it did work ok, but . . .
the Seafrost was on steadily, and this provided a good environment for marine growth in the strainer, hoses, etc. eventually this led to excessive restriction, for the watermaker. we changed it to dedicated though-hulls, no further problem for the watermaker

You might want to think of a Spartan BioGuard system for your seafrost that is running continually. These help keep that clogging growth at bay.

Halden Marine Services – Marine Watermakers, Solar Panels, Wind Generators