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skipgundlach · 25-08-2014, 16:19

Our new Sea Frost installation, other than its voracious electron appetite,
works well...

... when the water cooling system works well.

We had atrocious fouling after many months, here in Vero Beach. Divers say
it is taking them twice as long to clean regular clients' boats; it's the
worst they've ever seen.

So, after a great deal of agitation and contortion in order to clean out the
intake line, we did a straight clorox flush by putting an extension of the
filter intake into a bucket we kept full during the flush. That helped a
lot. We also went to a plastic filter media, the 304 very fine mesh having
started to rot immediately, and got to the point where there was little use
of having it.

In one of several threads I followed on the subject, I learned that swimming
pool chlorine tablets also came in something about an inch high and the
diameter of a quarter; they fit in our filter media.

We started with 3 (higher concentration than with one or two), and all was
well. Except that it totally bunged up with mud and a very small bit of
tiny seaweed (based on appearance), and all the tablets were consumed, in
about 6 weeks - we hadn't checked it before that time had elapsed.

So, we laborious cleaned out, yet again, the intake, eventually getting a
flow again. We put in 2 tablets this time, 6 days ago, and the water is
flowing vigorously again. It seems as though if we just keep SOME portion
of chlorine in the system, it will stay clean. When the pump stops running,
water seeks its own level, and since the compressor is a couple of feet
higher than the pump, and a bit higher than the waterline, some water back
feeds into the through-hull - and, I presume, keeps that free of animal life
(and maybe inhibits vegetable, too, which would be a good thing, given how
fast our filter packs up).

However, on one of the threads (in most cases, about AC lines, but the
concept is identical), there was a caution of free chlorine gas, possible in
this sort of setup, as being detrimental to the copper parts of the system.

Our copper is limited to the coils inside the air/water cooled compressor
box; the rest is regular x-hatch clear hose for the intake and exhaust
sections downstream from the pump.

As this is, apparently, at least in Vero Beach this summer, the only way we
can get water flow without having an hours-long, contorted cleanup on a very frequent basis, we're reluctant to abandon it. Yet, if it's going to cause
a failure of our system, we will have to do just that, and figure out some
other means of keeping the lines clean.

What's been your experience, those of you who've tried this trick?

Thanks.

L8R

Skip

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sailorboy1 · 25-08-2014, 16:33

I haven't tried it

But as a water treater I can tell you that chlorine is detrimental to copper. You would be much better using less tablets and replacing more often so that it results in a lower total chlorine level.

skipgundlach · 25-08-2014, 18:04

My sense of fluid dynamics says that the tablets will dissolve in a period of time/amount of water flow, regardless of how many there are.

So, the time to replace should be the same; the number should determine the level of chlorine in the water.

Or, so I think ☺

sailorboy1 · 25-08-2014, 18:08

Quote:

Originally Posted by skipgundlach

My sense of fluid dynamics says that the tablets will dissolve in a period of time/amount of water flow, regardless of how many there are.

So, the time to replace should be the same; the number should determine the level of chlorine in the water.

Or, so I think ☺

you think so,try it with of couple of alka seltzers and see if 3 dissolve slower than 1

I know for a FACT that more chlorine tablets in a tank will result in a higher chlorine level

your boat do what you want

skipgundlach · 26-08-2014, 05:05

Quote:

Originally Posted by sailorboy1

you think so,try it with of couple of alka seltzers and see if 3 dissolve slower than 1

I know for a FACT that more chlorine tablets in a tank will result in a higher chlorine level

your boat do what you want

I can't figure out whether we're agreeing or not.

If I take a strainer and put in 3 alka-seltzers, and run it under water, do I understand you to say that it will take n>1x the time it does to melt them as compared to just one?

My contention is that they will dissolve at the same rate regardless of quantity, but the concentration of the output will be in direct relation to the number of tablets.

This assumes a constant flow, not static water, of course.

In any case, I'm seeking input from Kollmann; I expect he's dealt with this before (he was very active in my Frigoboat issues, different thread, and I know him from SSCA gams).

In any event, if I come up with any answers from him (or he may chime in on this thread, anyway (FRIGOBOAT seems to get his attention), I'll post them here in followup.

L8R

Skip

biker6977 · 26-08-2014, 05:18

Back to the origianl question- chlorine is bad for copper. It will eat through the copper coil. Try using a chemical such as is used in AC cooling tanks- I don't remember what is used but it will be less harmful than chlorine. Oft times we forget how strong and dangerous chlorine is because it's a common household chemical but it is dangerous- I poured a tad on a spot in my shower years ago and let it soak- it ate right into the stone tile!

Dave Lochner · 26-08-2014, 05:33

Water has a limited capacity to absorb/dissolve other stuff, such as salt, minerals, gases, and so forth. Water temperature has a major effect on its capacity, think dissolving a teaspoon of sugar in ice tea vs. hot tea.

When a given volume of water reaches its saturation point at a given temperature it will no longer dissolve whatever is put in there. This is easy to demonstrate with salt or sugar at home. Get a cup of water and start adding salt and stirring, eventually you'll end up with salty water and a pile of salt at the bottom of the container. Heat the water up and you can dissolve more. (It is possible to make a super saturated solution, i.e., the water contains more than it should, that's how crystals are grown like rock candy. Another discussion.)

So, when the chlorine tabs are placed in the strainer and the water is stagnant the tablet will dissolve until the water in the strainer is saturated or there is a significant temperature increase. Once the water is moving, as when it is cooling the condenser, the concentration of the chlorine drops and the tablet starts dissolving again until the saturation point is reached.

Assuming that one tablet is more chlorine than the volume of water in the strainer can dissolve, then 3 tablets will last longer than 1 tablet simply because there is more chlorine available, it will not make a stronger solution, as the water has a limited capacity to dissolve the chlorine.

Anyway, this discussion is quite interesting as I have water cooled refrigeration and hadn't considered the issue of flora and fauna taking up residence in the cooling system.

skipgundlach · 26-08-2014, 05:36

Quote:

Originally Posted by biker6977

Back to the origianl question- chlorine is bad for copper. It will eat through the copper coil. Try using a chemical such as is used in AC cooling tanks- I don't remember what is used but it will be less harmful than chlorine. Oft times we forget how strong and dangerous chlorine is because it's a common household chemical but it is dangerous- I poured a tad on a spot in my shower years ago and let it soak- it ate right into the stone tile!

In one of the other threads which turned me on to this stuff, a blog was cited; they use HTH, which is bromine, tablets for some of the same sorts of reasons, though the particular entry wasn't very informative about the specifics.

As a former pool user, I'd known about the chlorine tablets, but hadn't heard of the other - and also, since what I had was a large strainer, that there were pellets instead of tablets (hot tub application?) as well. In a pool, you're stuck, as the body of water remains. Here, I don't know what, if any, consequences there would be to a switch after a some-unknown-time flush to get the chlorine out of the system. Do you?

L8R

Skip

**a64pilot** · 26-08-2014, 05:36

This might be a case to try the 5 gl bucket thing? You know fill a 5 gl bucket, put a little antifreeze in it and re-circulate the water in the bucket? Antifreeze should keep anything from growing and isn't bad on the metal.
I do believe chlorine will eat the copper, just a matter of time.

Question is, is will a 5 gl bucket of coolant be enough to absorb the heat?

Dave Lochner · 26-08-2014, 05:52

Quote:

Originally Posted by a64pilot

This might be a case to try the 5 gl bucket thing? You know fill a 5 gl bucket, put a little antifreeze in it and re-circulate the water in the bucket? Antifreeze should keep anything from growing and isn't bad on the metal.
I do believe chlorine will eat the copper, just a matter of time.

Question is, is will a 5 gl bucket of coolant be enough to absorb the heat?

Have someone stand by the breaker and when the bucket is empty, turn the refrigerator off and reconnect the cooling water line.

Another option would be installing a T in the line with a valve. When it was time to flush the line, close the seacock and open the valve in the T and draw the killing solution through the T.

On my boat, the cooling water is drawn through the sink drain seacock. When the boat was on the hard I closed the seacock and ran a hose into the sink to supply water.

sailorboy1 · 26-08-2014, 06:04

[QUOTE=skipgundlach;1614086 Here, I don't know what, if any, consequences there would be to a switch after a some-unknown-time flush to get the chlorine out of the system. Do you?

L8R

Skip[/QUOTE]

Bromine and chlorine are kind of generic terms. Bromine will have the same effect on copper as chlorine. Bromine is a more effective biocide for higher pHs than chlorine and most chlorine tablets are really bromine based type treatment.

I'm not a pool treater. I'm a water treater who treats cooling towers/chiller systems etc. In those systems people think we are treating the cooling tower, but we are really more interested in the much expensive chiller unit (the AC tubes in this case), that is full of copper tubes. There isn't a good answer for a boat system as one isn't going to feed a corrosion inhibitor to protect the yellow metal from the chlorine/bromine. So all you can do is try to limit the corrosion and I feel it is much better to add a small amount once in a while then it is to maintain a high level all the time (a small dose at a continuous rate is as effective as a larger dose for a short time, but isn't practical for a boat to try to maintain). You should really only need to maintain the brocide dose for an hour to kill the bio-film in the system.

skipgundlach · 26-08-2014, 06:09

Thanks, Dave - no quote here, to save electrons.

The water in our strainer, due to the nature of the beast (as covered in other threads here, including an opinion that our system is garbage), is mostly self-refreshing, assuming the tube is clear (as it seems to be, as long as there's some chlorine in it), so I doubt that there is much opportunity for saturation.

I was actually very surprised to see how long it took for this current one to dissolve (at last inspection, it hadn't - or, at least, the circumference view was still totally crisp, rather than somewhat ragged as I'd expect if it were dissolving - a few days into the installation). Our first inspection point is today; I'll have a look and see if the tablets are still there, and what the gunge factor is, after one week of operation.

I can tell you that despite the flow being very weak in the beginning (I can't really get the intake completely clean without heroic efforts, and to clean the length of hoses to the in and out of the compressor box would also be challenging; ergo, the flow is restricted to start), it's gonzo by comparison, now.

I presume that to be a flushing of the gunge via chlorinated water, with, when it DOES cycle, a backwash through the intake as the water in the discharge line seeks its level (the pump is a fixed impeller - water can flow freely in either direction at rest).

My challenge is to keep it clear; I'm guessing, and won't really know without experimentation, that a single tablet, refreshed on about a 50% duty cycle, would do the trick. Whether that level of chlorine in the water is of long-term concern to the system has yet to be defined (opinions from guessing don't get much weight in my scale, but actual pros with history should be able to tell me). Whether HTH tablets (assuming I could find them) would both do the job and not present a hazard also remains to be defined.

But our system, in this water, simply will not work without some cleaning agent either in dilute, constant, application, or heroic efforts at remediation when it clogs (which it definitely will, regardless) AND some cleaning agent applied afterward.

Bleah.

Apparently the same symptoms are found in AC systems, but, perhaps, with the much larger water flow, don't develop as quickly as is the case here. I learned about that, BTW, from a SSCA and Bahamas buddy who was complaining, here (CF) about his AC lines. So, some definitive solution to that would be useful. (I learned of the tablets in the filter in one of those threads...)

L8R

Skip

skipgundlach · 26-08-2014, 07:22

Great thread - my internet is currently so slow I didn't see the others which came in after Dave's first, so didn't comment on that one/those.

As I'm not very good with multiquoting, I'll just address each:

Recirculation is the modus under which Barnacle Buster (phosphoric acid based) is recommended. Unfortunately, we don't have any reasonable means to do that. So, instead, our initial cleaning was to run straight Clorox through until it came out (from a dry-by-blowout tube) the exit. The switch for the pump (allowing air cooling to continue) is within my reach while I'm sticking a tube in my chlorine dish, so I did that for several applications with 5-10 minute perk time. Cleaned it right out, and the stuff which blew out the exit was impressive for its level of solids.

However, getting to the point of being able to do that direct-concentration input is excruciating based on the pump location, and not viable (or, at least, I'm unwilling to do it that way after the first cleanout), and thus the tablets. I agree that running the same water around for a few hours, in a high-concentration "something" environment, would/should do a great job of cleaning. But it's not practical aboard Flying Pig.

As to water pickup, the installer scavenged from our salt-water washdown with a T; unfortunately, that has rendered the SWW system virtually inoperative, as the pump for it pulls the water out of the cooling system, and then pulls air through the exit lines via venturi effect, whether or not the cooling pump is running, so we don't get a good stream for washing. When we're next hauled, we'll remove the keel cooler and install another thru-hull for the washdown.

So, we're currently wrestling with how we might be able to:

1) install a cleanout at the end of a T mounted at the end of the intake, above the thruhull. This would allow us to free the totally-packed intake, from dome filter outside the hull through the access T to the pump, if we don't solve the accumulation issue.
2) install a valve to isolate the cooling system when we need/want to use the washdown system (would require a trip into the engine room, removing the access panel - which, of course, has stuff stacked on it - for the filter, turning off the switch on the compressor box which controls the pump, allowing air cooling to continue, and closing the cooling water intake valve we'd installed, and reversing the process every time we wanted to washdown).

Except that the clearance above the thruhull is minimal for the platform/access panel to fit, limiting the opportunity for a T (unless I could, maybe, find a T with male rather than female ends, to avoid the height of the nipple needed to install a typical T), and the longest piece of hose in the intake system, before a filter (our washdown system has a typical - in fact, it was the original on this boat - engine intake filter, and then another filter similar to the one for the refrigeration, as well), is about 3-4", and the part from the T supplying the refrigeration to the filter is about 2.5" - so, not much opportunity for valves. I'll have to solve the washdown some other way until we are hauled again - which we don't anticipate for years.

As to antifreeze, I have no idea whether it would kill critters, but the chlorine seems to not only kill them but dislodge them as well. I presume that to be in the non-copper parts; seems to me critters and the rest would have a difficult time with pure copper (the cooling lines in the system, not supply/exit lines). If I can't figure out a safe and convenient way to deal with it, my system is even more worthless

than others in differing threads have opined recently :/

L8R

Skip

**a64pilot** · 26-08-2014, 08:46

The antifreeze was not meant to kill critters, but to suggest a closed system that is not circulating raw water, but is circulating a coolant, very similar to how your engine is cooled for example and for the same reason.
I believe it makes as much sense to circulate raw water through your refrigeration system as it does to circulate it through your engine.
Leads I think to one of two possibilities, a twin pump system with a heat exchanger pretty much replicating your engine cooling system on a smaller scale, or possibly circulating the cooling water through a large enough mass of water that the heat is lost as quickly as it's added, maybe as other have suggested using your fresh water tank as that heat sink.

All this assumes that you want liquid cooling, that for whatever reason air to air just doesn't work for you.