Water Cooled Refrigeration

[skipgundlach]

There are at least two active threads on our system at the moment.

All center around our air and water-cooled SeaFrost BD80 enclosed-box, forced-fan-ducted-out compressor and condenser heat, system, and the inability of the air cooling to keep up in 90's weather and water, whereas the exact same setup of box and temps was a doddle with a Frigoboat BD50 keel cooled unit using about half the amps of what our current system does.

Those threads have lots to say about how awful any water-cooled (with pipes, vs keel cooler or equivalent) system is compared to air-cooled in terms of cost, complexity, and failure modus (modi?).

So, I'm browsing through threads containing reference to water cooling, and find this:

http://www.cruisersforum.com/forums/...line-8483.html

Richard Kollmann, absent here of late, and not returning my emails (did he die?), also of late, despite many previous correspondences, sez in reply, among lots more commentary over the course of the thread:

Any time the frost line on an evaporator is reduced on water cooled system I recommend pressure testing water tube with balloons for 24 hours with refrigerator off, or look outside boat for small bubbles with compressor running..

Those following my other threads know that our water-cooling line fouls miserably in this Vero Beach Indian River moorage, to the degree that it won't pass water with an open line from the through-hull.

Our solution to the problem has been chlorine pellets which fit inside our strainer; we're experimenting with how often and whether we can get by with one, vs 2 or 3, which will fit inside the media. We know from our first attempt that 3 doesn't last longer, and if we don't put in new tablets after (unknown; our current wait time, with prior tablet consumed, is a week, which is working well, but a major PITA) a while, the line will pack up again.

However, we see, with or without a tablet in the strainer, not only great flow, but BUBBLES!!!!

I'd assumed this to be a matter of the force with which the water left our now-clear line. Richard's comment in a 7-year-ago thread suggests that there may be something else at work. As this is a new (under 9 months old) system, it seems unlikely to be what he's referring to (water intrusion into refrigerant lines), but it's unsettling at minimum.

We're up over our necks in this new system financially, but those following the other threads know that I am - to be charitable - not a happy camper, after MANY months of working on it, which followed truly heroic efforts to save the prior Frigoboat Keel-cooled system which had done so well for the first several years, those efforts involving the US distributor (Hi, Frigoboatinfo), Richard Kollmann, and, in some major hands-on, the company referred to us by Frigoboatinfo, which eventually replaced the FB with a SeaFrost air-cooled BD80 system with water option. When air alone, in December in St. Augustine, would not cool, the water option was added, to my dismay, as it's more amps, and lots of opportunity for mischief, some/most of which we seem to have already experienced, other than a water-jacket failure.

This would be the event which drove us off the boat, I believe, as we can't afford to rip out this $4K system and do it over.

YIKES!!!!

Has anyone had experience in chlorine tablets in filters generating water bubbles? Note that the bubbles were there when we serviced the filter yesterday, and the tablet had been consumed some time before then, so it's not the presence of chlorine, I don't think, which is making the bubbles - but I'm grasping at straws here.

Or, am I correct in thinking that it's merely the volume and speed of the water coming out of the small hole through-hull that's making the bubbles?

L8R

Skip, not yet ready to panic, but fed up to his eyebrows with dealing with refrigeration issues, this now making more than 20 months since our Frigoboat system started to fail, and nearly 9 months of constant messing with our new Sea Frost energy gobbler.

[HappyMdRSailor]

Skip...

Take one (or 5) of these... It helped me immensely...

Both my AC and DC "refreshment systems" are down too...

*sigh*

[a64pilot]

Ain't chlorine, you'd smell it, doubt seriously it's refrigerant as that would be gone quickly leaving you with an inop as opposed to weak fridge, but you know that.
Grasping at straws here, but either cavitation from the pump, or gases from the break down of whatever is in your system and is decomposing? As in methane maybe?
Or I'm thinking on the suck side of your pump you have an air leak and the bubbles are nothing more than air

[skipgundlach]

Originally Posted by a64pilot

Ain't chlorine, you'd smell it, doubt seriously it's refrigerant as that would be gone quickly leaving you with an inop as opposed to weak fridge, but you know that.
Grasping at straws here, but either cavitation from the pump, or gases from the break down of whatever is in your system and is decomposing? As in methane maybe?
Or I'm thinking on the suck side of your pump you have an air leak and the bubbles are nothing more than air

I thought we might have a slight intake seep; the only possibility would have been our salt water washdown. While the system was flowing, we ran the salt water washdown circuit, then closed all the outlets and ran the pump.

Coincidentally, we had to remove the hose from the rear connection; it had a pinhole leak. However, with both pumps off (no washdown or cooling), there was standing water from the pinhole down. As that is the only place where water was evident under pressure, I am guessing that isn't the issue. The pump and connections to it are all well under the waterline, so under pressure, making a leak out, rather than in, more likely.

I suppose it's possible for decomposition, but it's been so long (over a week) that it's run freely, I can't imagine that either. And, other than the amps needed to make it happen, our system is cycling normally, so it's cooling well.

I vote for just volume and splash (really very little as the outlet is virtually at the waterline), but Kollmann's reply in that thread got the wind up my back. As much as has gone not-well with all this, I'm probably gunshy.

L8R

Skip

[a64pilot]

Damn,
I hadn't thought of stray current, not as a source of bubbles, just being what is eating away the condenser.
Wouldn't bonding the condenser coil deal with the stray current?

[GordMay]

Check out Richard's reply:
Skips new Seafrost poor performance problem - Cruisers & Sailing Forums

[sailorchic34]

What size is your tubing used on the water cooled loop and how long is it. Pipe or hose. I'm assuming the through hole is one where the hose slips onto the through hole hose connector. Also what model/size pump do you have. With that information I can calculate the rough pressure drop and flow rate of the system.

[skipgundlach]

Originally Posted by GordMay

Check out Richard's reply:
Skips
new Seafrost poor performance problem - Cruisers & Sailing
Forums

Much going on there; with Dick involved, likely that will be the best; this
one can take a break, perhaps - but the issue of efficacy is being taken up
by sailorchic.

Originally Posted by sailorchic34

What size is your tubing used on the water
cooled loop and how long is it. Pipe or hose. I'm assuming the through hole
is one where the hose slips onto the through hole hose connector. Also what
model/size pump do you have. With that information I can calculate the
rough pressure drop and flow rate of the system.

The pump is as specified by Sea Frost. Their site claims it can handle
another couple of systems, so I presume the flow from a 1/2" intake and 3/8"
output is sufficient, if the lines are clear, which is the case at the
moment.

This is from a tee to a 3/4" input which goes on to the salt water washdown,
now compromised as it has air in it from sucking all the water out of the
cooling line if we use that washdown.

Their literature shows one amp, but Cleave claims 0.7A on the pump.

The feed line (3/8" output) is probably 10' to the compressor box/cooling
line input. The hose is bigger than the pump nipple, so has a sleeve in it
to seal. The out-to-drain line is about 5' or so. Both of those are
half-inch, I believe.

I've duplicated this over in Kollmann's thread, but added runtime information if you'd like to see it.

[skipgundlach]

Originally Posted by GordMay

Check out Richard's reply:
Skips
new Seafrost poor performance problem - Cruisers & Sailing
Forums

Much going on there; with Dick involved, likely that will be the best; this
one can take a break, perhaps - but the issue of efficacy is being taken up
by sailorchic.

Originally Posted by sailorchic34

What size is your tubing used on the water
cooled loop and how long is it. Pipe or hose. I'm assuming the through hole
is one where the hose slips onto the through hole hose connector. Also what
model/size pump do you have. With that information I can calculate the
rough pressure drop and flow rate of the system.

The pump is as specified by Sea Frost. Their site claims it can handle
another couple of systems, so I presume the flow from a 1/2" intake and 3/8"
output is sufficient, if the lines are clear, which is the case at the
moment.

This is from a tee to a 3/4" input which goes on to the salt water washdown,
now compromised as it has air in it from sucking all the water out of the
cooling line if we use that washdown.

Their literature shows one amp, but Cleave claims 0.7A on the pump.

The feed line (3/8" output) is probably 10' to the compressor box/cooling
line input. The hose is bigger than the pump nipple, so has a sleeve in it
to seal. The out-to-drain line is about 5' or so. Both of those are
half-inch, I believe.

I've duplicated this over in Kollmann's thread, but added runtime information if you'd like to see it.

[skipgundlach]

Minor update:

The intake fouls faster than we can keep it clean. It was so bad that it was causing cavitation in the output pump...

Removing the entire input to the through-hull valve revealed the elbow/nipple at the valve was pretty firm with mud or equivalent, even after I'd done some ramming with a SS wire (like a snake) and pumped several times, and the open valve trickled.

I left it open and reamed it until it flowed again. Put it all back together, again, with no clamps, even, as we'd suspected one of the joints or the saltwater washdown into which the pump was teed of leaking to make all the bubbling which came out of the pump, and it's projecting out from the side of the boat. Apparently, if there IS any backwash from the hoses when the pump turns off (set point reached), it's not doing any good in keeping things open.

So, it's not a good option, but the best I have. I'll buy a tee and plug one, or if I can actually get a junction-T, plug two ends, thus making a cleanout available to the line.

Initial appearances are that the very vigorous flow now makes the cycle time much shorter than even before with water.

I'm still having to use SOMETHING to avoid this cleanout being a daily affair, so the chlorine tablets go in every 10 days; I don't know how long they actually last, as it was gone in a week on our first two checks of a week each.

While I'm not the least bit happy about its being required, this will allow me to do the cleanout without a painful disassembly.

[Dave Lochner]

Let me see if I understand you correctly.

The intake for the cooling pump gets clogged with mud at the seacock. It gets plugged at an elbow at or near the seacock, presumably upstream from the filter.

The wash down pump is also teed into the same line and when the cooling pump is running it draws air in through the wash down pump.

If I'm correct there seems to be several things to do.

Remove the wash down pump from the system so the cooling pump does not draw air in through the wash down pump. You could do this by finding a new intake for the wash down or by installing a valve in the line.

Remove the elbow from the system or make the turn softer so there is less disruption in the water flow. In household drain plumbing, this is called a sweep, it is a 90° elbow with a much longer radius. The sweep will allow any debris in the water to move through the fitting with less chance of plugging the fitting.

If the filter is downstream from the elbow that is clogging, I'm not sure what good the chlorine tab is doing.

[skipgundlach]

Originally Posted by Dave Lochner

Let me see if I understand you correctly.

The intake for the cooling pump gets clogged with mud at the seacock. It gets plugged at an elbow at or near the seacock, presumably upstream from the filter.

Almost. The seacock and thru-hull, as well as the area under the hull-side dome filter packs up. That was what I was reaming after removing the ell-3/4" nipple.

Originally Posted by Dave Lochner

The wash down pump is also teed into the same line and when the cooling pump is running it draws air in through the wash down pump.

Well, that's what we thought. But it wasn't that. Even without clamps, the system is now drawing as well as it ever has. Ergo, the static pressure of the open valve is now enough to feed all the pump calls for - and without bubbles. I believe the pump was cavitating, making the air, not a leak-down.

Originally Posted by Dave Lochner

If I'm correct there seems to be several things to do.

Remove the wash down pump from the system so the cooling pump does not draw air in through the wash down pump. You could do this by finding a new intake for the wash down or by installing a valve in the line.

We've thought of that, but it appears unnecessary. The later problem (not refrigeration), as we don't have the room for adding a valve to cut off the refrigeration water, which would solve the suction-pulling-air-through-the-reefer-water-line problem for using the washdown pump, will be to determine how to use our washdown. It's used every time we raise the anchor...

Originally Posted by Dave Lochner

Remove the elbow from the system or make the turn softer so there is less disruption in the water flow. In household drain plumbing, this is called a sweep, it is a 90° elbow with a much longer radius. The sweep will allow any debris in the water to move through the fitting with less chance of plugging the fitting.

Due to the siting of the system, I don't have the height for a sweep, if I could find one. In any case, umpty times, now, bitten, extremely shy.

If I'm going to have to reinvent the intake, I'll want the ability to do a cleanout without having to disassemble the very-tightly-contorted-position system every time (I have no doubt there will more) I clean the lines.

Originally Posted by Dave Lochner

If the filter is downstream from the elbow that is clogging, I'm not sure what good the chlorine tab is doing.

We aren't sure, either, other than keeping critters from growing in the pump-fed lines. Apparently we'll also (still) have to deal with gunge, even if there IS a backwash benefit when the system cycles.