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Old 26-05-2007, 18:01   #1
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Water in refrigerant line

Hi everyone, I had the misfortune that seawater got into the refrigerant line and compressor ceized. I have a 12 volt system with danfoss bd50 compressor air and water cooled. I am getting a new db50 danfoss compressor, a new water cooling copper line. This time I will circulate fresh water from my tanks as opposed to seawater. Meanwhile, should I be worried about the capillary tube at all. I was told to run some nitrogen or CO2 through the system before charging it up with r134a. Another cruiser in the anchorage said that he got rid of the water/moisture by replacing the filter/dryer about 3-4 times in a matter of few weeks. This time I will have sight galss and perhaps a pressure switch to shut the waterpump off as soon as refrigerant pressure has dropped.
Sincerely,
Petar
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Old 26-05-2007, 18:27   #2
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Quote:
I am getting a new db50 danfoss compressor, a new water cooling copper line.
How long did the comprtesor last? They generally go 15 years plus or minus. The compressor itself is sealed and not able to be repaired. Genrall consensus is replace the whole system and don;t reuse anything. The rest of the parts can fail as sure as anything and won;t last another 17 years.

rather than a water cooled unit I would go with the newer keel cooled units. No water pump! Eliminates the problem 100%. The refrigerant is cooled in the keel cooler and you pump no water any place. Given you are in RI, this would be a perfect choice. Air cooled wouldn't be bad either.

So just what do you expect to see in a sight glass?
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Old 26-05-2007, 20:02   #3
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The usual way to get rid of water is to use a vacuum pump.
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Old 27-05-2007, 02:14   #4
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I havenít seen Richard Kollmann on the CF lately; but he is a most knowledgeable and accommodating expert on marine refrigeration I know:
Website: KollmannMarine Boat Refrigeration Specialist
Forum: kollmann-marine.com :: Index
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Old 27-05-2007, 04:00   #5
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Richard Kollman is the de facto source and has very inexpensive books available to help guide you. Here is what I would do, given what I learned from him:

If you are looking to keep it cheap and have tools:

-Drain Danfoss compressor oil out completely and discard oil
-Take apart and dry out all items the refrigerant passes through (or buy new ones) using a lint-free cloth/setup that will not leave anything behind. Concentrate on getting the salt out. You may have to run some distilled water through first to make sure of this.

-Run new refrigeration tubing or use old if you were able to clean it 100%
-Replace filter/dryer (and have a spare around)
-Fill Danfoss up with new oil
-Run nitrogen through system to purge of air
-Use professional quality vacuum pump to purge all moisture. Keep under vacuum for HOURS.
-Fill with R-134a

*If you want to throw the $$ at it, buy a new system, or ask me... I can drive down and do this for you. I have all the tools.

**Additionally, a low pressure switch may not have saved you from this one. A sight glass is important, but once the salt water is in the system, you would have to do the above anyway.
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Old 27-05-2007, 16:19   #6
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Thanks guys
unfortunately we are in Luperon, DR. Providence is my home port that we left in october. I wonder if I should change that.
I have decided to set up refrigeration system to have more control. The fridge craped out in Georgetown Bahamas, about a month ago. And being the complete 12V refrigeration system my hands were tied, and I couldn't do anything about it. I won't let that happen again. This time I am gonna have all the tools and spares to fix the problem. My question was weather the capilary tube is gone or not? it doesn't appear to be alot of water in the system. And most of it was on the compressor side. I pretty much sucked it out with my mouth. It didn't get a chance to go to the evaporator or even to the high pressure copper line leading towards evaporator.

I have orderd the new danfoss bd50 for 204.00 Pretty reasonable. I also got new water cooling condenser, and bunch of other tools and flare fittings. I got 3 filters/dryers because I am sure that I will need to go through a few before the moisture is completely out. I am looking for a good vacuum pump on ebay along with the vacuum gauge service set. Hopefully i can find the nitrogen tank here in Luperon, DR.

I am aware that danfoss is the best and that it should last 15 years. Unfortunately water got in and it was ceized. Than in attempt to jump start it I fried a transistor on the power module(~160$ from rparts.com). I am hesitant to try to revive the compressor especially with the resonable price for a new one.
We'll see after the parts arrive, I try to get the system back to operational. Loosing that fridge in bahamas made our crusing life miserable. Mainly because we never lived without it, so we didn't know how to food shop without the fridge.

Thanks again for the input and I'll keep you updated on what happens.
Petar
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Old 28-05-2007, 05:38   #7
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Throw out everything that has been contaminated with saltwater including the capillary tube ,copper lines and fittings as they are cheaper than wrecking a new compressor. A vac pump will get the moisture out but 34 years tells me YOU WILL NOT GET THE SALT OUT.Greg
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Old 03-06-2007, 15:57   #8
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Sean I was reading your response for the third time now and I had a another question. Options here in DR are limited. But at least there is a very well fitted hardware store that carries all kinds of refrigeration stuff. There are two oils. One for compressor to run in, and one for lubricating the refrigerant line. The one for refrigerant line is supposed to lubricate at low temperatures. When re-filling with r134a, how much of that oil lubricant should go in there? I found a can that has a mix of 2oz ester based lubricant for r134a, and 6oz of r134a. I also have a can or 12oz r134a. Do I need more refrigerant oil that 2oz.
Also if I cannot ship the new compressor to DR, how do I get the bd50 apart to take the oil out and put new compressor oil in?

Apperently shipping to DR is a problem. a guy in the anchorage got charged 100% duty tax going through Santiago.
I might just ship the power module because thats definately bad(i fried it), and try to revitalize the compressor. I know for sure that its seized. Sight glasses and filters/dryers here pretty cheap and available here.

Thanks,
Petar
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Old 04-06-2007, 08:30   #9
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Water cooled refrigerator problem

Water cooling small systems incorporating Danfoss BD compressors is not wise do to the stray voltage discharge into the water. This type of failure seems to occur after five years on live aboard boats and boats with generators or on boats spending time connected to shore power. To avoid salt water one boater used a coil of tubing in an aluminum water tank that was part of the aluminum hull ending up with three feet of hull damage from electrolysis. I have yet to see any specifications or recommendations from Danfoss on water cooling a BD condensing unit. For more information on this subject see FAQ 33 on my web site at http://www.kollmann-marine.com.

Once seawater is pumped through these small systems all components must be replaced; compressor, condenser, lines, filter/dryer, evaporator and its capillary tube. One boater in Panama replaced compressor and keel cooler, flushed every thing else then vacuumed and serviced. Thirty hours later new compressor seized up again.
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Old 04-06-2007, 10:32   #10
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Quote:
Originally Posted by Richard Kollmann
Water cooling small systems incorporating Danfoss BD compressors is not wise do to the stray voltage discharge into the water. This type of failure seems to occur after five years on live aboard boats and boats with generators or on boats spending time connected to shore power. To avoid salt water one boater used a coil of tubing in an aluminum water tank that was part of the aluminum hull ending up with three feet of hull damage from electrolysis. I have yet to see any specifications or recommendations from Danfoss on water cooling a BD condensing unit. For more information on this subject see FAQ 33 on my web site at http://www.kollmann-marine.com.

Once seawater is pumped through these small systems all components must be replaced; compressor, condenser, lines, filter/dryer, evaporator and its capillary tube. One boater in Panama replaced compressor and keel cooler, flushed every thing else then vacuumed and serviced. Thirty hours later new compressor seized up again.

Sorry Petar. I did my best based on what I know. Richard is of course the expert. Do *exactly* what he says.
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Old 05-06-2007, 22:34   #11
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Richard, thanks a lot for the info. Unfortunately I am in the Dominican Republic and parts are hard to get in here. I've heard of people paying 100% duty tax and then some that never got their parts. Shipping a whole new unit is a problem, even just a compressor. We've been without a fridge for a while now and I have decided to try and patch things up with what I got at least until Puerto Rico.
I am gonna try to ship a power module for the bd50 and try to replace compressor oil and flush the refrigerant line. At this point I just want to get the seized compressor running again. For this reason I was looking for the info on how much ester based lubrican should be in the line along with r134a. Also how much compressor oil should be in bd50 after I drain the old one.
Interesting, I just found out that my signal horn for which I have bunch of 12oz cans, works using 100% tetrafluoroethane in those cans. Wikipedia tells me its the r134a. Is that possible?
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Old 06-06-2007, 09:03   #12
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Is it repairable

I understand how you would like to get your refrigeration back on line but the only time one of these systems are completely destroyed is when it experiences a water cooled condenser failure. Cruising boats cruising with different water temperature are far better off with air-cooled BD condensing units because they are far more reliable and generally out last the boat.

You did not indicate the brand of ice box conversion unit you own but here are the problems you will need to resolve if you expect to clean up and repair the existing system:

Compressor
Inside compressor water will rust the over the pumps very little single piston and cylinder and water penetrates field wire insulation. I know of no way to free up a frozen pump piston as the module is limited to 8 amps when powered by 12 volts. The fieldís opposing coils input inside compressor are powered at a lower voltage. Trying to connect external current to compressor to break it lose will destroy one or both field coils. I had three EZ Kool units hear for evaluation with the same type failure water in refrigerant, after cutting top off compressor every thing inside had rust on walls and field coils were shorted to ground.

Refrigerant Oil
The oil in a BD50 compressor is Polyester which is required for 134a refrigerant. All refrigerant oils absorb moisture but it is very difficult to get water to separate from ester oil even under a deep vacuum. The BD50 compressor new is serviced with 150 cubic cm of oil this is enough for a small evaporator system.

Condenser
Frigoboat, WAECO and Isotherm I donít believe use dual condensers air and water so if your unit was water cooled only, you must replace the condenser. If unit also had a air-cooled condenser bypassing water cooled and flushing air-cooled should make it serviceable as long as its inside tubing is copper.

Evaporator
If your system has the conventional aluminum thin plate evaporator water on the interior service will cause the pure soft unprotected tube to oxidize. As refrigerant is a wonderful cleaning agent the white corrosion caused by moisture in evaporator will be wasted off and moved through system until it reaches capillary tube where it forms a paste plugging tube. I do not know how this milky solution gets through the filter dryer but it does. The only way to achieve the velocity to flush one of these roll-bond evaporators is to remove the capillary tube and this is impossible unless you have a Nova Kool system evaporator.

Refrigerant
Tetrafluoroethane is 134a and can be used as a propellant because it is moisture free. What is needed in a refrigerant is a liquid with a low boiling point and tetrafluoroethane has a boiling point of -26 degrees C (-14 degrees F).
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Old 06-06-2007, 16:21   #13
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This is all very usefull stuff. Thank you very much Richard. It is interesting that mine is also EZ Kold. Three yers old. There are no anodes in the heat exchanger and Marvin told me there shouldn't be any. I decided not to get a new unit from him and to try to get this one running and then eventually, build my own. I will not get a heat exchanger then. I will invest more on better air circulation through condenser. Since danfoss is known to be very reliable I want to give it a try and see if it will start. Meanwhile I have already ordered a new compressor and its at home in Rhode Island. From there I will end up shipping it to Puerto Rico.
From your description, I get the picture on how bad things are inside.
As far as the coils, I measured resistance between any two of the three terminals on the compressor. Its around 2 ohms. The coil resistances should be low, does 2 ohms sound like a shorted coil or normal?
That singal horn can is around 95psi. I just blew a can of signal horn gas into the evaporator and the hoses, and some water came out the suction side. Very little though. The water that came out is clear and clean. Seems like there are no rusty stains on the inside.
Unfortunately when I used another can to blow into the suction side of the compressor and out through the discharge, a lot of water came out, grayish color. This is terrible. I am really sad to see so much water come out. This really sucks. I will not use the water cooling ever again.
Now that I blew most of the water out, is there any way to replace oil in danfoss bd50?
Thanks a lot for all your input and answers, I'll update the list on weather I was able to start the compressor or not.

Petar
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Old 07-06-2007, 07:09   #14
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Seawater in Refrigerant

There is a cutaway picture of an EZ Kool condenser failure in my 12/24 volt refrigeration book where the electrolysis was confined to an area of the water tube bend touching outer tube that caused the tube to last only two years. I was informed by EZ Kool that this was an isolated case so I ask if they wanted me to send them two more of their failed condensers , No Reply to my email. When I started my refrigeration shop 25 years ago I sold seawater condensers manufactured by a large east coast company. One live aboard still today in Beauford gives me a bad time about the three condenser failures he had with the units I sent him. The first indication that electrolysis is attacking a water cooled condenser is slow loss of refrigerant as the leak begins with a small pin hole caused by a low voltage spark. Water normally doesnít enter the refrigerant circuit until most all refrigerant has leaked out because these leaks are in the high pressure side of system. 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..

If the resistance between terminals on compressor is 2 ohms and no continuity to ground that is good news electrically. To drain oil/water mixture from compressor remove the valve core from servicing port on top of compressor and turn compressor upside down.
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Old 07-06-2007, 14:36   #15
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Quote:
Originally Posted by phorvati
This is all very usefull stuff. Thank you very much Richard. It is interesting that mine is also EZ Kold. Three yers old. There are no anodes in the heat exchanger and Marvin told me there shouldn't be any. I decided not to get a new unit from him and to try to get this one running and then eventually, build my own. I will not get a heat exchanger then. I will invest more on better air circulation through condenser. Since danfoss is known to be very reliable I want to give it a try and see if it will start. Meanwhile I have already ordered a new compressor and its at home in Rhode Island. From there I will end up shipping it to Puerto Rico.
From your description, I get the picture on how bad things are inside.
As far as the coils, I measured resistance between any two of the three terminals on the compressor. Its around 2 ohms. The coil resistances should be low, does 2 ohms sound like a shorted coil or normal?
That singal horn can is around 95psi. I just blew a can of signal horn gas into the evaporator and the hoses, and some water came out the suction side. Very little though. The water that came out is clear and clean. Seems like there are no rusty stains on the inside.
Unfortunately when I used another can to blow into the suction side of the compressor and out through the discharge, a lot of water came out, grayish color. This is terrible. I am really sad to see so much water come out. This really sucks. I will not use the water cooling ever again.
Now that I blew most of the water out, is there any way to replace oil in danfoss bd50?
Thanks a lot for all your input and answers, I'll update the list on weather I was able to start the compressor or not.

Petar

You could always thank him for his help by buying one of his books when you return... I found his Do It Yourself refrigeration book to be of an almost incredible value. It helped me take a refer in pretty rough shape and get it working in this boat. Now it runs perfectly.

Also, I'll be building his twin holding plate Sankyo compressor system in my next project powered off of a 12HP Yanmar diesel (which will power a couple other things too). The book I have saved me about $1000 in referigeration tech guy costs. I think it cost something like $25. It was a no brainer.

PS: I'm not associated with Richard Kollmann at all. Just a huge fan after having bought the book and found all the info I needed inside.
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