Frigoboat Keel Cooling Refrigeration in Temperate Cold water?

[s/v Jedi]

Originally Posted by Frigoboat Info

Jedi: Who knows where debris may come from, but some it we have found has been foreign material from installation, i.e. foam particles, saw dust, etc. There is a filter between the Keel Cooler and the end of the cap tube, but it is not visible. Any debris will never get as far as the evaporator as it will not get further than the entrance to the cap tube or hopefully caught in the hidden filter before that.
Yes, all new Frigoboat Keel Coolers sold in North America now have a filter/drier permanently installed on the liquid line. This will not prevent problems from debris introduced into the system during installation, i.e. if the dust caps are removed and then left to dangle in the saw dust or the ends are then pushed through holes in foam insulation, but is somethig customers have requested and so Frigoboat has responded.

Sure. The entrance to the cap tube is part of the evaporator as you sell it. I called that whole part the evaporator because I do not have the means nor expertise to disassemble and repair that. The fix by moving and tapping was as suggested by Frigoboat so I guess it is known that debris blocks that part. I am sure that your research has showed debris that entered because of sloppy installation procedures, but I am also sure you will have found the debris from the keel cooler as I described. It now kind of looks like you deny this ever happens (happened?) and that you only put the extra filter on for it's looks. Your house lawyer might instruct you to say that but it would not go down well here at CF for that kind of treatment uke: I'm pretty blunt and direct and of tech kind that is incompatible with sales/lawyer kind.

I was rather shocked when I saw pictures of failed keel coolers and as an engineer I know there was room for improvement. I hope that the/any improvements done are functional and not just for show.

[Tortuga's Lie]

Frigoboat,
Thanks for your replies, much appreciated. My system is a few years old and is kind of a hybrid. I bought a used Frigoboat brand BD35 compressor and a new keel cooler and a new evaporator. This was installed about 4 maybe 5 years ago. Last spring, I must have had some moisture enter the system after the winter lay-up and the unit would cycle on and off as the water vapor froze-thawed and froze again. I had an expert vacuum out the moisture and re-charge the unit and it has been good since last summer. This past winter, I installed one of your digital thermoatats and this has been pretty cool to have as I can now see the temperature fluctuations inside the box.
Do you think my unit has one of these built-in dryers?

[Frigoboat Info]

Jedi: It was tech talk that led me to feel the need to explain that debris cannot get to the evaporator because of the micro-bore cap tube. As I said earlier, we don't know for sure where debris comes from, but I'm certainly not denying that debris could come from other causes and not purely from poor installation procedures. Our customers asked for an additional filter/drier on the Keel Cooler and we agreed that it was an worthy extra safe-guard and so had it added. It looks like an ugly wart, and was certainly not added for it's looks!

TL: Seeing that you have a second-hand compressor on new evaporator and condenser and have already experienced a moisture issue, it would be prudent to add a filter/drier as a precaution. Normally this would have been done at the time the system was evacuated and re-charged, but you can add the pre-charged Frigoboat item at any time and with simple tools.

[Tortuga's Lie]

Thanks, I'll do that and replace the o-rings at those existing connections as well.

[Frigoboat Info]

Originally Posted by Tortuga's Lie

Thanks, I'll do that and replace the o-rings at those existing connections as well.

Only replace the one old o-ring that is exposed when you undo the coupling, Tortuga's Lie. Although there is also another o-ring in the end of each male and female half of the coupling, these should never be disturbed unless it is absolutely neccessary. These are sealed in with lock-tite, and unless that threaded assembly is undone very carefully there is a danger of some hardened lock-tite breaking off and causing problems down the line. You can find directions here: http://coastalcoolaids.com/images/Replacing_O-rings.pdf

[skipmac]

Originally Posted by Frigoboat Info

Glad to change the subject, Tortuga's Lie!

If you have a Keel Cooled system you already have a filter/drier, and despite what you may have read, it is not absolutely neccessary to add another at this point merely as a precaution. We would only recommend adding a filter/drier if you are experiencing moisture problems or are replacing an evaporator. Nor is it neccessary to change O-rings unless yours are leaking, which is highly unlikely unless you have an older system which you've been running out of the water or with a heavily fouled Keel Cooler. If it ain't broke don't fix it, because you can do more harm than good with uneccessary "fixes". However, we do have a pre-charged filter/drier available with matching couplings so all you need is a couple of wrenches. We have o-rings available too, and it wouldn't hurt to change the one that will be exposed if you ever have to add a filter/drier.
NOTE: In response to numerous customer requests, all Frigoboat Keel Coolers are now supplied with an extra filter/drier installed on the liquid line.

If I may ask a similar question. I have a new Frigoboat system I'm about to install. Air cooled Capri BD50 compressor, 250H evaporator. Based on this discussion and some posts on other internet sites I was also considering the addition of a filter drier to the system. I think there is one already as there are two bits (IE larger copper sections that look similar to the E53275 filter) in the system that might be a filter.

One is on the compressor unit at the output of the condenser, the other on top of the evaporator just before the cap tube. I assume one or the other of these is a filter/drier?

So preferring to err on the side of caution would it make sense to add a filter at the HP output of the compressor? Would be very easy to do during installation and if it would not have the potential to cause any problems and possible add a little extra chance of reliability I would think it worthwhile.

By the way, I recently spoke to a Frigoboat dealer in FL who insisted that filters were not added to the HP/liquid side of the system?

PS
I love this kind of discussion on the forum. A group of knowledgeable people politely debating an interesting and somewhat complex technical issue relevant to many cruisers.

[Frigoboat Info]

Skipmac: There is no need to add any additional filter/drier on your air cooled unit. There is one already on the liquid line after the condenser, and the item that looks like one at the evaporator is not a filter/drier but simply a means to separate the cap tube from the suction line.
Your Florida dealer is being exceptionally cautious. It is true that if the wrong type of filter/drier is added and is not installed and orientated correctly it can cause all sorts of problems. A Frigoboat pre-charged filter/drier with couplings, installed correctly is acceptable.
Thank you for your positive comments and enjoy your new system.

[skipmac]

Originally Posted by Frigoboat Info

Skipmac: There is no need to add any additional filter/drier on your air cooled unit. There is one already on the liquid line after the condenser, and the item that looks like one at the evaporator is not a filter/drier but simply a means to separate the cap tube from the suction line.
Your Florida dealer is being exceptionally cautious. It is true that if the wrong type of filter/drier is added and is not installed and orientated correctly it can cause all sorts of problems. A Frigoboat pre-charged filter/drier with couplings, installed correctly is acceptable.
Thank you for your positive comments and enjoy your new system.

Thanks for the reply. I was guessing that the copper piece on the evaporator was as you describe.

The other copper piece however wasn't clear to me as a filter since there is also a short second, capped off line coming out of it. I'm guessing that short line is a maintenance port for evacuating or charging the system in case of repairs?

[Frigoboat Info]

Originally Posted by skipmac

I'm guessing that short line is a maintenance port for evacuating or charging the system in case of repairs?

Skipjack: There are dedicated Schraeder valve service ports on Frigoboat systems. Sometimes manufacturers will use one item for several applications to save costs, and that is what you see there. It is just that the extra port on the filter/drier is not required in that application and so is blanked off.

[Richard Kollmann]

Originally Posted by s/v Jedi

Sure. The entrance to the cap tube is part of the evaporator as you sell it. I called that whole part the evaporator because I do not have the means nor expertise to disassemble and repair that. The fix by moving and tapping was as suggested by Frigoboat so I guess it is known that debris blocks that part. I am sure that your research has showed debris that entered because of sloppy installation procedures, but I am also sure you will have found the debris from the keel cooler as I described. It now kind of looks like you deny this ever happens (happened?) and that you only put the extra filter on for it's looks. Your house lawyer might instruct you to say that but it would not go down well here at CF for that kind of treatment uke: I'm pretty blunt and direct and of tech kind that is incompatible with sales/lawyer kind.

I was rather shocked when I saw pictures of failed keel coolers and as an engineer I know there was room for improvement. I hope that the/any improvements done are functional and not just for show.

Jedi, Frigoboat person is correct the horse got out of the barn when they produced the first unit with filter dryer installed in return suction line instead of where it belonged in liquid line as closed to capillary tube orifice as possible. You can not close the barn door now by installing a filter where it should be in liquid line as the blockage item is somewhere in that line. You are now the lucky one, you had blockage and followed their temporary solution instructions by tapping item back out of tube inlet orifice into liquid line and their long term permanent fix by purchasing complete evaporator assembly also a filter/dryer. There are reports where Frigoboats temporary fix seem to work for extended use without replacing evaporator asembly. One reported Tapping on line worked several times until on the last time he fractured the line.
Before permanent solution one boater replaced evaporator twice without installing filter.
All icebox conversion units have lines to be connected but only keel cooler kits seem to experience refrigerant blockages. If there are as he says tens of thousands of this keel cooler in service why are we hearing about so few with refrigerant blockages?

Well the good news is all keel cooler units now sold in US will have filter installed correctly. The other good news is that all other air cooled units have the filter installed correctly and do not experience costly refrigerant blockage troubles.

[S/V Antares]

This is clearly one of the best threads ever on CF.

My "Early .. perhaps Egyptian" Adler Barbor failed a month ago in the Bahamas. The information in this thread has helped me greatly. I think a keel cooler is in my future. Thanks... all of you.

[Frigoboat Info]

Antares: Even though you have a museum piece, it may still be matter of simply replacing the electronic controller. The compressors will go on for ever, but the electronics can and do fail for many reasons. Frigoboat is now the only source for replacement 4-pin controllers, both 12v and 24v, for the older BD2.0, 2.5, and 3.0 compressors, and so if you are OK with the power consumption of your present system, you may be able to get it going again simply by installing a replacement controller. It could also be a power supply issue, and 90+% of the calls for help we recieve end up being power related problems. We have a power supply testing document available here: http://coastalcoolaids.com/images/Po...on_systems.pdf
Of course, a new system would be far more efficient, and a Frigoboat Keel Cooler installation will be in the order of 50% more efficient than your present system.

[Frigoboat Info]

Got enough popcorn there, Sailorchick 34?


Jedi, Frigoboat person is correct the horse got out of the barn when they produced the first unit with filter dryer installed in return suction line instead of where it belonged in liquid line as closed to capillary tube orifice as possible. That horse left the barn almost 20 years ago! You can not close the barn door now by installing a filter where it should be in liquid line as the blockage item is somewhere in that line. You are now the lucky one, you had blockage and followed their temporary solution instructions by tapping item back out of tube inlet orifice into liquid line. For cruisers out travelling and far away from decent service facilities, we suggest trying the tapping method in order to hopefully give them service until a more permanent repair can be made. and their long term permanent fix by purchasing complete evaporator assembly also a filter/dryer. There is also the option of installing a cap-tube filter, and we have those available as kits with instructions. This is a permanent fix and does not require replacing the evaporator. There are reports where Frigoboats temporary fix seem to work for extended use without replacing evaporator asembly. One reported Tapping on line worked several times until on the last time he fractured the line. Oh come on! That’s highly unbelievable. Are you sure that’s not an urban myth? What was he using …. A sledge-hammer?
Before permanent solution one boater replaced evaporator twice without installing filter.
All icebox conversion units have lines to be connected but only keel cooler kits seem to experience refrigerant blockages. If there are as he says tens of thousands of this keel cooler in service why are we hearing about so few with refrigerant blockages? In fact Mr. Kollmann, there have been over 23,000 Keel Coolers sold since they were introduced in 1994, so I think you have answered your own question. The more of any one product that is in existence, and the longer the period over which they have been employed, the higher the possibility of there being reported issues. Basically; the more you sell, the more customer support you have to provide, and we make no distinction between helping an owner of a 20 year old system and one recently put into use. The internet is a relatively recently developed resource, and we are now dealing with increasing numbers of issues as the numbers of systems in use grows and the lines of communication expand and are made more accessible to cruising yachts. As a manufacturer, we have no control over the application, installation, or operation of our products, and whilst we can and do make all sorts of recommendations and rules as to what and what not to do, we see plenty of evidence that many times these rules are bent or disregarded. That’s human nature, but while “being creative” may not result in any immediate or obvious operational issues, there can be accumulative effects that might lead to problems later on.
Well the good news is all keel cooler units now sold in US will have filter installed correctly. The other good news is that all other air cooled units have the filter installed correctly and do not experience costly refrigerant blockage troubles. BTW. That 23,000+ number is for Frigoboat Keel Cooler systems only, and does not include our very popular air cooled models or pumped-water systems

[S/V Antares]

Thanks Frigoboat Info... The Module on my system shows a error code "compressor failure". The compressor was in the boat when It sank in 99' I salvaged it (The boat..They are cheaper underwater!) and had a new module and fan installed. It has served me well but I would like a more efficient system. I will have it checked out by my local Frigoboat guru.

[Frigoboat Info]

I have been really encouraged to find that there are some geeks out there taking an interest in this discussion, so at the risk of boring the shorts off the rest of you, I’d like to delve deeper into some of the issues discussed in this thread.
Mr. Kollmann had challenged Frigoboat’s claim regarding our systems being able to efficiently cool a 20 cu ft refrigerator box using a Danfoss BD50 based system. His statement is that: “Based on 86 degree seawater, 90 degree ambient air, BD50 compressor in a 20 cu ft box at max rpm 24 hours a day to maintain refrigerator temps with an evaporator temp of +10 degree F would consume as much as 156 amp-hrs per day based on R21 insulation and maximum BD50 compressor speed.”
Now, assuming we are to be maintaining a 40F box temp, the heat leak into this 20 cu ft box(as a cube) is: 1/21(K) x 44.208(sq ft surface area) x 50 (delta T) = 105 Btu/hr
From the Danfoss specs, capacity of a BD50 at 10F evap temp and 130F condensing temp = 464 Btu/hr
So it can be seen that the BD 50 compressor can theoretically remove over four times the amount of heat that is getting through the insulation into our 20 cu ft box. (Keep in mind that that is assuming an air cooled system, so with a pumped-water or Keel Cooled system the compressor would have an even higher capacity.) So, if Mr. Kollmann is insistent that the compressor has to run 24/7 to keep up, he must be assuming an extremely inefficient evaporator, and that can only mean that he’s contemplating using a stainless steel evaporator or, worse still, a stainless steel holding plate.
While stainless steel is a very attractive and tough material, it is an awful conductor of heat, and we don’t normally want to use it as a material whose primary function is to transfer heat. Take a look at your stainless steel cooking pots and you’ll see that the bottoms are quite thick, and that’s because they contain a layer of aluminum or copper in effort to get an even distribution of heat. In fact, aluminum can transfer 17 times more heat than stainless steel per unit area, and that is why we primarily use aluminum in Frigoboat evaporators. (We do have two models with a stainless steel cover on one side, but we downsize their capabilities accordingly, and normally use them in fridge boxes only.)
Our largest all-aluminum flat plate, the 380F, has a surface area, front and back of 7.5 sq ft. A very conservative estimate of an aluminum evaporator’s heat removal capabilities (Note 1) is approximately 3 Btu/sq ft/delta T, so with a 10F evaporator temp we have a theoretical heat removing capability of 3 x 7.5 x 30 = 675 Btu/hr.
So, to recap: Heat influx into 20 cu ft box – 105 Btu/hr
Danfoss BD 50 compressor capacity – 464 Btu/hr
Frigoboat all-aluminum evaporator heat removal capacity – 675 Btu/hr
In this example, and considering constant conditions, the compressor, running at max speed only, will run on somewhere around a 25% cycle, which means 6 hrs/day. And at a current draw of 7.39 amps (air cooled, from Danfoss specs), that results in 44 amp/hrs per day (at nominal 12v). This is simply to maintain box temperature, but there is still plenty of reserve cooling capability in hand to be able to cool down foodstuffs or whatever else you may wish to put in the box (I’ll let your imagination take over here …..). And because we have more compressor capacity than we can use at the highest compressor speed, we can use a Merlin Smart Speed Controller to slow the compressor down and let it find the most efficient speed to run at.
Now consider the same size evaporator but made of stainless steel instead of aluminum. Its heat removal capability will only be a theoretical 40 Btu/hr, so it will not even be capable of removing the heat that is entering through the insulation, and the box will warm up during the day. In that case we can assume that the compressor will be running continuously, resulting in a daily draw of 177 amp/hrs, which is close to what Mr. Kollmann has speculated. Stainless steel holding plates perform even more inefficiently, as there are now two more heat transfer processes involved; one from the refrigerant through copper or steel tubing to the solution, then through the solution, and then from the solution through the stainless steel to the air. There are other reasons why holding plates are not recommended for use with these small Danfoss compressors, but that will have to be the subject of another rant.

Note 1: See the refrigeration chapter in Nigel Calder’s excellent Boat Owners Mechanical and Electrical Manual, Third Edition.