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Old 23-08-2004, 04:19   #1
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Refrigeration

REFRIGERATION Help: http://www.kollmann-marine.com
In particular, the thread: http://www.kollmann-marine.com/phpBB...=29&highlight=

Offers a few things to check out yourself, prior to calling the Refrigeration Sevice Tech’. These handy tips could save you a lot of money, by providing the preliminary information the Tech’ may require before coming to your boat.

Excerpts:

Boat refrigeration repair costs are now very expensive because the ground rules regarding refrigerants have changed and there are few qualified service techs. In most cruising areas it is impossible to find a one who is familiar with your type of refrigeration system. A knowledge of what questions to ask when contacting a service tech will pay big dividends. A service technician today will cost from $60 to $80 per hour plus travel time. An average service call can cost $250 or much more if he has to make a repeat visit.
If you can perform a few simple checks of the system yourself before looking for help, you might be able to solve the problem yourself. When checking your refrigeration system, you should look for the following:.

• The condensing unit located on the outside of the box disposes of the process heat of refrigeration by a fan coil, a static air coil or a water tube coil. For a refrigerator to perform correctly the cooling medium air or water must lower the temperature collected in these coils. By touching a condenser coil you will be able to see if they are being cooled. They will feel warmer than body temperature but not hot. Air cooled condenser coils do become restricted with dust and water cooled condensers collect sea growth and require an annual cleaning. Static air condenser coils may require an additional fan in warm climates to remove the excess heat.
• The part of the refrigeration unit that is inside the refrigerator that gets cold is called the evaporator. There are two types of evaporators used in boat refrigerators: a thin plate, generally aluminum and painted white, or a tank type filled with a solution that is know as a holding plate evaporator. The exterior surface of the thin plate evaporator is the best indicator of how the system is performing:
• If the evaporator stays warm in the box there is an electrical problem or a refrigerant problem. If the compressor is running and there is no cooling, then the trouble will be a lack of refrigerant flow. If the thin plate evaporator has a coating of frost covering 100% of the service area, this would indicate that there is enough refrigerant in the system. If the thin plate evaporator is only partially covered with frost then the system is low on refrigerant.

• Large holding plate boat refrigeration systems use a different type of refrigerant flow device with a storage tank to store extra liquid called a receiver. On these systems the refrigerant charge of a system can be monitored by viewing the liquid flowing through a sight glass. Reading the sight glass correctly takes experience especially with some of the new blended refrigerants. It is not necessary for the glass to be full of liquid for the system to work properly. When you see the glass half liquid and half gas, the amount of the refrigerant charge is not causing a performance problem.
• Most of the larger systems use low pressure switches. This means when the refrigerant is low the compressor will cycle off and on repeatedly.
If all of the above items check OK but the box does not get cold enough, the thermostat control may be stopping the compressor too soon.

If you don’t feel confident in doing the above checks or checks don’t show the problem then you might have to ask for help but there are some things you should know about your refrigeration system before seeking help:

• Who manufactured the refrigerator system?
• The approximate age of the system.
• Type of compressor and the model number.
• What type of refrigerant is in the system; R12, 134a, 409B, 404A, R502, R414B, Hot Shot, or some other type refrigerant?
Current history of problems and corrective action.

1. Questions you should ask a repairman before hiring him.
Do you have _____ refrigerant which is the type refrigerant in the system today?
Do you have experience with a _____________ refrigerator?

Do you have an electronic leak detector?

2. Be careful of a repairman if he gives these types of a comments ...

And more ...
I highly recommend the site!

Regards,
Gord
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Old 24-08-2004, 04:11   #2
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refrigeration

If the evaperator is not cooling it can be the problems as stated but could also be a faulty thermal expansion valve or blocked capillary tube.If the cooling on the condenser fails(eg:cooling fan motor fails etc.)then the evaperator will get superheated and the fridge will feel like a food warmer in side. Older Fridges that used cfc R12 in them can be regassed with refrigerant sp34e and there is no oil change or no adjustments required and better head pressures than R134a giving you cheaper repair of the unit many people are lead to believe is a throw away or require costly conversion. Greg.
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Old 24-08-2004, 06:58   #3
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Ozskip, answers like yours are the reason I wrote the article on rising refrigerator repair costs. Weekly I hear of boat refrigerator compressors failing because someone says you can use this or that new type of a refrigerant that is not approved for that system. You must not of read the complete artical on my web site.
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Old 24-08-2004, 23:10   #4
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Richard as a qualified fridgie for over 30years i know what i am talking about and the refrigerant sp34e has been around for almost 10years it is also accepted by all the major compressor companies as a direct drop in for R12 and 134a. It is compatable with both mineral or synthetic gases with good oil return. Greg
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Old 25-08-2004, 02:41   #5
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Thanks !!!

Richard & Ozskip:
Thanks for joining us, and invigorating the discussion with your expertise.
It’s interesting to note, that even seasoned professionals can find subjects for debate and discussion.
Thanks & regards,
Gord
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Old 25-08-2004, 07:52   #6
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Drop-ins May Cause Major Drop-outs

The EPA in this country nor at least one major supplier of most refrigerants, (National Refrigerants http://www.refrigerants.com/frame.htm ) State that there is no such thing as a drop in replacement for R12 refrigerant.

In the US we use mostly LBP and MBP compressors from, Danfoss, Danfoss BD, Tecumseh, and Copland, in boat refrigeration.
I have not seen a bulletin from any compressor manufacturer authorizing the use of sp34e in their compressors. The EPA does except sp34e refrigerant as not harmful but they do not approve it for use in any compressor.

I have read the claims by manufactures of the so called replacements and know at least two of these replacements are involved in compressor damage in hot climates in low temperature boat refrigeration.

It is true that most of these new refrigerants will cool, in some cases they may work for years but in other applications they wipe out the system in days or hours.

The best advice for anyone with boat refrigeration is, Do not use any replacement refrigerant without verifying that the compressor manufacturer has approved it as a replacement.
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Old 25-08-2004, 13:26   #7
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I called Nova kool a few months back asking about the R12 replacement? They asured me that R34a was what to use as long as all the R12 was evacuated and pulled the proper vacuum.
Bill,
Bayfield 32c
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Old 26-08-2004, 06:33   #8
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Some must learn the hard way

I can not believe that Nova Kool engineering approved converting a Danfoss BD2.5 compressor to 134a. If that were a true statement, that 134a was a drop in replacement for R12, then Danfoss would not have needed to design a new compressor, when the manufacture of R12 refrigerant was banned.
I attended an automotive refrigerant industry program in 1996 where we were trained on refrigerants and their oils. This program disagreed with the EPA’s very expensive guide lines for conversion of automobile A/C systems to 134a. Instead of replacing hoses O rings and requiring all the oil to be removed, we were told to vacuum the system, add a conversion oil and service with 134a. An oil company also stated that one refrigerant company converted 50 employee’s cars without using a 134a compatible
oil, without a problem. What might work in the auto-air industry won’t work in boat refrigeration.
There were at that time, and still are today no training programs for boat refrigeration mechanics, so being self-taught they tend to make mistakes including false statements about refrigerant and their oils. These mistakes have proven to be expensive for many boat owners.
After receiving four licenses from EPA approved schools and a certificate from a local automobile A/C seminar I was ready to comply with the new regulations. I changed two Danfoss BD 2.5 compressor systems over to 134a. Both these system failed in the first thirty days, so today I follow the compressor manufacturer’s recommendations. And yes, there is plenty of Freon 12 left to service these small systems.
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Old 20-09-2004, 19:42   #9
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What about freezers?

I was wondering if the same applies to freezers- our Indel B outdoor freezer went on the fritz. It sounds like something is running through it- hissing and such. It just won't freeze again and its only 4 yrs old. I'm wondering if there is any hope of fixing it without hiring a pro...Do they go by the same fridge rules?

thanks for any info,
MPK
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