18. Cooling Cures

By Tom Neale, 12/16/2004

Cooling Cures

1. If you’re stuck with compressors which use the “Old Stuff” such as R12, don’t dismay. Repairs aren’t necessarily as costly as some say. Refrigeration mechanics must be trained and licensed to use R 12, and the cost of the product is now prohibitive because of its adverse effect on the ozone layer. While an old R12 unit will mean you’re going to be paying more, perhaps you won’t need to pay as much as some mechanics will suggest. There are so called “drop in” products which will work on the old compressors and which aren’t very expensive. For example, R409A will normally work in the compressors which used R12. Taking out the old and putting in the new still requires the equipment and the knowledge, but you don’t have to pay the fortune for R12, nor do you necessarily have to get a new compressor or completely purge the old.

2. Often a compressor will stop because the refrigerant (I’ll use “refrigerant” to refer to what is commonly called “Freon,” which is a proprietary name and refers to a specific refrigerant) has gradually leaked out. Symptoms may seem to indicate a bad compressor because the unit will run and cool for awhile, and then cut off. The plates may get cold and show frost, although not as much as is normal. If the refrigerant has been gradually leaking over time, its pressure may have gotten just low enough so that, when it gets cold from the running of the compressor and thus contracts in volume, the resulting additional pressure drop will cause the internal pressure in the system to become so low that the system’s low pressure switch simply turns the compressor off.

3. In cases of slow loss of refrigerant, the first thing you can do is to carefully tighten all the compression fittings that you can identify. (Do this after the unit has reached ambient temperature and with the power off.) This often solves the problem of the leak. If that doesn’t work, make a solution of fresh water and dish washing soap and put it over the joints. If you see bubbling, you have a leak. This requires knowing the high pressure and suction sides, but that should be easy for a good refrigeration mechanic and shouldn’t take all day and certainly doesn’t require very expensive equipment. Also, if you find an oily film around a connection or joint, this may be the source of the leak, since the refrigerant normally contains oil for compressor lubrication.

4. When you buy, look for plug and play equipment. This type of gear is making things easier and easier. For example, the Raritan ice maker (609 825 4900 and 954 525 0378) that I mentioned has a plug and play control module to control the rather complex sequence of mechanical events that must occur when any ice maker dumps ice. This ease of “owner repair” is typical of many Raritan products. The Frigoboat, a refrigeration unit that can be installed in insulated ice boxes and which is imported by VecoNA (301 352 6962) is one of several brands sold today which come with the refrigerant included and which have quick connect fittings so that you can easily install it and “hook it up” yourself, connecting the condenser to the compressor when you’re ready. It’s also easy to replace refrigerant.

5. With the Frigoboat system and others, you can buy little cans of refrigerant and filling tubes from most auto parts stores, quite inexpensively, for refilling purposes. Usually they use R134A which is commonly used in car air conditioners. Carry a few cans and the tube with you and you can easily fix it should a leak occur. You don’t have to have gauges. BUT check with the manufacturer first, to be sure you know which port to use and how to determine when you’ve added enough refrigerant.

6. Whenever you add refrigerant to a compressor be sure you’re adding it to the correct port. If you add it to the high pressure side, you could cause the can to explode with devastating effects. Check with the manufacturer to be sure that you know which port to use.

7. Before you take a long cruise to remote areas, it’s worth the money to hire a good refrigeration mechanic and have him check out your system while you watch, and teach you about your system, telling you things that you can do yourself if something goes wrong and there’s no mechanic around.

8. In all cases, disconnect power source unless you must run the unit, and then be careful of dangerous electric shock.

9. I’m not a refrigeration mechanic and you should take these only as general comments about things that I’ve observed as a layman who’s had to deal with refrigeration gone bad while out cruising and who doesn’t like spitting cockroaches.

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Copyright 2004-2005 Tom Neale