Good Sam RV Travel Guide & Campground Directory

Mark...My Words



Hi, folks! I have a bunch of refrigerator questions this month. The RV refrigerator is the source of a lot of frustration and confusion, especially for new RVers. I hope that some of these common questions and answers will help you with any refrigerator issues you may have.
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Mark:
We have a 2008 Puma travel trailer. It would be convenient if we could start the reefer and let it run while traveling on the road to our destination. If we did this, it would be cold when we arrived and set up the trailer. Could there be a problem running the refrigerator, using propane for operation, while traveling? Your thoughts/comments would be appreciated. Thanks, Richard.

Hi, Richard,
Operating the refrigerator on propane while traveling is one of those controversial issues that will always stimulate a lively discussion around the campfire. Most RV refrigerators will operate quite effectively on propane while you are rolling down the road. Most refrigerators will not have problems with the flame blowing out, and the constant motion keeps everything flowing smoothly in the cooling system, so, technically, it is no problem to run them. The key issues are safety-related: There is an open flame back there in the refrigerator compartment, so it is absolutely critical to shut the refrigerator off before you approach any kind of fuel-dispensing facility. In fact, before you approach a fuel station or propane fill station, all appliances that are capable of producing a flame or a spark must be turned off. Also, the fact that the propane must be turned on at the tank in order to operate the refrigerator may create a hazard in case of an accident or even a tire failure. If anything happens that creates a hole, crack or leak in the propane supply piping in the RV, you have an instant fire/explosion hazard just waiting for a spark. It really is safer to drive with the propane supply turned off at the tank. Most folks find that, for the average trip, the refrigerator will maintain a low enough internal temperature to keep your food fresh. It is also possible to freeze some Blue Ice packs the night before and use them in the refrigerator compartment to help keep everything cold while traveling.
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Dear Mark,
Would you recommend connecting an inverter to the DC lines that power an RV refrigerator and plugging the AC power cord into it while being in transit to avoid the hazards of traveling with the propane in service? Respectfully, Norm

Hi, Norm,
Running the refrigerator on an inverter is generally a good option for motorhome owners but somewhat problematic for trailers and 5th-wheels. In most motorhomes, your house batteries are charged by the vehicle's alternator while driving, and the charge wiring is usually fairly large-gauge. That means that the alternator is capable of supplying a lot of amps to the battery bank on demand. That is a good thing, because the electric element in most RV refrigerators will draw between 250 and 500 watts, depending on the size of the refrigerator. An inverter is going to draw 25 to 50 DC amps to operate that element. That means you must wire the inverter directly to the battery bank, using appropriate-sized wire to support the large current draw. It also means that you need to be aware of the demands your inverter will be making on your house batteries when the engine is off. (When the engine is running, the alternator should be able to keep up with the demand.) This is a great way to keep your refrigerator running safely while traveling since you can keep the propane turned off at the tank. Why is it a problem for trailers? Most trailers have a wire that runs back from the tow vehicle alternator, through the lighting umbilical cord, and to the trailer's house batteries. Unfortunately, the length of the wire, and the fact that it is a small-gauge wire, generally limits the current available from the tow vehicle alternator to 10 amps or less. Because of this, your inverter will run down your trailer's house batteries if you try to run the refrigerator since the incoming charge is not enough to keep up with the load. Trailers with large battery banks and solar panels may be able to support an inverter/fridge setup while traveling, but most rigs with standard equipment won't.
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Mark:
Can a Dometic fridge leak fluid over time or get “tired”? We have a 1996 Trailmanor with a fridge that takes a long time to cool down (4 to 5 hours) even though the heat coming off the back is very hot. Also, the trailer had not been used in 1.5 years. Jan

Hi, Jan,
It is normal for an RV refrigerator to take some time to cool down from a hot start, so you may not have a problem. However, due to the age of your refrigerator, you are probably getting close to the end of its life. RV refrigerators, like any appliance, have a service life. Most refrigerators only last 8-10 years, with a rare exception making it to 15 or more. Corrosion is often the killer, but when the cooling system rusts through, that usually completely kills the refrigerator. When a refrigerator starts to cool poorly, small obstructions in the cooling system may have accumulated over time, making the refrigerator less efficient. There might also be a problem with the heating element or propane burner that is contributing to poor performance. Given the age of your refrigerator, it is probably time to start saving up your pennies for a new one. If your refrigerator is still in really good condition inside and out, with no rust or damage, it is possible to have it refurbished with a new cooling system. This is a lot less expensive than buying a new one. Check out the links below.
www.rvrefrigerator.net
www.rvcoolingunit.net
www.rvcool.com
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Mark:
We have a 2008 31RKLE Cardinal 5th-wheel with the fridge in the slide. During hot weather the temps rise as high as 44 degrees. We have never heard the two fans come on; they are installed about midway in the compartment behind the fridge. We wired them directly to a switch that we mounted inside a cabinet next to the fridge. We turn them on for various periods, sometimes as much as hours at a time. We also have a small battery-powered fan inside the fridge. We keep the temp setting on 5, which is the highest setting. We limit the number of times we open the door to morning, noon, and evening. We try to arrange items to allow for good air flow, but nothing seems to help. The freezer works fine. Overnight, without us opening the door, the temp will go down to 33 degrees but will rise quickly during the day. Could our problem be an improper installation? That is, either having too much or too little space between the coils and the outside wall of the RV, thereby not allowing proper air flow to the coils? Thanks, Vince

Hi, Vince,
It has been my experience that all RV refrigerators struggle somewhat during hot (100 degree-plus) weather. If your refrigerator works fine when it is cooler, it may simply be that you are expecting too much from it when it gets really hot. If it will maintain 40 - 45 degrees in hot weather and the freezer compartment stays frozen, that is actually pretty normal. In really hot weather, it may cool a little better on propane. In general, adding a fan to help move more air upwards in the compartment behind the refrigerator can be helpful, but it must actually increase the air flow from the bottom vent inlet to the top vent outlet to be effective. Check the compartment for anything that might be blocking the airflow, like a clogged screen in the roof vent or a piece of insulation coming loose. Unless the manufacturer really did some bad design work, the shape and size of the compartment should be adequate for the refrigerator, but there are always exceptions. You can download the installation manual for your refrigerator from the manufacturer's website and check the clearances yourself if you suspect that is a problem with the installation.
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Mark:
I keep reading articles about refrigerator troubles, and I fear the worst. In the spring we purchased an older travel trailer, and everything was in excellent condition. The last two times this fall using the trailer, we noticed an odor coming from the inside of the refrigerator. We thought it was something that was used when cleaning it, but we also realized it wasn't cooling very well. I called a local RV dealer and they said it definitely sounded like a leak. Needless to say, since we had plans to go to Florida this winter, we ended up having a new refrigerator installed. I've heard that while traveling there is enough movement of the refrigerant, but when you stop it should be perfectly level or turn it off. Now every time we stopped to eat or shop during our holiday vacation to Florida, I would sometimes forget to shut it off; I would then worry about the fridge and pray I wouldn't smell ammonia. Do I need to be this worried? What does everyone else do? Don

Hi, Don,
There are actually two issues involved here. First off, corrosion is what usually causes cooling system leaks. Some part of the cooling system rusts through, and the ammonia-based refrigerant leaks out. This is generally related to age of the appliance and the manner in which it was used over the years. Some folks feel that refrigerators last longer if they are operated continuously rather than used only occasionally. I'm not sure that is true; I think the climate your RV is stored or used in plays more of a role, with high humidity areas or areas near the ocean being prime locations for encouraging corrosion. In general, operating a refrigerator off-level does not lead to cooling system corrosion or refrigerant leaks. It does lead to an entirely different sort of failure: a clogged cooling system. This is where the system is still full of refrigerant, but something has happened to stop the circulation. When the refrigerator is operating, a heat source, either a propane flame or an electric heating element, boils a liquid refrigerant in a small boiler, turning it to a gas. This gas then travels up to the top of the cooling system, where it condenses back into a liquid and returns to the boiler to complete the cycle. The condensation process draws heat away from the freezer and refrigerator compartment, and that is how the system works. (That is a very simplified description but is adequate for our purposes.) If the refrigerator is operated significantly off-level, that liquid can run to one side of the boiler, causing the boiler to overheat, and this can lead to crystals or flakes of material forming in the boiler. Some of these bits can break loose and float around inside the cooling system and can eventually build up like plaque in an artery and cause a blockage. Once that happens, the refrigerator will no longer cool. I believe that this sort of damage is cumulative. The more hours that a refrigerator operates off-level, the more damage accumulates, and eventually it dies. I make it a rule to always shut off the refrigerator any time the RV is parked in an off-level condition, even if it is only going to be for 15 minutes. How level is "level”? I consider anything more than a half bubble off to be excessively out of level for refrigerator operation. I travel with my refrigerator running on an inverter and the propane shut off, so I try to always be aware of where I park and how level it is. This is only an issue when you are stopped. When you are driving, the continual motion of the coach keeps everything in the refrigerator cooling system sloshed around, and that should prevent any problems with the cooling system.

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Mark Nemeth has been involved with all things RV for more than ten years, including almost 5 years on the road as a fulltimer. Nowadays, Mark is parked for a while and works on staff for the Escapees RV club as technical advisor, consumer affairs director, and instructor in the Escapees RVer's Boot Camp program.



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Please remember, material will be edited. Because of the large volume of material and correspondence submitted, individual replies will not be possible, nor can we acknowledge receipt of your material. Selected questions will be answered in future issues of the Woodall's/CampingLife Navigator newsletter in the Mark, My Words column.

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Some content previously printed in Escapees magazine, published by the Escapees RV Club. All material provided by Mark Nemeth, Escapees Magazine Technical Advisor and Boot Camp Instructor. For more information about the Escapees RV Club, please visit www.escapees.com or call 888–757–2582.

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