by Lauren Lynch
Propane refrigerators are quite different from the home models we’re used to. The gas refrigerators that come in RVs take a little getting used to. Once we understand how they work, though, they can be a safe and efficient way to store enough food to last a week or more.
HOW AN RV REFRIGERATOR WORKS
I was surprised to learn that the cooling process in a propane fridge begins with a propane flame! It heats a sealed chamber with a mix of water and ammonia to a boiling point. Ammonia gas rises to another chamber where it cools to a liquid, then flows into an evaporator where it is mixed with hydrogen gas. This creates a chemical reaction that absorbs heat (from inside the refrigerator). The absorbed heat causes the ammonia to become a gas again, and this whole process continues again in a loop.
Because the cooling properties are accomplished by gravity and circulation, RV refrigerators must be level to operate properly. They can only be off three degrees side to side and six degrees front to back to work. Exceeding that can permanently damage the fridge. This is not as much of a problem during travel, but does become an issue once the RV is parked in a campsite for a while (although it is worth noting that a 14% grade is about eight degrees off-level, so it is a good idea to keep it off for mountain travel, but we discuss traveling with the refrigerator on in more depth later in this article). Damage to refrigerators generally happens slowly over time. If your RV is not level, it may not cause damage to the fridge immediately, but the damage caused is also not going to magically go away either.
The two most common RV refrigerator brands are Dometic and Norcold. Our Coleman RV came with a mid-size Norcold fridge/freezer combo — a gas/electric with automatic switch over. If electricity is available, it will use it. If the refrigerator is left on during travel, it will automatically switch over to propane.
We keep our RV plugged in when we’re at home, so when we’re ready to head out on a trip, I just close up the fridge and turn it on a couple of days before we leave and let it fully cool before loading it. I put room temperature drinks in first and allow them to grow cold before adding other pre-chilled items. I add water-filled ice trays to the freezer and once they’ve frozen, I add in other pre-frozen items.
HOW TO CONTROL THE TEMPERATURE
Adjusting the temperature of an RV refrigerator varies by model. Some have a button on the outside of the near the power switch. Others have a temperature dial inside or a sensor on the fins inside the refrigerator. Norcold refrigerators like ours (N611 or N811) are fully automatic. There is no temperature control dial inside. If you have this type of fridge and need to change the temperature inside, slide the thermistor up on the fin to make it colder and down to make it warmer.
What and where is the thermistor? Duck down and look inside the top back of the refrigerator for the “fins” — a row of metal plates. (To me, they look more like gills than fins, but who am I to argue? It is a row of flat appendages, so fin it is.) Experiment in small increments with its location at a time when you don’t have to use the fridge. This is a great opportunity to put lettuce in various locations of the fridge to find the most ideal place to store it. The idea is to get the temperature nice and cold without freezing anything. Ideally, this is between 33-38 degrees. I bought a thermostat for our fridge so I can keep an eye on that.
About lettuce. On our first trip, I stood a package with three heads of romaine against the back of the fridge. Bad choice. It was frozen by the time we arrived at the campsite. (On that first trip, we also kept the refrigerator running on propane during travel, but more on that later.) Wrap the lettuce in a paper towel, then put it in a ziplock bag and squeeze out as much air as possible. Heat rises, even in a refrigerator, so the bottom of the fridge will be the coolest (so the “crisper” drawer may make your veggies a little too crisp … as in frostbitten). The door will be the warmest. For best results keep your fridge between 36-38 degrees.
RV refrigerators work best when there is plenty of airflow between items and not overloaded. Allow the fridge to cool for at least a day before departing. If only cooling it for one day in advance, make sure the items you place in it are already chilled.
We have a travel trailer, so while we’re on the road, I take along a cooler backpack full of drinks, sandwiches, and snacks for the trip. We don’t open the refrigerator until we’re onsite and plugged in.
FOOD SAFETY
To be safe, you can buy a refrigerator thermometer to make sure the temperature stays between 33 and 40 degrees according to your preferences and the type of foods you are storing. According to the FDA, some foods begin to spoil if the temperature goes above 40 degrees for a few hours. I put meats in the freezer and thaw them the night before use to be safe.
Do I need to keep the gas on while traveling?
For us, ideal RV travel doesn’t involve traveling more than 7 or 8 hours a day tops (preferably much less). I freeze all the meat before we leave on the trip and it will remain frozen for hours with the fridge off for travel. Even the refrigerator remains cool. A pre-cooled refrigerator should only lose about four degrees every eight hours once it is turned off for travel—even on a hot day.
LEGALITIES OF DRIVING WITH PROPANE
Is it even legal to have a propane fridge on while driving??
There are no laws against it in most states (refer to the list below) and it is often left to driver discretion. In the beginning, we kept our propane on during travel. The risk of anything going wrong is low, but accidents do happen (even something as simple as an object in the road bouncing up could potentially break a gas line. However, there would need to be a pocket of gas and a spark to ignite the gas to make it dangerous). Even though we believe the risk to be extremely low, we don’t travel far enough in one day to make keeping the refrigerator on a necessity.
Be sure to double-check before leaving on a trip as state laws can change, but propane will likely not be allowed in the following areas:
- Maryland: No propane tanks in tunnels or the Francis Scott Key Bridge (the alternate route for RVs with propane is I-695).
- Massachusetts: No propane is allowed in tunnels (in Boston, I-90, I-93, Rt. 1A; in Newton, I-90).
- New Jersey: Open propane cylinders are not allowed while traveling on highways.
- New York: In Manhattan, No propane allowed in Holland Tunnel, Lower level George Washington Bridge (I-95 South), George Washington Bridge Expressway, Lower level Verrazano Narrows Bridge, Lincoln Tunnel, Holland Tunnel, and Lower level Verrazano Narrows Bridge.
- Texas: A maximum of two 30-pound tanks with the valve closed will be allowed in the Washburn tunnel (Pasadena).
- Virginia: A maximum of two approved propane gas tanks (20 pounds each). Tanks must be turned off when going through tunnels and Chesapeake Bay Bridge.
When traveling with the propane off, the appliances should also be turned off. Some appliances have an electric ignition that sparks to light the pilot light. This could potentially cause an explosion at a gas station. If you are parked at the back pump with your trailer or RV appliances away from any gas pumps, this probably isn’t an issue, but common sense should be used.
Do I Need to Turn Off Appliances When Refueling at a Gas Station?
Safety guidelines suggest that we “disable or turn off any auxiliary sources of ignition such as a camper or trailer heater, cooking units, or pilot lights.” What should you do if a fire occurs? “Leave the nozzle in the fill pipe and back away from the vehicle. Notify the station attendant immediately.”
While refrigerators are cited as the second highest cause of RV fires, it is usually due to poor wiring or a lack of maintenance (instead of stopping to refuel). Off-level operation is another cause. Annual maintenance and safety inspections are suggested.
UNIQUE QUALITIES OF A PROPANE FRIDGE
Effects of High Altitude on Propane Gas Refrigerators
When running the refrigerator on propane gas at altitudes higher than 5500 feet above sea level, you may experience reduced cooling performance and burner outages. To avoid this, Norcold recommends that you operate the refrigerator on AC when at high altitudes.
Effects of Freezing Temperatures on Gas Refrigerators
A gas absorption refrigerator is not designed to operate in freezing temperatures. If the refrigerator is not equipped for low-temperature operation, and if the cooling system of the refrigerator is exposed to temperatures of 32° F or lower for an extended period of time, the refrigerator may not operate properly but should resume when the cooling system of the refrigerator warms sufficiently. If the refrigerator is equipped for low-temperature operation, the refrigerator will operate in temperatures down to 0° F.
REFRIGERATOR CARE
Your refrigerator should remain trouble-free if you perform simple checks every three to six months:
- Make sure the airflow in the lower intake vent and upper exhaust vent is not blocked.
- Make sure the area behind the refrigerator is kept clear. Never use the area behind the refrigerator for storage (especially anything flammable).
Have an RV dealer or authorized service center do an annual safety and maintenance check.
Frost and Defrosting
Propane refrigerators are not frost-free. Frost may accumulate on the cooling fins under humid conditions or extended use.
The fins operate below freezing temperature and will form frost from the humidity in the air. Be sure to cool leftovers and to seal any moist foods or liquids before placing them in the refrigerator to keep the humidity down inside the fridge. Closing the door as quickly as possible each time it is opened will also help. (If heavy frost becomes an issue, make sure the seals on the door are still good and that air is not leaking into the fridge.) The temperature control system should prevent frost from building up on the cooling fins and the moisture should drain into a small tray underneath them.
When we get home, I simply turn off the refrigerator, empty it out, and leave the doors wide open. We put our dehumidifier back in right away and now have it placed on the kitchen counter with a drain tube emptying into the sink and gray tank. I do a quick sweep now (after filling our gray tank one-third full in a short time span) to make sure all the windows and vents are closed up tight too!
MAGNETS WON’T STICK?
Can panels be replaced with magnetic ones?
I giggled to myself a bit over this one because I don’t have many magnets on our home fridge — but in our travels, I’ve picked up a few souvenir magnets from places we really enjoyed. It hadn’t occurred to me that the outer fridge surface was also different from a home refrigerator. Yup. It’s just plastic. So I ended up putting magnets on the vent hood instead. It made me wonder. Could we replace the plastic inserts on the RV fridge with something magnetic?
It is possible to replace the panels, although I couldn’t find a product created specifically for that purpose. However, I explored a number of options:
- Galvanized Steel
Available in sheets or rolls and will cut to fit with tin snips. - Stainless Steel Backsplash Panels
Kitchen safe matches most #4 polished appliances and magnets will stick to it. This is the least cost-effective option but would look very nice. In most cases, the panels will need to be cut to fit. If you’re handy and want a top-notch result, this might work for you. - Umbra Bulletboard
A magnet board that also works as a bulletin board. Use both magnets and pushpins on it. Hang it on the wall instead of using the fridge. - Magnetic Board
A cheap an easy alternative to replacing the fridge panels. (Hang it on a wall instead. Use Command Hooks.)
MAKING IT WORK
Despite how different RV propane refrigerators are from the ones we use at home, with a few precautions and an understanding of their unique requirements, they are not difficult to use or maintain. They’re an efficient solution for any situation where electricity is not available.
Have any advice to add? Leave a comment below!
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