Answers to questions about RV Repair and Maintenance from RV expert Dave Solberg, author of the “RV Handbook” and the managing editor of the RV Repair Club. This column appears Monday through Saturday in the RV Travel and RV Daily Tips newsletters. (Sign up for an email reminder for each new issue if you do not already receive one.) Today Dave discusses driving with the propane refrigerator on.
Half of the RV community says it’s okay to run an absorption fridge while traveling (except through tunnels, and when refueling). The other half of the RV community says no. The manufacturer says you have to be within xx amount of degrees from level, front to back and side to side, to prevent damage.
My question is: While traveling the roadways up and down hills, with an absorption fridge running and the possibility of wind blowing the flame out, what damage can be expected or done to the fridge with it on? —John
There is a big difference between legal and safe when it comes to several aspects of RVing, I have found. In the 1980s and even early ’90s there were about 12 states that outlawed the use of any propane device running while driving down the road. However, since there are now several vehicles that run on alternative fuels, one of them being LP, there are no states that I know of that restrict it. But, yes, there are certain areas such as many tunnels, the Washington Bridge and other areas that restrict passage, as well as when refueling.
It’s best to shut propane off
In my opinion, it is best to shut the propane tank or cylinder off at the valve when driving down the road. I helped develop the RV Safety & Education Foundation’s Safety Program, and one of the topics was propane safety. We researched information obtained from the cylinder and tank manufacturers, valve manufacturers, propane suppliers, and even state and federal law enforcement and emergency responders. The general consensus was to shut the valve off. The reason is not for the damage it could possibly cause the refrigerator, but the potential for an LP leak and fire or explosion!
How an absorption refrigerator works
Let’s look first at your comment about damage that could be expected or done to the fridge. An absorption refrigerator has a liquid vessel that contains ammonia, hydrogen, water, and sodium chromate. A heat source such as a flame in the case of the LP mode or heating element in the 120-volt AC or 12-volt DC mode heats the liquid until it turns into a vapor and travels up the tube to the evaporator coil in the freezer section.
The vapors and liquids do a series of chemical changes and flashes that I won’t bore you with. Then they all need to make it back down to the bottom of the refrigerator, by gravity, through a series of zigzag tubes in the coiling unit to start the process again.
Both Norcold and Dometic state the unit should be level at certain degrees front to back and side to side for the liquid to flow, as there are no pumps to assist. If the unit is out of level, the fluid can pool in one of the curves and will heat up and start to flake and eventually harden, blocking the flow of the liquid before it can get back down to the burner vessel. It will ultimately ruin the cooling unit. This is only while being stationary, as it takes several hours or even days for the liquid to start to flake and cause damage. Typically, driving conditions will move the unit around enough to allow the liquid to go back down.
Why the open flame could be dangerous
The real issue is having an open propane source and the potential for leaks, accidents, and a flame from the refrigerator or other propane-fueled appliance that could ignite that fuel source. The propane lines in most RV’s are ¼” copper and can oftentimes run under cabinets very close to the sidewall of the rig. If an owner gets too close to road signs or construction equipment and “clips” the sidewall, it could rupture the line and create an LP leak inside the rig. Then you have the refrigerator with an open flame in the burner assembly that could ignite the entire coach.
Bumpy roads could cause problems
Hopefully, you will not have an issue with construction, signs, or other obstruction that can cause damage while driving and rupture a line. However, you could have a connection that can cause a leak at an appliance as you are taking a unit down the road at 65-75 mph on some of the best washboard roads in the country.
So how do I keep my refrigerator cool while traveling? We conducted several tests on both Norcold and Dometic units and bringing the unit down to an operating temperature of 36 degrees and shutting it off, they maintained a temperature of approximately 40 degrees after 6 hours.
Note: If you do choose to run the refrigerator on the propane mode while traveling, you must shut off all LP appliances that have an open flame when entering a fueling station.
Read more from Dave here.
Dave Solberg worked at Winnebago for 15 years developing the dealer training program, as marketing manager, and conducting shows. As the owner of Passport Media Creations, Dave has developed several RV dealer training programs, the RV Safety Training program for The Recreation Vehicle Safety and Education Foundation, and the accredited RV Driving Safety program being conducted at rallies and shows around the country. Dave is a leading expert in the RV industry and author of the “RV Handbook” as well as the Managing Editor of the RV Repair Club.
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