By Russ and Tiña De Maris
Are these fittings safe? Like a lot of other areas in RVing, there are at least two viewpoints. Certified for LP use, quick-disconnect fittings are generally considered safe for use. But … there’s always a “BUT” involved. There are different ratings on quick disconnects. A low pressure, commonly a 1/2 psi-rated fitting, surely doesn’t sound very “high pressure” rated to the ear. In practice, however, 1/2 psi is more than the pressure delivered by your rig’s pressure regulator to appliances. Here’s the lowdown: An RV propane regulator should be set to deliver 11 water-column inches (WCI) of pressure to your appliances. The formula to jump from WCI to PSI (pounds per square inch) is WCI/27.68=PSI. My calculator says that works out to less than 0.4 psi, well within the safety range of a low-pressure quick disconnect.
That of course, assumes you’ll be running your heater on the low-pressure lines running through your RV. There is one area where you could get yourself in trouble. The Mr. Heater line of blue flame-style heaters designed to be run on small throwaway propane cylinders has a provision where you can run off a big LP tank. However, the regulator for the Mr. Heater is built into the heater – you would need to run unregulated pressure into your Mr. Heater unit. This is a far higher pressure and definitely out of the safety ability of the low-pressure quick disconnects. Quick disconnect fittings for gas use should have their operating range stamped on them; Look for it when you shop.
We have a friend who runs a blue flame-style heater in his motorhome. For years he has used a quick disconnect purchased at the hardware store, not designed for gas, but simply for use in workshop air lines – the same sort of quick disconnect you’d use to couple your air compressor hoses together with. He swears it works well and saves him a lot of money and, to date, he has not blown his rig up. But our experience with air compressor hardware like this suggests at times those things really can leak. We’re not willing to risk our lives for the cost savings of a few bucks. Here’s one designed for LP or natural gas you can pick up on Amazon.