I recently installed a tankless hot water heater in my RV, but found a propane leak at the flare fitting that connects to the gas inlet valve on the water heater. I've tightened the fitting as much as possible without snapping it off but it still leaks. My question is can pipe dope or Teflon tape be used for propane connections? Any help would be appreciated.
Albert, (Rochester, NY)
Albert, (Rochester, NY)
Albert, no pipe dope or sealant of any type should be applied to a flare fitting. The 45-degree surface of the fitting mates with the inside of the flare nut, thereby “sandwiching” the copper tubing between them. This affects the positive seal between fitting and flare. If the fitting still leaks after tightening, I’d have to suspect the actual flare on the tubing as the culprit. Perhaps the end of the tube was not cut flush or the flare itself was incorrectly made. There is an outside chance that the fitting is damaged, but almost every instance of this type of leak are usually attributable to a faulty mechanical flare. If you have enough room, re-cut and re-flare the tubing properly using a true 45-degree flaring tool. If not, it may be necessary to go back to the next closest flare fitting and replace that entire length of copper tubing. I’ve included a diagram (above) that you may find helpful regarding copper flares.