Having hot water, a stove that works, and heat when the temperature goes down is great. For RVers, propane makes all these good things possible. Do you have a travel trailer or fifth wheel? Then your propane (or LP, for “liquid petroleum”) is kept safely stored under high pressure in LP cylinders—most likely two of them. That storage pressure has to be reduced to a much lower level, and that job is done by a propane regulator. It’s a low-maintenance item, but it does require your attention.
Sight-glass indicator tells all
Most “towable” RVs have two removable LP cylinders. When one empties out, an automatic change-over regulator will simply start drawing on the other cylinder. An indicator in the regulator’s sight-glass will show you that you have an empty cylinder and it’s time for a refill. With this kind of regulator, you can take the empty away, leaving the other hooked up, keeping stuff like the refrigerator operating. No need to move the RV to refuel the propane.
How does the indicator work? While your regulator may look different, automatic changeover regulators are basically the same. Notice at the top of the photo there’s a small cylindrically shaped item. That’s the sight-glass—you’ll see it has a strip of green in it. Below it is a large knob with a “pointer” pointing to the left. That’s the cylinder selector lever. The sight-glass indicator is keyed to whichever cylinder the lever points to. In this case, the sight-glass, showing a green flag, indicates the left cylinder still has gas in it. If the indicator were red, it would mean that cylinder is empty. Some older regulators may use a silver-colored flag to indicate gas, with a red flag indicating empty.
Change out that empty!
Here’s how to change out an empty cylinder. When the sight-glass indicator shows you have an empty, TURN the lever (or the pointer knob) of the regulator toward the “full” bottle. Then TURN OFF the empty container supply valve, turning it completely clockwise. Now you can safely remove the empty container by disconnecting the rubber “pigtail” or connector hose. Twist the plastic connector at the bottle end of the pigtail counterclockwise.
When you bring the refilled cylinder back, slip it into place, connect up the pigtail, turning it clockwise. What we do now is flip the selector lever and point it to the “fresh” cylinder. What will happen is that if an appliance is drawing LP, the indicator flag will turn red. We then open the supply valve on the top of the cylinder, SLOWLY. At first just barely “crack open” the valve, then go ahead and open it the rest of the way. In some cases if you just blast open the cylinder valve, a safety device inside the pigtail will shut down the flow. The indicator flag should now turn green. That means you didn’t accidentally kick-in that pigtail safety, and gas is flowing from the newly refilled cylinder.
What if the indicator still shows red? First, make sure there is a demand for gas. Light a burner on your range. Now check the flag. If it’s still red, you’ve likely triggered the pigtail safety. Close the valve on the refilled cylinder and disconnect its pigtail. That should allow the safety to reset. Reconnect the pigtail and repeat, opening the cylinder valve slowly. Once you’ve assured yourself that you have gas flow from the “fresh” cylinder, be sure to flip the tank selector lever back to the other cylinder.
A regulator will tell you if you’ve sprung a leak
Automatic changeover regulators are not only useful in keeping you in gas, they can also tell you if there’s a leak in your RV propane system. With all propane appliances in the RV turned off and no pilot lights left lit (or turned on), turn off the gas valves on your propane containers. At this point, the regulator sight-glass flag should show “full.” Keep an eye on it and within a few minutes (or even a few hours) if the sight-glass flag shows “empty,” it’s a safe bet there’s an LP leak somewhere in your system. Have your system checked immediately!
LP regulators don’t require a lot of attention. You need to keep safety first. Your regulator has a vent, and it will be clearly marked as such, as you can see from the picture. The vent must always be pointed DOWN. Vents are equipped with a screen-like material to keep dirt and bugs out. Keep the screen clear to allow the regulator to breathe, and in case of malfunction, to blow off excess pressure. Keep water out of the vent by keeping the regulator covered and out of the elements. Notice the indicator flag on this regulator isn’t at the top, but in the middle.
Happily, regulators are happy creatures. Keep the vents clear, and know how to change out empty cylinders and life will be good.
Updates: 09/19/2022 4:57 PM. Corrected error on which end of the hose to twist the connector.