Very slow propane leak: how to find it?

LadyRVer wrote:
I had a LP leak, could smell it at times... turned out to be the gas valve in the water heater. When I shut the hot water heater off, the flame would not go out.
I was told by a few "just blow the flame out." No way. Just a thought. The intermitten LP smell was very hard to find. In my thoughts, LP problems need a professional to fix them. Costly, but safe.

This is very common on older Atwood DSI Water heaters. BUT, the leak is not going to be more than a few ounces a day. Odds are, it is one of your HI pressure Pigtails at the tank. With both Tanks on, twist and wiggle those hoses where they are crimped. Odds are if you have soapy water on those fittings you will see the leak. 1/4 of a gallon a day usually means a HIGH pressure side leak. If it was low pressure, you would smell it in the RV very easily. If the Pigtail leaks replace BOTH. Doug

I had a LP leak, could smell it at times... turned out to be the gas valve in the water heater. When I shut the hot water heater off, the flame would not go out.
I was told by a few "just blow the flame out." No way. Just a thought. The intermitten LP smell was very hard to find. In my thoughts, LP problems need a professional to fix them. Costly, but safe.

Dan,

I had the same situation going on in our Class C for years after we had bought it new! Except probably my leak was less than yours, so our RV was usable other than for our propane use seeming to be a bit too much week after week from an 18 gallon tank.

I didn't feel there was any safety issue because the leak could only be smelled when outside, in the immediate vicinity of the tank.

I finally had it thoroughly looked into by a competent RV repair shop last year: The small leak was from the threads in the steel sleeve where the brass fill valve was screwed into the steel tank. The shop said that probably the threads in the tank had been slightly stripped during robotic machine assembly of the tank.

I had a new tank installed and the technician said that indeed the tank threads were dinged up. Now finally, we have no smell outside and a longer lasting propane supply.

Any propane leak into, or originating within, the interior of the RV is of course a different and dangerous situation. Keep after it till it's fixed!!

Like working on a car, start replacing the cheap things and work up to expensive thing.
Your rig is a 2012? ot that old, but could be regulator, esp since u dont smell the propane in the RV. You will not get soapy bubbles if the diaphragm is leaking out since it does not have a surface u can test. Replace it as it is 6 yrs old, so not a big loss $40 - $60.
Next thing is the valves on appliances - furnace, h2O heater etc. But you would smell propane inside probably with furnace, maybe not with water heater; another $40-$100 for the valve and maybe or maybe not replaceable.
Before replacing those get a plug and unhook furnace from gas supply and see what happens, or not. Then to the next appliance. If it is one of those valves or something on the appliance, then disconnecting it from gas will solve the problem. I currently have my furnace disconnected and waiting for a new valve.
Hope that your copper supply line is not cracked. You would either see something rubbing on it or it have a bad kink to have a leak usually. unlikely, but possible.
A stove or oven leak you would likely smell inside, I would save that for last.

If you are near a HVAC supply store get a bottle of Big Blue .it reacts to refrigerant & propane so you get a foaming area at the leak.
I. Just had to replace a leaking regulator, leaking around the seam where the halves are pressed together.

Even where the propane line attaches to the tank. It could be anywhere!

When I have a leak I take the rig to the commercial propane dealer that I normally use to fill the tank. They find/fix the leak very quickly and never charge me.

Soapy water over EVERY INCH of your propane lines.

If you cant find any leaks then you might have to plug the gas lines to stove, Water Heater, furnace(s), absorption fridge and such then pressure test the lines. If they are gas tight then it must be one of the appliances.
Don't forget the pressure regulator, they can sometimes leak as well as any rubber gas lines, e.g. lines from regulator to tanks and rubber gas hoses if you have a gas appliance in a slide.
Not fun but the only way your going to track down a leak.

I had a similar issue. Took months to find it. Many friends told me it's probably the regulator or the supply hoses.

Did soapy water over and over. Finally found it. It was a leaking hose where the metal on metal swivel happens.

I think someone here said to wd40 that connection as part of normal maintenance.

Can you take it to a propane dealer? They may have more sensitive equipment. Or, an RV dealer that does RV systems inspections? Or, look in the Yellow Pages for mobile RV repair near you.
I doubt anyone on an internet chat forum will be able to find your leak. You'll get a lot of guesses, and maybe similar suggestions to take it to a pro. I would start by shutting off the main valve until you decide what you're going to do.