Propane smell inside unit

[gnijman]

I need help tracing the source of a propane smell inside my 2016 FC 25 FB Twins that I detected during the course of dewinterising the unit to get ready for our first Spring trip.

I am on Vancouver Island seaside so we have moderate temps over the winter. Except for all of February (which was all below zero) it did not freeze much. I blew out the air lines, drained everything, shut down the systems, plugged the unit into house power and plugged in a thermostat controlled oil-filled heater inside plus a small fan to move the air around. The temp was set at +10C (50F). I left the Use/Store switch by the door at Use.The propane was off at the two 30lb tanks. I checked inside the unit weekly and the temp was maintained as set.

I began my dewinterising with the propane system. I opened one propane tank. I started with the stovetop burners. I have only the stovetop as we opted for the Couture convection microwave instead of the propane oven.

The stovetop has three burners one front and two rear. I use a propane BBQ starter gizmo to ensure I have an ignition source when I open a burner valve, with the plan being to test the spark igniters later after all ignite property.

I started with the front burner. After opening the valve it took a few seconds for the propane to reach the stove from the tanks and then the front burner ignited. However, it was not the blue flame expected but instead it was a completely orange flame about two times larger than the blue flame ought to have been when lighting. I shut it down.

I knew from my propane stove in the house that when the diffuser a a burner is not properly seated or has junk in it that it gives off an orange flame so I was not then worried. I checked the two rear burners and they came on just fine.

I then took the front burner diffuser off (quarter turn then pull up). It looked like it was already seated but I thought it couldn’t hurt to take it off and put it back. I reinstalled it making sure it was seated well. I then tested the front burner again using the BBQ lighter.

This time there was a short delay before the propane ignited but the flame I got was more than anticipated. The burner ignited but I also got a stove wide puff of orange flame shooting out at me at crotch level. (Yes I know every male reader just cringed). I turned off the burner control and the flame died out right away. I’m not sure because it happened so fast but I had the sense that the “crotch flame” came out the air vents in the fascia that surround the convection microwave. It may have come out where the stove top meets the counter but that’s not what I sensed at the time.

After checking to make sure all was intact and after letting the stove top fittings cool I again took the front burner diffuser off. I thought that maybe there was a critter in the now exposed gas pipe so I put my lips on it and gently added air pressure and met resistance. Maybe there was supposed to be resistance at the valve - I don’t know. Anyway, I gave a light “puff” with my lips and felt the resistance clear. I reassembled the diffuser.

Standing slightly farther back I tried to ignite the front burner again and it lit and burned perfectly. I did not smell the “rotten egg smell” from the propane at anytime through all the above (in Canada propane is required by law to have an added odourant (I don’t know the situation in the USA).

Great, I thought and proceeded to test the fridge, furnace and HW heater on propane and all worked flawlessly without any residual propane smell.

I tested the heat pump and after it worked fine I quit intending to get the water systems going in a couple of days. I left the propane tank on. One roof vent was left open.

When I sent out to do the water sytems a few days later I smelled propane as soon as I entered the inside of the unit (no smell outside). It was not a heavy smell but it was present. I’m very sensitive to sulphur odor. I opened the door and blew the place out quickly with the Fantastic Fan and the range hood fan (not thinking at the time about possible electric sparks … duh). I turned the propane off at the tank.

After the smell cleared I tried igniting the front stove burner with the BBQ starter wand and there was residual pressure in the line and the burner ignited but burned out in a few seconds. I then tried to light the other two burners but no further propane was present in the lines.

I then closed up the unit leaving the roof vent open.

After an hour I went back out and upon entering I smell the same low level propane smell even though the tank valves were shut. I aired the unit out again, I unplugged the shore power, turned off the fridge and flipped the Use/Store switch to Store shutting down the 12v system. I closed it up leaving the roof vent open.

I let an hour pass and upon reentering I could detect the faint propane smell again.

Any ideas why I’m getting the propane smell in the unit?

Gary

[bweybright]

You show having a 2016 model, so was the propane sensor sounding? Or, did you disconnect it so it is not functioning?
I ask because if the sensor is not going off it could be other issues, like plumbing problems creating sewer gas?
Bob

[Gene]

I wonder why the propane alarm did not go off? Fortunately, you have a nose (yes, an odorant is added to US propane). Stuff is happening around the stove and microwave. The blast of fire in the microwave area tells me propane may be escaping a slight leak near that item.

I'd start there and remove whatever you have to remove to expose the propane piping and look for places to tighten the connections. On our trailer I found a few that had very slight leaks and tightened them. I also found the pipe to the pilot light was almost off making it difficult to light the pilot. So our experience tells me sometimes the propane system is not installed all that well (nobody want to hear that). Propane is heavier than air, so where you smell it strongest, the source is above that or very close or both. Turn off the propane when you search—sparks are always possible and you don't want another flame coming at any part. Once you tighten everything you can, then turn on the tank and go through the process of checking the system again while checking anywhere you have exposed.

Nanoose Bay is a nice place to live. We stayed in Nanaimo for five days because I got sick and while I didn't feel too well, it was a good place to recover from food poisoning.

[Green68]

Put one of these in your tool box. It works great but you have to be close to the leak so it can pinpoint the source.

https://www.homedepot.com/p/HOME-FLE...-001/301876827

[dbj216]

Hello from Colorado: From your description I would start hunting for the leak under the cooktop. You will need to gain access to the propane line from the floor up. Get a bottle of "leak detector" at the hardware store. You will have to brush it on every fitting and see if you can find bubbles forming. The cooktop itself may have developed a leak too, maybe in the piping, burner valves and the like. You can isolate the cooktop by disconnecting the flare fitting to it and then plug it.

Test with the door and windows open. Propane is heavier than air and will pool below the leak. The "crotch fire" may indicate the leak is in the cooktop and propane pooled on top of the microwave.

The US also has an odorant requirement for propane. I had a leak I smelled on the outside of the my trailer. I found it with leak detector solution at the pigtail connections to the pressure regulator at the front of the trailer.

Let us know when you find the cause.

David

[OTRA15]

Echoing questions about your propane detector . . . have you disabled it?

[xrvr]

Battery?

[n2916s]

Your nose is a LOT more sensitive than your propane detector. If you are awake, you will detect a propane leak way before any alarm is triggered. It is there to protect you while you sleep.

If you buy a plastic bottle of "bubble blowing" solution in the kid's department at the dollar store, it works great. A teaspoon if dishwashing liquid in a few ounces of water works well also.

Embarrassed to admit this but the last time we had that smell, it turned out to be a dead mouse disintegrating under the sofa... Bad smells tend to be similar...

[gnijman]

Thx for the suggestions and I will check into them all. No, I have not disabled any alarms and none sounded.

Gary

[SeaLevel]

The two times I have noticed that smell were both when the active propane tank was almost empty, as if some of the additive had settled to the bottom. After switching to the other tank the smell went away.

[rmkrum]

Sometimes the odorants really stink up the place, even when burning a stove burner. The amount varies, and it does accumulate a bit in lines and tank bottoms. It’s methyl mercaptan, one of the things that makes skunks smell bad. It’s oil based and rather persistent once in the piping. Since propane and natural gas have no odor, the gas industry uses this as a good way to detect leaks. Most people can detect it in very small concentrations.

Beats the alternative—undetected gas leaks are also known as fuel-air explosives!

[drbrick]

You will find several LP gas leak detectors listed on Amazon.ca

[gnijman]

Decaying critters or plant matter can’t be the issue, as some have helpfully suggested, because I was in the unit regularly all winter and the smell came on suddenly after the propane stove testing started. I did a thorough search anyway but found nada re dead critters.

I’m guessing my nose detects the smell before my propane alarm does and that could explain why it did not sound.

I’m still buffaloed as to why the smell returns with my propane tanks are turned off. Maybe my first check is to take off the lines at the tanks and see whether I smell anything right at the tank valve.

[gnijman]

Originally Posted by xrvr

Battery?

The batteries are the gel-type 6 volt ones in series. No smell there.

Gary

[Gene]

If the propane connections were done by the same guy and he didn't do as good a job as he should have, you could have more than one leak. I did. Anyway, if you smell propane outside and inside would indicate more than one leak.

If you turn off the propane, you may have trouble detecting a leak if the lines have cleared. But, of course, leaving the propane on can have very bad results. First I would tighten everything and you may find loose connections and never smell the odorant again. That would be a very good thing. The only reason I can think of for smelling the odorant when you turn off the tanks is that there is a leak at the tank valve which is activated by turning the knob. I can't see how you would smell anything inside when turning off the tanks. You can check this with two people. I notice that I smell the odorant when my wife does not—not everyone smells the same things when the quantity is small. Good luck.

[NY24]

Did anyone use any aerosol products inside the trailer recently? Many aerosols are propelled by propane gas. I've set off the propane alarm just by spraying aerosol foot powder into a shoe. Hairsprays are another item utilizing propane as the propellant. There are MANY other aerosol products that use propane as the propellant. Make sure to eliminate those sources before you go crazy trying to track down a suspected leak.

[Gene]

Wow! Propane as a propellant? Glad I don't use hair spray.

[n2916s]

Butane as well! The fuel of potato gun aficionados worldwide is hair spray!

On a more practical note -- the propane used to propel aerosol products has not been odorized, or your hair would smell like mercaptan...

[rmkrum]

Note that ‘dog farts’ will also set off propane detectors.

[gnijman]

Originally Posted by NY24

Did anyone use any aerosol products inside the trailer recently? Many aerosols are propelled by propane gas. I've set off the propane alarm just by spraying aerosol foot powder into a shoe. Hairsprays are another item utilizing propane as the propellant. There are MANY other aerosol products that use propane as the propellant. Make sure to eliminate those sources before you go crazy trying to track down a suspected leak.

Nope ... no aerosols. Good to have checked though.