What to do if your propane tank is overfilled

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By Heidi Bodette
LovingTheRVlife.com
Has your RV propane tank ever been overfilled? Well, it happened to us in January. Here’s what we learned so you can help ensure it doesn’t happen to you.

Warning signs
Looking back, there were warning signs that our propane tank was overfilled. First, when the man came to fill it, he mentioned he forgot to bring his glasses. Second, he had to change the hose adapter a couple times before he had the right one. Third, he didn’t open up the bleeder valve which is used during the refill process to alert when the tank is nearing the full mark (80%). And, last, when he released the connection, there was a stream of liquid propane that came out of the propane tank. Normally, there would be nothing or a momentary spurt.

When we left, we didn’t realize the tank was overfilled. Fortunately, while driving to our next location, it was cooler weather and the propane tank was in the shade at our new site.

What happens when your tank is overfilled?
When we arrived at our campsite, we turned the propane on and didn’t realize anything was wrong. In the evening, we turned on the furnaces as temperatures were going into the lower 40s. When we woke up, the RV was cold and the furnaces wouldn’t come on. Mark checked our propane stove and it came on but wasn’t acting normal so he shut it off. He checked the propane tank and the fill indicator was buried past the ‘full’ line! That isn’t supposed to be like that!

To allow for expansion, propane containers should be filled to only 80% of their capacity. The same amount of propane can take up more or less space depending on the temperature. The extra space in the tank is a cushion against pressure that builds up inside a tank when it is hot outside.

We found this on the Internet
“An overfilled propane tank can explode, causing damage and even injury. The risk of overfilling is complicated by the fact that the liquid in the tank will expand in warmer weather as pressure in the tank increases. The tank may also cause the relief valve to open and spill propane onto the ground.”

When an RV propane tank is filled correctly, it shouldn’t overfill because all tanks have safety devices to prevent this. But, because it actually did happen to us, this is what we did to fix it.

  1. First, we called Mark’s brother because he has a similar propane tank/setup. We also researched and connected with people in the Tiffin Motorhome Owners FaceBook group. This same situation had happened to a few others as well. Knowing our propane tank had a pressure relief valve to release excess pressure, we felt comfortable moving forward to resolve the situation on our own.
  2. Since propane is heavier than air, we made sure there were no ignition sources near the propane tank (open fire, someone smoking, etc.). We opened the bleeder valve slowly and shut it off again. When overfilled, you will get a SOLID stream of near-liquid propane. If the tank is at or below 80%, you get a mist of propane that is mostly vapor. When Mark checked the bleeder valve, it had a solid stream of liquid propane!
  3. We started the propane stove because it is less finicky when it comes to flow pressure. We turned all the stove burners on to burn off the gas. After 15 minutes, the stove burners returned to normal.
  4. Next, we turned on our propane furnaces and they started working immediately. We turned on the gas water heater and it worked correctly too. Then, we ran everything for quite a while to help reduce the propane in the tank. We continued to do this on/off the next few days. It turns out our propane tank holds 36 gallons.
  5. We continued to watch the propane indicator that showed that the level was going down on the tank and on our inside panel. It took about a week for it to get down to the 80 percent level.

Be informed and educated!
If this happens to you and you do not have confidence to proceed, we recommend you contact someone that does, i.e., mobile repair technician, RV dealer, or a reputable seller of propane.

This was quite the experience for us and we wanted to tell you how important it is to be educated and informed, especially with regards to propane.

Heidi Bodette and her husband, Mark, own and operate the fine blog Loving the RV Life. Sign up to learn about new posts from this interesting couple

##RVT936

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Al Kemp

My hat is off to you for starting the stove to burn off the excessive propane. I believe the damage done to our environment is less this way. We are all caretakers and must be as responsible as possible. Cracking the valve in an open area is even more work than doing what is right. The earth works hard enough.

Bob Palin

As I understand it portable propane tanks have an overfill prevention device, though expansion can negate its effectiveness. I’ve been traveling for 3 months now and have probably had my 7 gallon (30lb) tanks filled 20 times. I’m currently in New Mexico and they do things differently here, they never use the relief valve and they only ever put 6.4 gallons in the tank. In California, Utah, Nevada and Arizona they have always used the screwdriver in the relief valve and have always put 7 gallons in. The last time I filled was at a wholesaler because I needed to get my tank re-certified, the employee seemed knowledgeable and competent so I asked about the relief valve. She told me that in their training they were told it was only needed to bleed air from the cylinder, not when re-filling This experience with the different states has been confirmed by a friend who has been following a similar route.

Tommy Molnar

I can see if you’re in a campground or other crowded environment, reducing an overfilled tank might have issues. But the one time I found us ‘overfilled’ we were camping out in the Nevada desert. I disconnected the tank and removed it from our travel trailer, opened the valve and let some propane out, and life was good. I made sure we were not in the direction of the wind.
I used to deliver propane about 30 years ago and still retain ‘some’ 1075 knowledge. 🙂

Wolfe

Others noted this, but the advice in this article is a bit dangerous… Most tanks have OPD’s of some variety, but if needed, I myself would dare to flare off the extra propane through a remote hose, NOT inside the RV.

What did I just say? You SLOWLY run out the gas though something like a torch or torpedo heater MEANT to burn the gas. Remotely, so you don’t burn your house down.

Why burn it instead of venting? Because LP gas is an explosive you don’t want to make a big cloud of and accidentally ignite later or elsewhere… once burned, it’s inert.

If I really had to use the stove to do it, you hold the knob the entire time you’re doing it so you can shut off in under a 1/4 second if you get flaring liquid. But really, try not to.

Sally

a local filler at a convience store overfilled our tanks on numerous occations. they ruined our tanks. we bought new tanks with in tank gauges and stopped filling there. we moved to filling at a dedicated LP place that has certs for all their operators to fill during office hours never had that issue again. We dont use the trade out a tank services at places like circle k (we did that at times as well) either and we dont fill with just anyone anymore.

BILL

This article can easily get you hurt or killed dont ever ignite anything near an overfilled tank and/or propane system. Go to a reputable propane company or RV dealer and let a qualified technician evac your tank to a safe amount. If that tank was filled to capacity liquid could have been pushed into the regulator causing it to fail and sending tank pressure to the stove creating huge flames and lighting the RV on fire. This article is ill informed and dangerous.

Thomas

Nowhere in the story does it mention that the tank is in a motor home. Finally! a different animal than the tanks you take out and have refilled. ASME tanks do not need to have overfill protection. she/he should have said something when they saw he didn’t open the bleeder. Onus on them as much as the filler of the tank.

Billy Bob Thorton

One time while filling up at a U-Haul location, the young lady couldn’t even get the hose connection onto the fill valve. After fumbling with it, I knew my place, and politely asked to ” let me give it a try”. That went over like a lead ballon. She finally got it connected and began to fill the crap out of my onboard tank. I closely watched the onboard guage hit full, and she was oblivious. I yelled STOP. I’ve been around, so I no longer allow dumbness… to occur when i know a bad outcome will ensure. Boy, i sure felt bad for a second or two, then i thought, nope, not on my watch.

Dave

Every propane tank except 100# and above have OPD’s on them so it is impossible to overfill. On a motorhome they also have OPD’s on them making them impossible to overfill. If this person was having this much problem he wasn’t qualified to even pump propane. There are only two different kinds of connections, not three. If in a rare circumstance that the OPD is not working only then should you use the bleeder. Tanks other than on motorhomes are filled by weight and this is a law.

John M

I always watch as they fill my propane tank and if they don’t open the bleeder valve I remind them to do so. I also watch the needle on my tank as it fills to make sure it isn’t overfilled. Now days you have to watch what everyone does or do it your self. I let some one borrow my snowblower with a full tank of gas and when it came back the tank was empty. People don.t think nowdays like the older ones of us do.

Robert E Staples

Thanks very much for this article. From now on I will know what to watch for when my tank is being filled.

Dave W

One of ours was overfilled -1/2 pound IIRC. I installed it then immediately started the furnace and ran the HW heater Took less then an hour to bring the weight down to below correct fill poundage.

Jeff

I used to work for a FUEL Company, delivering Gasoline, Diesel and Propane!

In the State of Louisiana you must be certified to fill Propane Tanks. This is Not the case in many states and any boob can fill your tanks without any education on the Huge Dangers of working with Propane!

Amazing how things very from state to state!

Dale e Rose

In any instances of an overfill, it can be very dangerous to try burning off the excess propane as you did. Liquid propane expands 270 time it’s volume from liquid to vapor. Igniting the liquid at the stovetop can cause a huge flame. Go back to where you got the tank filled and they can pump some of the liquid back out. or any other propane company. The next safest thing to do would have been , if there is some breeze to disipate the gas and blow it away , would be to make sure that the area downwind is totally safe from a source if ignition, and guarded, let a little bit of the liquid out. Never get into an area of the vapor, because the gas will displace oxygen and kill you. And static electricity can cause a spark to cause an explosion. The gas can remain flammable for a great amount of time. I heard of propane following a ditch and being ignited 1 1/2 miles away, and running back to it’s origin, there was a big BOOM.