Assessing RV Propane Tanks: ASME Tank Rundown

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Duration: 1:52

On most motor homes or RVs, the ASME tank or, in layman’s terms, the RV propane tank, is responsible for fueling a number of your vehicle’s most important appliances, including the oven, stovetop burners, water heater, furnace and refrigerator. Because propane gas is required to power so many of the components you use on a daily basis when you’re touring the country in your RV, it’s important to know at least a little bit about the makeup of and proper maintenance procedures required for a standard RV propane tank in an ASME system.

To help you get to know your RV propane tank, Dave Solberg pulls back the cover on his demo vehicle’s ASME tank and discusses some expert tips for maintenance and filling that will apply to any model. He highlights a few of the important aspects of the typical RV propane tank that you should consider when taking it to your nearest certified fill station for safe filling and when monitoring it while out on the road.

What to consider when filling your RV propane tank

Dave begins the fill and maintenance process by walking you through the components on the outside of the tank, which can usually be found permanently mounted on the passenger side of your vehicle. Follow each step of the process and you’ll ensure your tank lasts forever!

One thing you should pay attention to on your RV propane tank is the proper fill level. Due to the fact that propane expands at hotter temperatures once inside the tank, OPD valves on ASME tanks only allow you to fill up to 80 percent of the total provided capacity. Tanks should only be filled by professional technicians at certified stations, where they are filled by the gallon since the tank cannot be removed to weigh it.

It’s important to note that while they are filled by the gallon, propane tanks are designated by pounds. However, trailer-mounted propane tanks are typically removed and filled by pounds as they are weighed on a scale. Propane weighs 4.2 lbs per gallon, thus an 80lb ASME tank on a motorhome could hold up to 19 gallons, however the OPD valve limits it to 80 percent, which would be approximately 15 gallons.

Additionally, users should make a note of the fact that RV propane tank covers and doors do not have locks in the event of an emergency. Located on the passenger side of the vehicle and permanently mounted to the frame of the RV, you don’t want to have to fiddle around with keys in response to a time-sensitive issue. If you have any questions about your particular model, be sure to refer to the user manual or an expert at your fill station.

Other things to keep in mind

In addition to fill limits, Dave introduces a few other aspects of ASME tank maintenance that you should consider. He teaches you the proper way to utilize the propane tank monitor on the inside of your vehicle, which allows you to keep an eye on your fill level.

Furthermore, he explains why it’s so important to turn off all pilot lights for appliances such as refrigerators, furnaces and water heaters when taking your vehicle to a certified fill station. A certified technician will almost certainly check to see you’ve done so prior to filling your tank, but it’s always recommended that you take care of this step prior to heading for the station.

And that should just about do it! Remember Dave’s expert advice for maintaining your RV’s ASME tank, and you’ll guarantee that your propane is in proper working order and you won’t run into any issues when you least expect it!

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14 Responses to “Assessing RV Propane Tanks: ASME Tank Rundown”

  1. ashley

    I just bought a 2007 aljo limited and I was wondering how to light the pilot for the hot water heater??

    • Customer Service

      Hi Ashley. It really depends on what type and manufacture of the water heater you have. Most water heaters have direct spark ignition and it just requires you to turn on a switch on the inside of the coach for it to ignite. Most of the time these switches are illuminated as well. If it doesn’t turn on you want to first check the fuses. You then want to check the water heater and listen for a clicking nosie. If there is no click then the control board is not getting voltage or has an issue. If it does click but doesn’t ignite then there could be a gas flow issue, gas valve, blockage in the burner or something else. There are also pilot models, these are more common on older units and smaller ones but you could still have it. If a pilot model you will have to access the outside of the water heater and check the gas valve. There will be a control in the “off” position. Turn it to “pilot” and press it down while holding a flame to the end of the burner. Once the pilot lights you can then turn the button to the “on” position and it should ignite. If the pilot will not ignite then again there could be a blockage in the orifice, burner, bad gas flow or the valve is bad itself. We do have some great water heater troubleshooting videos that could help you as well.
      RV Repair Club

  2. Karen

    We smell propane, furnace won’t light, alarm sounds when try to start generator?
    RV service not available until July 2, any ideas? Thank you, Karen

    • Customer Service

      Hello Karen!

      That’s a great question!

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  3. Bette

    Does anyone know if replacement propane tanks are available for 1996 Roadtrek Popular, and if so where? Ours is leaking. Thank you.

    • Customer Service


      Those should be available aftermarket. You will want to search for the gallon size. There should be a data tag on the tank you have now that will have this information as well as the dimensions. Once you find the gallon size you can then compare and find one with the same measurements. I know Flame King makes many sizes and Worthington Industries make many as well. I will post a link to their website with more information. I hope this helps!


      RV Repair Club Technical Expert

  4. Dale

    My sister and husband were traveling yesterday when the pressure relief valve started leaking on the propane tank in their 1997 class c motorhome. The service center they went to for help insisted that the tank is too old to be fixed. They told them that ALL RV tanks are REQUIRED to be changed every 10 years. Their motorhome is a 1997, always stored inside, and there is surface rust on the tank. But it is the relief valve leaking. They service center is replacing the tank and all the gas lines and fittings because it has to be done every 10 years and they insist it is illegal for the just the valve to be replaced. My sister asked them just to remove the tank then and cap the lines. They refused to do so also saying it would be illegal to do also. If the tank is removed, it must be replaced with a new one. Thoughts?

    • Customer Service

      Hello Dale,

      We just finished shooting a video on proper DOT Cylinder and ASME tank filling, storing, and certification. DOT cylinders which are the smaller upright models are required to be recertified every 12 years, not replaced. And, according to our certified propane distributor, the ASME tank on all motorhomes are not required to be certified or changed, rather inspected and can have a pressure valve replaced. However what I have found with several service locations whether it’s propane or other types of service, is that we are subject to the individuals “interpretation” of the rules which are not always correct! I would find another “certified” propane distributor that is familiar with RVs as I believe this location is interpreting the situation incorrectly? Make sure it is actually the pressure relief valve which is typically located on the bottom of the tank, and not the outage valve which is the small threaded cap that is open to allow air to escape during filling?

      David RVRC Video Membership

      We’d love to have you be a part of our community. We are convinced you will enjoy the benefits of becoming a member and having access to the best instructional how to videos and professional tips. We would like to offer you a special promotion for your first year membership.

  5. William Cronenwett

    Your video was OK, I would change it to show the FILLER Valve, Fixed liquid level gauge, relief
    valve, and then the site gauge. Explain that The Fixed liquid level gauge is required to be open while filling to prevent overfilling the tank. Relying on the site gauge or the filler valve IS NOT CORRECT. A few of the filler valves have failed in the past. Another comment is that Motor fuel tanks (Motorhome tanks) are not required to be inspected prior to filling. A good thing to know is the letters W.C. which stands for WATER CAPACITY, which is the capacity of the tank IN GALLONS. The maximum the tank should be filled is to 80% of the W.C. (I.E. 100 Gal. Tank @80% = 80 gallons propane. One last comment, some older tanks might not have the 80% shut feature, That is why you use the fixed liquid level gauge.

    • Customer Service

      Hello William,

      We appreciate your feedback and it has been forwarded to the proper department. Your comments are important to us and help with the development of new programs and offers. We will continue to listen and work hard for your complete satisfaction.

      Becky RVRC Video Membership

  6. paul

    Are motor homes allowed in tunnels that have a 20# tank at the entrance in with the restrictions?

    • Customer Service

      Hi Paul. Thanks for visiting the RV Repair Club site and the opportunity to assist with your propane/tunnel question. There is not a nation wide ruling on propane tanks in tunnels, rather every tunnel has it’s own restrictions. I personally have run into two situations, the Lincoln Tunnel in NY, and one in Boston. Both did not care about the size and even if the tank was empty, no entry! Most of the GPS monitors now have a listing for restrictions, however stop in to any Pilot, Flying J, or Bosselmans truck stop and get the truckers atlas and most of the restrictions are listed there.

  7. Norma

    We always level our motor home when using it but are you saying that we also need to be sure it is level when we store our motor home until the next time we use use it?

    • Customer Service Techs

      Hi Norma. Thanks for visiting the RV Repair Club site. You only need to have the unit level when running the refrigerator as the coolant inside the cooling unit needs to make it’s way back to the bottom via gravity. If you are storing the unit and the refrigerator is off, it doesn’t matter.

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