A Beginner’s Guide To An RV’s Propane System
In an RV, propane is often used for operating the refrigerator, furnace, water heater, and stove or grill. The propane is stored in a high-pressure tank and is distributed to the various appliances through hoses where it is burned to produce heat at the appliance. Propane is either the primary power source such as the stove or grill or is an alternate power source such as the fridge or some furnaces and hot water tanks.
Propane is considered clean, affordable, and reliable that’s readily available almost everywhere. Before solar power systems became available, a lot of propane-powered appliances were created and are still being used to support the RV lifestyle. It’s the most cost-efficient and still the best power source for everyday appliance use in your rig.
Propane (C₃H₈), also known as liquified petroleum gas, LP gas, or LPG, is a flammable, colorless, odorless, and non-toxic gas that has an odor added to it to be detected. It normally stays in gas form at standard pressure, but to make it easier to transport, it will be compressed for it to turn into a liquid. It’s available as natural gas and is also a by-product when petroleum is made into gasoline.
Where Is The Propane Stored In An RV?
Propane used in RVs is stored in specific propane tanks/cylinders. There are three (3) different types of pressurized propane tanks that are certified/approved to follow national and local regulations. As explained by the Propane Education & Research Council, the types of tanks are ASME stationary containers, DOT containers, disposable containers.
- American Society of Mechanical Engineers (ASME)-certified cylinders. These tanks are usually large (20, 30, 40, 60, 80, 100lb) and installed horizontally in homes and RVs. These tanks are typically built-in into the driver’s side of the RV. The compartment door isn’t locked for easy access during emergencies, it will be the only on that is not locked.
This tank type comes with its own set of gauges/valves:
- Fill valve
- Outage valve
- OPD valve
- Vapor service valve
- 2-stage regulator
- Department of Transportation (DOT)/Transport Canada (TC)-certified cylinders are also called stationary or exchange service cylinders. They stand upright and are smaller than ASME tanks (20, 30, 40 lbs) due to the hitch weight limit. It can be readily brought to a service center to be refilled/exchanged. These tanks are usually mounted & covered in the rear side of the travel trailers, campers, 5th wheels, etc.
- Disposable cylinders. These are often 1lb propane tanks intended for camping (e.g. propane grill/stove) or soldering. They’re generally intended to be disposable, although there are some approved/licensed tanks that can be refilled.
The main difference between motorized and towed RV propane systems will be, (1) the type of propane tanks used, (2) how these tanks are mounted to the motorhome, and (3) the connectors needed [not including the different propane-appliances].
Do Propane Tanks Expire?
What is the lifespan of a propane tank? The lifespan of a propane tank is dependent on the type of cylinder it is. ASME tanks do not have a fixed expiry date or recertification date. DOT tanks need to be recertified every 10 to 12 years or is recycled. We reached out to Manchester tank, a large manufacture of all types of tanks including RV propane tanks. They informed us that ASME tanks do not have a specific expiry or recertification period. If the ASME tank has not been damaged, then they will last a long time without compromised integrity of the tank.
Fixed location (RV or home)
20 lbs – 100 lbs
Trailers, campers, BBQ
5 lbs to 100
10 – 12 years
BBQ’s, camping stoves, buddy heaters
One time use and is disposed
How To Identify The Different Types of Propane Tanks
There are three types of tanks used in camping and RV’s, the easiest way to identify each is by the size and portability. If the tank is 1lb it is most likely a one-time-use disposable. If the tank can be carried by hand and has one nozzle for the propane to go in and out of it’s a DOT cylinder. If the tank has a yellow fill nozzle, gauge, a service and shut off valve and a relief valve it’s an ASME tank. ASME Tanks are typically fixed to the RV. DOT tanks are portable. be sure to look for a label on the tank it will tell you if it is a DOT or ASME tank. The DOT tank will have an expiry date
In most motorhomes (Class A, B, C), the propane tank is usually mounted to the driver’s side of the RV. The propane tank size will differ based on the size of the RV.
The flow of propane goes from:
ASME propane tank (OPD valve) > POL-1/4” NPT Adapter > (Optional Propane Tee) > regulator > Supply hose > gas piping > propane-appliance(s)
On the other hand, the flow of propane in a towed RV (trailer, camper, etc.) goes:
DOT propane tank (OPD valve) > (Optional Propane Tee) > RV pigtail hose > regulator > Supply hose > gas piping è propane-appliance(s)
What Are The Parts Of A RV Propane System?
In general, the RV propane system starts with propane leaving the cylinder, goes through the appropriate adapters/connectors, then regulator, then through the hose/pipes, and ends as it enters propane-appliances.
- Propane Tank Cover
- Propane Tank Holder
- Propane fuel gauge (ASME, but some DOT tanks will have it)
- Automatic switch over to switch tanks
- Weighing scale (optional)
- Expiry cover
- POL-1/4” NPT Adapter (ASME tanks only)
- Propane tee (optional)
- Pigtail-hose (DOT tanks only)
- Supply hose
- Propane Lines
- End Appliances (as applicable):
- Water heater
- Propane grill
Refilling Your Propane Tanks?
Propane tanks can be refilled at travel and truck stops (Flying J and Love’s, U-haul, etc.) or certified distributors. Websites like U-haul, Amerigas, the US Department of Energy AFDC, and other companies can help find the nearest propane refilling station in North America.
To know if you still have propane inside the tank, one can check the gauge on an ASME tank. For DOT tanks, only some of the newer ones come with a gauge or an aftermarket one can be purchased for it. Another way to check if you need to refill is to use the “warm water, cool hand method” – pour warm water over the side of the DOT tank, and feel along with the cylinder.
Once it feels cool to touch, that’s where the propane level is. Another way is to also use analog tank scales or a wireless smart tank meter. Unless you’re familiar with the weight of the tank, some RVers can gauge (from experience) the weight just by lifting the tank itself.
Note that dealers won’t refill the tank if the DOT tank certification has expired. Depending on the country you’re in, these propane tank certifications are good for the first 10-12 years. The cylinders then have to be recertified or exchanged/purchased at your local dealer.
How Long Does A Full Tank Of Propane Last?
How long your propane tank will last will depend on different factors:
- number of appliances
- type of appliances
- size of appliances
- weather conditions
The propane-fueled appliance usually has its BTU rating indicated. Since one (1) gallon of propane has around 92,000 BTU, you can compute how much propane you have in the tank, and how much each appliance will consume if it’s running. Trying a fuel consumption calculator can help with this task.
Weather also plays a factor. For example, since a furnace (30,000 BTU) doesn’t run continuously (it will switch on/off to maintain the desired temperature), one (1) gallon of propane can last 4.5 days (or 3 hours if it runs continuously off a 20lb tank). Below is a summary table based on averages.
Propane Tank Size
|20 lbs||30 lbs||40 lbs||100 lbs|
|Capacity||4.5 – 4.7 gal||7 gal||9.4 gal||23.6 – 25 gal|
|Tank Weight (full)||37 lbs||55 lbs||72 lbs||170 lbs|
|21.59 hrs||84 hrs|
Safety & Maintenance With Propane
Propane Safety and maintenance are key to preventing inconveniences and accidents while camping. A summary from the US Propane Education & Research Council guidelines are listed below:
BEFORE A TRIP
- Always get to know your RV, your RV propane system and read the owner’s manual. Understand what gauges/valves need to be turned off during an emergency (leaks, etc.)
- Plan ahead. Find closest propane refilling station and technician in the area or contact camp site beforehand
- Have a Class BC fire extinguisher
- Install propane, carbon monoxide, and smoke detectors.
DURING THE TRIP
- Ventilation. When using any propane device, make sure there’s ample air circulation (open a window/exhaust fan).
- Use appliances for their intended purpose. If during winter, there isn’t enough heat, don’t use stove, propane grill, buddy heaters (can be dangerous), as a heat source or flammables to support the furnace. Use Electric heaters instead powered by shore power or an external portable generator.
- Propane tanks should be at least 10ft away from flame/heat source (grill, stove, etc.)
AFTER A TRIP
- Always make sure to switch off all propane appliances before touching the propane tank
- Switch off all valves and gauges
- When storing DOT tanks, store them upright in a separate, well-ventilated area. Protecting it from heat, rain (to prevent rust), or snow.
- Winterizing tips can be found in HERE
Annual maintenance system checks are important. Making a list of all the RV propane system parts (tank, hoses, regulator, etc.) and their manufacturer warranties will be helpful during the system check. Always include safety devices (smoke detectors, fire extinguishers, etc.) as part of the annual check-up.
If the RV was purchased second-hand, it’s very important to know all modifications done to the propane system.
For troubleshooting tips see the RV Propane Troubleshooting Guide, Hose and Regulator Replacement, and Installing or Replacing Propane Appliances articles.