RJ's Guide to RV Propane Systems
RV Propane Systems
Propane is an efficient way to power many systems in your RV, such as the furnace, oven, stove, and absorption refrigerator. If you have a tanked water heater, you may be able to use electricity and/or propane. Knowing which appliances run on propane and knowing what to expect during different altitudes and weather conditions can help improve your camping experience.
Let's have a look at some of the features of a propane system. Let's suppose you only use your water heater, oven, and refrigerator with a 30-pound tank. The colder it gets, the less pressure the tanks generate and the more demanding it is to operate your appliances; they need that pressure in the lines to run properly. So, keep this in mind when the winter months approach: you'll use more propane than you would during the summer, even if your furnace wasn't turned on. By keeping your tanks warmer, you will be able to produce more. Propane tank warmers are available so if you frequently find yourself in cold weather conditions, they are worth the investment.
Now let's talk about when you're at higher elevations such as 7,000 to 8,000 feet above sea level. The higher in elevation we get the thinner the air is around us. This could havoc on some of the propane-powered appliances. I would strongly recommend if you're at 8,000 feet above sea level or more to run your RV refrigerator off of electricity if you're interested in keeping your food cold.
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Propane Lockout
When you're swapping out propane tanks, there's a chance that the system will shut down if you are attempting to also run one of your gas-powered appliances by accident. There is a safety valve in place that detects when the system has high pressure on one side of the valve and very low pressure on the other. Here's what you need to do to fix it. Start by shutting off your propane tank and waiting a few seconds. This allows for the reduction of high pressure on the valve, allowing it slowly to open back up. You should hear a ting sound as the valve opens back up, and you should be good to go after that
Here's a tip. Before installing a new tank, make sure all of your appliances are turned off. Don't forget to turn off the furnace, if you have your thermostat set to HEAT it could start to cycle when you're in the middle of replacing a tank.
Propane Auto Regulator
For RVers with a split cylinder system, there is almost certainly an automatic change-over regulator. You should be able to see a dial on the regulator that allows you to choose which tank it draws from. If you have it on the off-door side, it will draw from that tank first and the indication will be green if it is full. The indication will change from green to red when the tank runs out. At this point, you may flit the dial to the other tank and feed off of it. I recommend checking this device weekly to ensure that you still have a green indicator.
You may also have an easy connection to your propane system for an outside grill or fire pit. It should be on the RV's door side. To connect, you'll need a male quick connect fitting on your grill. To join these fittings, first turn off the gas shutoff valve just at the fitting and then push the collar back while pushing the male fitting into the female portion. Then release the collar to secure the fittings in place. Then switch on the propane valve and you're ready to go!
Auto-Changeover Regulator
Propane Safety
A few key things to remember about propane gas:
- Propane is heavier than air and will settle at the lowest possible level.
- Always store your propane in a well ventilated area away from any heat sources.
- If you suspect a leak, use soapy water in a spray bottle to check for leaks.
- If you smell gas, open all windows and doors and leave the area immediately: DO NOT IGNITE ANYTHING!
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Propane systems should not be used while driving down the road as they present an increased risk. If you're worried about how to keep your 120V absorption style RV refrigerator cold, then consider connecting a small inverter to your 12V battery bank. Or, if your fridge is already powered by 12 V, it can run off the battery all day without issue.
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The OPD, or "overfill protection device", is a required safety valve on all 4 to 40 pound propane cylinders. Propane OPD valves are located inside the bottle and only activate when the liquid propane reaches a certain level. This is similar to how a float valve in a toilet works; when the water bowl fills up to a specific point, the flow of water stops. It's crucial to be aware of this because the OPD valve doesn't restrict cylinder discharge, it only halts inflow when filling.
Finally, Propane manufacturers add an odorant called Ethyl Mercaptan which smells like sulfur (rotten eggs) to alert customers of a potential leak. Therefore, if you smell sulfur, pay attention and take appropriate action in case of a leak. If you detect propane around the tanks, immediately turn off the system. Allow it to air out before making sure your connections are securely in place. After that, switch on the tank and wait 10 seconds, and then check for leaks.
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To check for leaks, mix liquid dishwashing soap with water. This will produce the most bubbles and is what's most commonly used. If you're using a spray bottle, make sure to adjust the tip of the sprayer so that it produces a directed stream. The stream should provide enough of the soapy mixture to not only reach any recessed connections but also create bubbles if there's actually a leak.
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If you're not sure where the leak is, shut down the system and call a professional.
Filling your Tanks - The Right Way.
Here are a few things to remember when you're getting your propane tanks refilled. Though I've had people who know what they're doing fill my tanks before, more often than not it's someone new to the job. To make sure your tanks get completely filled, but not overfilled, throughout the process have the bleeder valve loosed up with a screwdriver (Yes, right from the start, open the bleeder valve). This method for filling your tank allows a small amount of gas to escape, thereby making more room for liquid propane. This will stop you from having a short-fill situation. Stop the filling process once the valve starts spitting out liquid propane. At this point, that signifies the tank is 80% full. This is both the recommended limit for all propane tanks and adding much beyond this point will also increase your chances of breaking your OPD Valve and float assembly.
Filling your tanks correctly will ensure you have the maximum amount of propane available and help to prevent potential safety hazards. Taking extra precautions when it comes to refilling your tank with propane can save you money, as well as keep you safe!
OPD Valve Assembly
Selecting the right size propane tank
Comparison of 20, 30 & 40 Lb Propane Tanks
RVers rely on propane to heat the camper, the hot water tank, the stove, the oven, the fridge so choosing the right size for your adventure is key. In this section, we will provide in-depth details about the size, capacity, lifespan, and cost of 20, 30, 40 LBS propane tanks. Furthermore, we will cover various scenarios for propane usage this way you can be sure you're prepared for your big trip.
Shape and Size
All propane tanks, in this size range, are cylindrical, with a collar carrying handle and OPD valve at the top to prevent overflow. The bottom of the tank has a round base so it can stand upright. Some tanks, however, are designed to be horizontal and have bracket feet across the round part.
Here is the list of dimensions for your reference:
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The Height- For 20 Lb tanks, the height (distance from top to bottom surface) should be between 17” and 19”; for 30 lbs tanks, it should be between 23” and 25” ;for 40 Lb tanks, it should be between 29” and 31" depending on the brand.
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The Diameter- All 20, 30, and 40 Lb tanks have a the diameter between 12"~14"
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Weight
When choosing a propane tank for your RV, you might think that the lighter option is always better. But that’s not necessarily true. Heavier tanks like 30- and 40-pounders have their own advantages.
Remember: there are two weights to consider when it comes to any propane tank:
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The weight when the tank is empty (tare weight or TW)
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The weight when the tank is full of propane
The tare weight is the weight of an empty cylinder. You can find the tare weight printed on the tank's collar, where it will say something like "T.W.: 16.6 Lb."
The tare weights for each cylinder option are as follows:
- Tare Weight of 20 Lb propane tank: 16.6 pounds
- Tare Weight of 30 Lb propane tank: 23.5 pounds
- Tare Weight of 40 Lb propane tank: 30.6 pounds
The weight of a propane tank increases by ~2.3x its Tare Weight once filled with propane. The density of propane is 493 kg/m3 or 30.8 lbs/ft3, which means that 1 gallon of propane weighs 4.4 pounds. With this information in mind, we can calculate the full weights of various propane tanks. As you can see from the table below, a 20lb tank has about 20 pounds of actual propane in it. The other two tanks sizes have an equivalent amount of poundage, hence the naming convention.
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20 Lb tank, Propane weight: 19.8 pounds which is 4.5 gallons
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30 Lb tank, Propane weight: 30.8 pounds which is 7.0 gallons
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40 Lb tank, Propane weight: 41.36 pounds which is 9.4 gallons
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Total weight of the tank and propane
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Total weight of a full 20 Lb propane tank: 36.4 pounds
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Total weight of a full 30 Lb propane tank: 54.5 pounds
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Total weight of a full 40 Lb propane tank: 71.96 pounds
Depending on the brand of tank, the figures could be 2-5 Lb heavier due to the tank construction.
Tank Capacity and Burn-Rates
A common question regarding propane tanks is "How long does a propane tank last in an RV?" To answer that, we need to consider the capacity of the tank and how much propane we're planning to use.
It's standard procedure that when filling a LP cylinders you target 80% of their space to allow for propane expansion due to temperature changes. For example, a 30 Lb propane tank can hold 9.4 gallons of propane but it's only filled to 7.5 gallons. Filling a propane tank to the brim can result in a broken valve seal or even a explosion.
How long will a 30 Lb propane tank power a RV Generator?
Consider this scenario, let’s say your generator is 5000W, 10HP and it’s working under 50% load. In these four steps we'll be able to calculate the approximate life of the tank.
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The volume of the propane in a 30 Lb tank is 7.5 gallons.
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Total BTU capacity of the propane is (7.5 Gallon * 92,000 BTU/Gallon) is 690,000 BTU.
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The BTU consumption of the generator is 50,000/hour.
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The runtime of the generator is (690,000 BTU / 50,000 BTU/hr) is 13.8 hours.
A 10HP, 5000W generator can run for 13.8 hours at 50% load with a full 30 Lb propane tank.
Here's a chart of how long each tank size would last under the same circumstances.
If you want to calculate the BTU/hr consumption of other RV appliances, here is a chart with some average ranges-
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RV Grills: 8,000-10,000 BTU/hour.
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RV Refrigerator: 1500-1800 BTU/hour
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RV Furnace: 20,000-30,000 BTU/hour
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RV Air Conditioner: 5,000-12,000 BTU/hour
If you need the exact data on BTU consumption, you can find it in the product body or user's manual of your appliance. With this information, you can easily calculate how long your propane tank will last using this method.
Recertification
The average recertification period for propane tanks is every 5 years, although some tanks may last up to 10 years. You can tell when a tank needs to be re-certified or replaced by looking at the expiration date on the tank collar. The cost of re-certification ranges from $10-$50, depending on the size of the tank. Shop this service around, it's going to fluctuate from place to place. A new tank may be a better investment at this point.
Gear Selection
Coming Soon.... Click on my Propane Buyer's Guide if you want to see which propane tanks and accessories I recommend.
In 2021, I uncovered the ultimate way to take my family of four on thrilling excursions around the country without having to forgo our everyday comforts: RV travel!
I am thrilled to be able to share with you the unique experiences and lessons I have learned on my RV trips, alongside a couple of other endeavors I am passionate about: DIY projects, F.I.R.E., and useful life hacks.
-Cheers to the Grand Adventure Ahead!
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