How Does an RV Propane Furnace Work?

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Many who go RV camping prefer to stay indoors during winter. For these folks, winter is about cozying up at home, not traveling, and living it up in a camper.

However, others like to get more adventurous during this time. If you belong to the latter group, we have some good news for you.

RV camping is possible in cold weather! Especially if your camper has an RV propane furnace. But how does an RV propane furnace work?

In this guide, you’ll learn how your RV’s propane furnace works and some important safety, maintenance, and troubleshooting tips!

What is an RV Furnace, and How Does it Work?

RV furnace thermostat

Simply put, an RV furnace is a main heat source that uses propane and electricity. Propane heats the furnace system, while electricity enables the fan to move.

Working with such a forced-air system is not at all complex, as you just need some basic things like a thermostat, a blower motor, and some ductwork.

When you set the thermostat higher than the RV’s temperature, the blower motor gets activated. Gradually, the heater begins to warm your RV as propane burns to create hot air, and the ducts in the system blow this air out.

In short, an RV furnace requires propane and electricity: propane for creating hot air and electricity to turn on the heating system and run the fans.

Equipping your RV with this type of furnace is relatively inexpensive. This system will not only heat the RV but also prevent the pipes and tanks from freezing since the ductwork typically runs under the vehicle’s floor.

Which Propane Heater is Considered Best for Your RV?

Now that you know the working of an RV furnace, you’re probably wondering which propane heater you should invest in.

If you’re looking for a ducted propane RV heater, look for Dometic (formerly Atwood) or Suburban models, as they are known to be durable and well-made heating systems that will last for years. However, these are expensive, and you’ll need to hire a professional to install such a furnace system.

If you have budget constraints and are looking for affordable alternatives, go with space heaters. Whether it’s an electric space heater or a propane space heater, they’ll fit the purpose without you spending a hefty price. If your camping destinations provide electric hook-ups, electric heaters will prove a great money-saving option. See my top electric heater picks for RV use.

On the other hand, propane space heaters are recommended for people who enjoy staying outdoors while boondocking. These heaters use less fuel as compared to RV propane furnaces.

However, the downside of space heaters is that they won’t keep the “basement” of your RV warm, so your tanks and pipes will likely freeze in extremely cold weather. And you may need multiple heaters to heat the vehicle throughout.

How Much Propane Does an RV Furnace Use?

The amount of propane an RV furnace uses will depend on its BTU rating, amongst many other factors.

We covered this extensively in our guide, How Much Propane Does an RV Furnace Use. But, let’s quickly look at a real-life example using the DOMETIC Mojave Large Doored Furnace.

The DOMETIC Mojave Large Doored Furnace is rated at 40,000 BTUs (British thermal units) per hour. One gallon of propane has 91,502 BTUs. So essentially you could run your furnace for roughly 2.3 hours off 1 gallon of propane.

How long you can run an RV furnace on propane will depend on the size of the propane tank. Your typical 20 lb. propane tank holds 4.6 gallons of propane.

So, how long will a 20 lb. propane tank run an RV furnace?

Using the example above, we simply take 4.6 (gallons in a 20 lb. tank) X 2.3 (the hours our furnace will run off 1 gallon). You can run an RV furnace using a 20 lb. propane tank for 10.5 hours.

Tip: Check out our free propane usage calculator in our popular guide, How Long Does Propane Last in an RV? to easily calculate the propane usage of all the appliances in your setup, including your RVs furnace, hot water heater, and more.

How to Maintain Your RV Furnace for Uninterrupted Heating

To ensure that a system works efficiently, you must maintain it thoroughly. The same thing applies here. However, maintaining a forced air heater is not at all hard.

How to maintain an RV furnace:

  • Periodically check that the ducts are connected properly to the furnace, as well as to the registers.
  • Keep the registers and furnace clean.
  • Check whether ducts have any holes, tears, or obstructions. When found, repair them immediately.
  • Keep the air intake and exhaust vents clean and clear.

As your motorhome is constantly exposed to external elements, mice, birds, etc., can potentially make their way through vents. Even dust and debris can accumulate over time around registers, especially if you travel through remote areas. So, it’s recommended to carry out RV furnace maintenance at least twice a year to keep the system running efficiently.

How to Repair Your RV Propane Heater While Camping

Your propane RV furnace may be in great working condition, and you may have double-checked it before leaving for camp, but still, there is a chance that the gas furnace system can break down.

And let me tell you, they never break down at a good time! So, here are some RV propane furnace troubleshooting tips for covering a few general issues.

RV furnace motor isn’t working

In the general scenario, you’ll hear the blower motor kick on when you switch on the RV heater. If you don’t, it’s a sign that there’s an electrical problem.

So, what will you do here?

The first thing is to check your furnace fuse. Is it blown out? If yes, replace it with a new fuse to get the system up and running again. But, if the fuse isn’t the issue, then the problem may be:

  • the thermostat
  • a bad blower motor
  • malfunctioning module board

If it’s not the fuse, I recommend you contact a certified RV technician to inspect the heating system.

RV furnace motor is working, but the system isn’t working as usual

In this case, you may hear the blower motor kick on, but nothing happens afterward. This means you’re likely encountering a failed sail switch.

In some cases, the switch may be stuck, so you’ll need to work a bit to bring it back to normal. In other cases, you’ll need to replace the switch altogether.

Here’s a quick video on troubleshooting an RV furnace with a dirty sail switch.

Troubleshooting An RV Furnace With A Dirty Sail Switch

Apart from this switch issue, a bad high-temperature relay can also contribute to this situation. Testing the voltage here may help you solve the problem.

RV furnace pilot won’t light

In this scenario, your blower motor is running perfectly, and you hear the clicking noise of your igniter and the thumping of the gas valve, but the pilot won’t light.

The issue may be as simple as air in your propane lines, which will need to be purged. Check out our guide on how to purge RV propane lines for a step-by-step process to remedy this.

The issue may also be a bad gas valve, a bad igniter placement, or bugs. Yes, bugs are likely to be found in the combustion chamber and gas tubes. So, cleaning those areas thoroughly may solve the issue, as well.

Important RV Propane Furnace Tips

Safety is Your Priority

Using a propane furnace requires you to be vigilant about certain things. After all, you need to be prepared for worst-case scenarios, as a propane leak can even prove fatal.

So, if you’re planning to install a proper propane furnace system in your RV, it’s important to equip your RV with both a propane detector and a carbon monoxide detector. Be sure to test the RV propane detector regularly to ensure it’s working properly.

Proper Ventilation is a Pre-requisite

To allow your RV furnace to work smoothly and efficiently, it is important to create the necessary airflow.

For this, you need to ensure two things:

  1. The RV propane heater is properly vented
  2. The air intake remains undisturbed.

Additionally, don’t cover your vents when the furnace is on. This will facilitate proper ventilation.

Know the RV Furnace Process

We’ve discussed this already, but let’s brush up on it quickly. It will take a few seconds for your RV furnace to start working as soon as you switch on the thermostat. Once it does, wait for around half a minute to feel the warm air coming through the vents.

Don’t panic if you hear the blower run for some time. It’s normal, and you’ll hear it till the desired temperature is met and the flame goes out.

Dusty Smell Isn’t An Issue

You don’t need to worry if your vent gives out a dusty smell. Your vents and ductwork may have accumulated dust, dirt, and debris over time, and these will burn as soon as your furnace starts working, leaving you with such a smell for some time.

Propane Smell Can be an Issue

While the dusty smell isn’t an issue, the propane smell can be. So, as soon as you smell propane, stop the flow of LP gas, and create good ventilation by opening the doors and windows of your RV.

Next, you’ll need to try to identify the source of the propane leak. Check out our guide titled RV Propane Detector Keeps Going Off? Do This! for tips to help you find the propane gas leak.

Soot Accumulation around the Vent

If you see soot accumulating around the exhaust vent, the fuel and oxygen have not mixed properly. This results in fuel being unburned. To avoid this, check and remove soot if you find any. Also, adjust the airflow to the burner flame to prevent soot accumulation again.

Maintain the LP Gas Regulators

Regardless of what type, style, or brand your RV is, it will come equipped with LP gas regulators that tend to wear out over time. Having a bad regulator can contribute to furnace issues, as it will hinder the efficiency of your propane supply.

So, to avoid this, it’s best to replace them periodically. If not, at least check them and maintain them at regular intervals. Checking your regulators isn’t complex. All you need to do is turn on the furnace and observe the flame in the burner. If you see it in blue, it’s fine. If it’s yellow, you may need to replace it. Be sure to replace it with one of our top 3 picks for the best RV propane regulator.

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