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Troubleshoot Your Faulty RV Furnace

On a chilly fall or winter day, your RV furnace is your best friend. But when that cozy space turns chilly because of a malfunctioning furnace, it can feel a little overwhelming to deal with.

Luckily, most RV furnaces are relatively simple, and, therefore, so are many of the solutions to common problems.

Here’s what you should do if a faulty furnace has the chill creeping into your rig. 

How Does an RV Furnace Work?

An RV furnace isn’t much different from any other gas-powered furnace you’d find in a home or other building. Typically, the process starts with your rig’s thermostat, which detects a temperature below the threshold you’ve set.

It then signals your furnace to begin operating in several key ways. 

First, blowers turn on to begin to pull air from your RV and heat it. At the same time, gas begins to flow and ignites via a spark.

This burning fuel warms a chamber which then transfers its heat to a heat exchanger. The air from your rig flows over this heat exchanger and warms up before it blows back into your living space. 

This process continues until the thermostat detects a temperature above your threshold, at which point it signals the furnace to turn off. The gas flow stops, as do the blowers, and the furnace cools down gradually until its next use.

The same principles apply for systems without a thermostat, only you have to manually turn the furnace on and off when you’re cold or warm. 

Keep in Mind: An RV furnace isn’t the only way to stay warm this winter! Check out these 5 Ways to Heat Your RV This Winter.

RV in the fall.
As the weather changes, keep warm with an RV furnace.

Common RV Furnace Issues and How to Address Them

Now that you know how your furnace works, it’s much easier to troubleshoot any issues you may encounter. Here are some of the most common problems and what you should do if you encounter them. 

Furnace Is Running But Not Providing Heat

If your thermostat seems to be working properly and you can hear your blowers operating, but you aren’t getting any warm air, there are a few possible culprits.

The parts of your furnace’s electronics that start the flow of gas, open the gas valve, or spark the fuel may be malfunctioning or have failed. Furnaces generally also have fail-safe devices that shut down the system if they don’t detect a flame, preventing unlit gas from seeping into your RV. 

Alternatively, you may be out of fuel for your furnace. First, check to ensure you have gas for your furnace.

If the problem persists, get a mechanic to check out your furnace.

The Burner Keeps Going Out

In many cases, a furnace that goes out repeatedly is becoming too hot, triggering parts of the system that automatically shut it down. With RV furnaces, a lack of airflow over the heat exchanger usually causes this.

Check for and eliminate any obstructions that might be preventing full airflow through your furnace as a first step. You may also want to clean your heat exchanger, as dirt and dust can potentially cause unexpected heat readings.

Continual furnace maintenance will ensure you stay cozy in the colder months.

It’s Starting Up and Then Stopping

When the symphony of your furnace unexpectedly stops and starts, it’s time to look to the conductor — your thermostat. More likely than not, it’s receiving an incorrect reading and adjusting the temperature accordingly.

For example, a vent may be blowing hot air onto the thermostat, or it could be sitting in a drafty portion of your rig. 

Try to rule these issues out first. Afterward, check to ensure the thermostat and furnace are communicating properly. You might have to replace the thermostat or do a more involved repair or replacement of your furnace’s electronics. 

The Blower Won’t Start

A furnace blower that simply won’t turn on could indicate a variety of issues. The issue may lie with your thermostat, which may either not be properly sensing the temperature or have wiring issues.

You may also have issues with any of the various electronic switches or sensors your furnace uses to draw power, start the gas flow, or ignite the fuel. Finally, you may be dealing with loose wiring or even a failed blower motor.

This is, unfortunately, one of the most challenging issues to diagnose and may require some help from a mechanic. 

It Works Once But You Can’t Restart It

If you successfully used your furnace but now find it mysteriously won’t start, you may be dealing with a blockage somewhere in your air system.

Check both the interior and exterior vents and ducts to ensure air can flow freely. Eliminating any impediments to airflow will solve this problem much of the time. If it doesn’t, a professional may have to take a look. 

Woman bundled up in blankets
Staying warm on the road is crucial to your well being!

It Turns On But Never Shuts Off

You certainly can have too much of a good thing when it comes to heat. If your furnace fires up and doesn’t ever turn off even at temperatures far above what you’ve set, your problem likely lies with your thermostat.

Check the connection to ensure the furnace and thermostat are communicating properly.

If so, you may have a fault in your furnace’s electronics, which you should get repaired as soon as possible.

The Fan Is Making a Weird Noise

This can be among the more annoying furnace issues, as it may occur even if things are otherwise operating normally. If you’re hearing a weird noise from your fan, it’s likely rubbing against something as it spins.

This could be part of the fan’s housing or an obstruction that made its way into the system. Clear any obstruction and readjust any errant parts of the housing to see if this resolves the problem.

If not, you may also have an issue with your fan’s motor, which would require professional help.

The Furnace Won’t Run Off Battery Power

Some RVers find their furnace works well when connected to shore power but won’t turn on at all when they’re operating off their batteries.

As you might expect, the issue here likely has to do with the state of your batteries. Whether it’s a result of corrosion, bad wiring or connections, or simply a degraded battery, your furnace isn’t getting the voltage it needs.

Check your connections and, if all looks normal, check your connections and consider replacing your rig’s batteries, which should resolve the issue. 

Pro Tip: When it’s time to turn the heat on, it also means it’s time to start winterizing your RV. This is How To Winterize Your RV?

Keep Up With Normal Maintenance to Avoid Issues

There’s an old saying that an ounce of prevention is worth a pound of cure. That’s particularly apt when it comes to your furnace.

Regularly maintaining your furnace by changing the air filters, cleaning the ducts, and getting professional inspections and checkups will catch most problems early.

As simple as it is to troubleshoot many of these issues, it’s far easier not to have to deal with them in the first place. Your fellow RVers will thank you when winter arrives.

Have you ever had to do your own maintenance on your RV furnace? Let us know in the comments below!

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