RV Furnace Won’t Ignite

Your RV furnace is an important part of your rig. It keeps your RV warm on chilly nights and generally makes your camping experience more comfortable. An RV furnace that won’t ignite can be malfunctioning for a variety of reasons. To identify what is causing your furnace to fail to ignite, you need to troubleshoot by checking the common causes that could be at the root of your problem.

Troubleshooting RV furnace that won’t ignite

Check the battery

Any problem with the battery that supplies the 12 V power to your RV can result in an RV furnace that won’t ignite. The RV furnace depends on a 10.5 V power supply to function, and if your battery is not supplying this voltage, then the furnace won’t ignite.

The best way to check if your battery is working is to use a multimeter. The multimeter will show you the exact voltage output of the battery. With this reading, you can then determine if the problem that is causing your furnace not to ignite lies with the battery or elsewhere.

Another way to troubleshoot the battery is to check whether the blower runs, but the furnace won’t ignite. If this is the case, then the problem is low voltage since the furnace needs 10.5 V to function, but a blower can run on under 10.5 volts.

Check the Thermostat

If your battery is working, then the next step is to check your thermostat. Set the thermostat at a higher temperature than the room temperature or switch on the fan. The furnace should start releasing heat. However, if the furnace still won’t ignite, its time to check the sail switch.

Check the sail switch

The sail switch is an internal flow switch in the furnace. When the airflow is not enough, the sail switch stops the furnace from igniting. When this switch malfunctions, it will cause your furnace not to ignite. In some cases, the sail switch can just be stuck, and flicking it will get it working again.

Check the fuse

Typically, your furnace will have a fuse between the DC supply and the electric furnace board; however, if this fuse blows, then your RV furnace won’t ignite. You can tell if the fuse is blown if it has a blackish appearance.

If your furnace runs on propane, here are some troubleshooting steps to use to diagnose why your RV furnace won’t ignite.

Check your gas supply

If you are out of propane, your RV furnace won’t ignite. Turn on the furnace and check the RVs exhaust. You should be able to smell propane when the furnace is on, if you cannot smell the gas, then you are likely out of propane.

You can also verify your gas supply by turning on your gas stove. If the gas stove is working, then your RV furnace is not malfunctioning because of a lack of gas.

Check the gas valve

When the gas valve on your furnace gets clogged, it will not supply propane to the furnace, which will, in turn, result in the furnace not igniting. If the valve is clogged or damaged, it needs to be replaced.

Check the furnace ignitor

If you have enough gas and the gas valve is working, the next step is to troubleshoot the furnace ignitor. The furnace ignitor may be covered in dirt, causing it not to ignite properly, or there might be faulty wiring between the ignitor and the circuit board. If this is the cause, you need to have a technician look at it and repair your ignitor.

Other Common RV Furnace Problems

The heat from the RV furnace is not enough

Apart from the RV furnace not igniting, in some cases, you will find that your RV furnace ignites but does not have sufficient heat. When you are getting little or no heat despite the furnace being on, the most common cause is insufficient airflow in the furnace. Airflow problems are typically due to ventilation problems in the furnace.

Your RV furnace is making a loud noisy

A noisy RV furnace is a common problem in RV furnaces. This problem is commonly caused by accumulated debris and dirt in the furnace air registers. Cleaning out the furnace should help in reducing the noise from your RV.

The loud noise in your furnace could also be due to debris in the exhaust vent.

What If The RV Furnace Won’t Stay Lit

Sometimes your RV furnace will ignite but does not stay lit. Here is what to do in such a case.

a) Check the thermocouple

When the thermocouple malfunctions, it will not detect heat from the pilot light. As a result, it will block the gas valve in effect, preventing the furnace from staying lit. Have a professional repair the thermocouple if you suspect that it is malfunctioning as it is an important safety feature in your RV furnace.

b) Check the thermostat

If your thermostat is faulty, you may have a problem with the RV furnace staying lit. You can check if your thermostat is faulty by replacing it with a temporary one to see if your furnace will stay lit. If the furnace stays lit, then the thermostat was the problem and needs to be repaired or replaced.

c) Is the airflow restricted

When the airflow in the RV furnace is restricted, your RV furnace may ignite but not stay lit. Dirty and clogged air ducts or vents cause the heat exchanger to overheat. When this happens, the gas valve closes, restricting airflow in the furnace. This airflow problem can be resolved by cleaning or replacing clogged air filters.

Tips for Replacing your RV Furnace

If your furnace is malfunctioning or works sporadically, it may be time to replace it and get a functional furnace for your RV.

Choose between an electric and gas furnace:

 Each type of furnace has its pros and cons. However, gas furnaces tend to be less energy efficient and noisier. An electric furnace will be more expensive to purchase but will save you more since it is energy efficient. Electric furnaces also tend to be quieter than gas furnaces.

Choose an RV furnace that will suit the size of your RV: 

Furnaces come in different sizes, and you should pick one that will fit well in the heating area of your RV.

Depending on your budget, there are plenty of furnace options to choose from:

Look for a good quality brand that is durable and will last for a long time. Some of the best brands when it comes to RV furnaces include Artwood RV furnace, Camco RV furnace, and Suburban RV furnace brands.


If your RV furnace won’t ignite, it means that you will not get proper heating in your RV. To avoid having to deal with a malfunctioning RV furnace while camping, always check your RV furnace before setting off on your trip. While some of the issues behind an RV furnace that won’t ignite can be fixed easily, it is always best to consult a professional technician if you are not sure how your furnace works. It is also important to replace furnaces that function intermittently since they are more likely to catch you off guard and leave you in a fix.