The Best Guide to Turning Up the Heat When Your RV Furnace Blower Comes On But Won't Ignite

As idyllic as camping is, problems happen. Sometimes, the AC doesn’t cool the camper enough. Other times, the awning gets stuck, leaving your family baking in the sun. Winter has its share of issues too, like when the RV furnace blower comes on but won’t ignite. Nothing can spoil an autumn or winter trip quicker.

Several things could cause this conundrum. They run the gamut of easy fixes to major repairs. A few questions and an assessment of the problem can point you in the right direction for a solution. Begin with the most straightforward fixes and move on from there. Sometimes, it’s only a dirty connector affecting your furnace’s performance.

Remember that your RV furnace won’t run continuously just like the one you have at home. That’s especially true if your rig is well-insulated. There are two primary reasons for it not working correctly. Either something is interfering with the igniting mechanism, or it’s not getting enough or any fuel.

Tackling the Obvious Causes

Don’t panic if you have a problem with your rig’s furnace. It’s certainly not a time to start scanning the pages of RV Finder. Often, it’s a DIY fix. The easy solutions are often the least expensive, making them the best place to start.

Begin with the pilot light and make sure that it’s lit. This step applies to older models since RV manufacturers use a direct spark ignition instead. Then, it’s on to the propane tank. Check that it’s on and ready to fire. The next thing to do is to isolate the problem. Is it just a furnace problem?

Go over to the stove and turn on one of the burners. You should see just blue and no other color. If you see yellow flames, that could mean a shot regulator on the tank or an electronic control board on the unit. Sometimes, the connectors get dirty, which can affect the performance of the board. Clean the contacts to see if that resolves the issue.

Take note of how the flame on the stove looks too. If it stays small or decreases in size, it could be low LP pressure. You may notice that your water doesn’t get as hot either which is a sure sign that you’ve tracked it down. Luckily, it is an easy adjustment to get you back in business.

Airflow Checks

Next, take a look at the furnace and the area around it. Anything blocking the return air vents could prevent the pilot light—if that’s the type you have—from lighting and staying lit. Check the registers inside the rig for any obstruction that could impede airflow.

If the furnace isn’t even starting, it could mean that it’s not getting enough juice. It needs 12 volts to get going. You may have blown a fuse or have a tripped breaker. Another common problem is a bad ignitor. You can test for this issue by turning on the furnace and going to the exhaust on the outside of your rig. If you smell propane, you’ve found the problem. It may need a replacement or just a good cleaning.

While you’re back there, remove the exterior cover and clean the inside of any debris. Look around inside the compartment too for leaves, insects, or anything else that could affect airflow. If you notice soot around the furnace, you’ll need to take it into the shop. Most manufacturers recommend regular inspections of your RV’s heating system anyway.

Soot is likely a sign of a more serious issue like a motor on its way out or a problem with the burner or heat exchanger. It usually means that it’s time for the big guns or a replacement.

Troubleshooting Other RV Furnace Issues

Fortunately, many problems with a camper’s furnace have signs that point directly to the culprit and eliminate the guesswork. For example, if it sounds like it’s trying to start but not igniting, it can mean possible damage to the ceramic housing since the spark isn’t making it to the burner tube. If both the fan and furnace don’t work, it’s most likely a power issue.

Likewise, a furnace that ignites and then goes off may indicate faulty wiring or a bad gasket. If it runs continuously even if you have the unit turned off, you probably have to replace the thermostat. When trying to find the source, pay attention to what’s working and how it’s functioning. Take note of any disagreeable odors which can also point you in the right direction for a fix.

A Problem With the Thermostat

Now, turn your attention to the thermostat. This device won’t ignite your furnace, per se. It sends a signal to the unit for it to take the reins. If you have both air conditioning and heat, make sure that it’s set to the latter. Put it at a high temperature and wait. The furnace, like the one you have at home, won’t start right away. Instead, it will release any unburned gas first before it starts, usually within a minute.

If you hear the fan but not the thud of the furnace kicking on, you’ll need to dig deeper. Remove the cover and locate the anticipator adjustment. It’s a wire that may or may not have insulation around it, depending on the model. It’s live, so it will generate heat. Look to make sure that it hasn’t melted into the housing. If it has, you probably need a new thermostat.

Examining the Furnace

If your troubleshooting hasn’t solved the issue, it’s time to look at the unit itself to see if it’s the cause. The interior of the furnace has an internal sail switch. Its purpose is to regulate how it responds to airflow. If it’s not enough, the RV furnace blower comes on but won’t ignite. You’ll hear the fan running, but you won’t get any heat.

If the furnace isn’t running up to speed, it can point to a power issue. That may mean a spent battery or one on its last legs. Damage to the wiring can also cause it to occur. Check all the connections to make sure everything is intact and that nothing looks frayed. You can also tighten the sail switch while you have the unit open.

Take a look at the blower wheel. Dust and debris can hamper its performance and shorten the life of your furnace. It can also prevent the sail switch from closing and, thus, keeping the unit from igniting.

Check the position of the thermocouple. It is a heat-sensing device that keeps the pilot light lit. If it doesn’t sit upright, it can interfere with its operation. Look for any cracks or damage to see if you need to replace it.

You may also have a shot gas valve. This part is often far inside the unit and not easy to remove for testing. A technician would use a multimeter to make sure that it checks out between 30 and 50 ohms. Replacing it is an advanced DIY repair that might be out of the wheelhouse of many RVers. If in doubt, take it to an RV repair shop.

Routine Maintenance for Your RV’s Furnace

You can avoid many problems with your rig’s heater with some simple maintenance. At the start of the season, vacuum out all the registers and return air vents inside of the RV. Make sure that all of them are fully open. You should follow the basic troubleshooting steps to identify potential problems before they become major hassles.

Don’t forget the ductwork, either. Inspect them for any damage and replace them as needed. Take off each register and vacuum the inside as far as you can reach. These areas are notorious for attracting mice and other rodents because of the residual warmth they offer.

Take the same care inside of the furnace cabinet. Use compressed air to clean the vents and internal components. Inspect the circuit board and wipe off the contacts with a soft microfiber cloth. You can also wipe down the inside to remove dust that could end up gumming the works.

It’s also a smart idea to give your furnace a trial run in the summer. It’s better than finding out you have an issue in the summer than when it’s freezing outside. While you’re at it, also check your carbon monoxide detector too. It’s an easy task that can have profound impacts.

You should also clean out the exhaust and intake on the outside of your camper. Obstruction in the former can become fire hazards since it gets hot when the furnace is running. Your battery will also need some maintenance too for preventing issues with the sail switch. Keep it at least at a 50-percent capacity to avoid power issues.

Other Tips for Staying Warm in Your RV

Preventive measures can help you stay cozy if the temperature hovers around that spot where you could either take or leave the furnace heat. After all, keeping it warm in your travel trailer isn’t just about you. It’s also essential for your rig. The last thing you need is a burst pipe in the middle of the wilderness. You’ll save money which can make RVing more enjoyable and affordable for you.

You can skip the water hookup and rely on bottled water instead. Yes, it’s a hassle, but it is better than the alternative. If you must have it, keep things from freezing with a small space heater plugged directly into your electrical hookup or heat tape on the lines. While it may seem counterintuitive, running a dehumidifier is also a smart option with a closed RV with small living quarters.

You can also insulate your rig just like you would at home. Heavy curtains and plastic film over the windows are a godsend when it comes to reducing drafts. If you plan on staking camp at one site for a while, invest in an RV skirt. It can protect your tanks from freezing and keep snow out from underneath the camper. That way, you won’t be forced to start checking out RVs for sale.

The wise RVer will anticipate trouble before it starts. Keep extra fuses in the rig, just in case. You should also keep some tools and a multimeter onboard. It doesn’t hurt to have a backup in case of a furnace failure. A small space heater and an extra extension cord are invaluable on a cold night.

Problems with your RV’s furnace are avoided easily if you maintain your rig properly. The start of the camping season is the ideal time for some welcome spring cleaning to ensure trouble-free vacations. You can identify many problems with your heater quickly, with several being an easy fix. After all, nothing should interfere with your time to get away from the hassles of everyday life.