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RV Furnace Maintenance - Hot Furnace Tips for Cold Weather

The hot days of summer are over, but for a lot of RVers that's no reason to stop traveling. One thing to remember, however: if you want to use your rig during the winter you'll need a good heating system. Here are some tips to assure your furnace is ready for those cold winter nights.

Safety First

Remember, an improperly operating furnace can be downright dangerous. Most RV furnaces are fairly sophisticated; and unless you are a competent "do-it-yourselfer", leave major furnace repairs to a qualified RV service technician. Even if you are a good mechanic, have a professional do an annual inspection on your furnace.

One of the most things is to assure that the furnace gets proper airflow both in and out. Don't store items in spaces directly beside or on top of your furnace. In addition to being a potential fire hazard, that kind of clutter can interrupt the airflow to the furnace. When a furnace's intake airflow is restricted, the fan motor can speed up to increase airflow, altering the burn characteristics in the combustion chamber. This results in leaner, hotter flame and could lead to your furnace overheating. Overheating can cause the safety devices on the furnace to fail, damage the electronic components, and even crack the combustion chamber.

Periodically check the furnace for proper duct connections as well as for collapsed ducts. Make sure the ducts are clear of obstructions and are as straight and tight as possible. Check that external vents are not clogged by bird nests, bug nests, or other debris.

If you see a soot streak on the exhaust vent, turn off the furnace immediately and get a professional to look at it. If you continue to use the furnace after spotting the warning signs, you could end up injured or with a fire in your RV. Possible causes of the soot streak include a dirty burner. Some cast iron burners need to be cleaned every couple of years. Other possible causes include low gas pressure, and obstructed intake, a blocked exhaust vent, or a bad fan motor.


If the furnace is not working properly, there are a few checks you can perform to diagnose the problem. If the blower is not operating, check for a blown fuse, damaged wiring, loose connection, bad fan motor, or malfunctioning thermostat. If the blower runs but there's no flame, check to see that the furnace is getting propane. Other causes for a poor performing furnace include low voltage or a blocked exhaust or intake. RV furnaces are designed to operate at voltages between 10.5 and 13.5 volts DC. Low voltage will keep the blower motor from operating at the proper speed to start the ignition sequence. If the burner ignites but goes out after a few seconds, check for low gas pressure, obstructed intake or exhaust vent, or a dirty electrode. Low gas pressure can usually be traced to malfunctioning regulator, crimped or obstructed fuel line, or a depleted supply in the fuel tank.

Periodically have the fans cleaned and blow the dust off the rest of the components. Electronic ignition furnaces are designed so once the thermostat closes and calls for heat, the blower will run until the temperature set on the thermostat is reached, the battery goes dead or the motor wears out. Many RV furnaces are fitted with a time delay switch to handle the relatively high current needed to run the blower motor and to let the blower run for 45 to 90 seconds after the thermostat temperature is reached.

Replacing a Furnace

When replacing a furnace, make sure the new furnace has the same BTU rating as the one being replaced, or at least a close equivalent. An oversized unit can supply too much heat, causing rapid cycling and reduced comfort levels. If you do install a higher capacity furnace, make sure the ducting, return air amounts, clearances and gas pipe size are all compatible. Use recommended replacement parts approved by the manufacturer. Finally, don't forget to install both a carbon monoxide detector and a smoke detector. Then check both often to ensure they work properly.