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Dometic RV Furnace Troubleshooting | 13 Problems & Solutions

Last Updated on September 25, 2023

You must have a heat source when traveling with RV in cold weather. You might take a Dometic RV furnace for this purpose. The stove is the source of heat, but it also needs to get refueled on time.

If you use it for home RV heating, you may face problems while maintaining the entire unit. This article will discuss common RV furnace problems and provide Dometic RV furnace troubleshooting tips so that you can easily fix the problem on your own.

Most of the problem while using the furnaces is a lack of proper care. Unknowing users can damage it if not handled properly. So keep reading this article to keep your unit in good condition.

Why is Knowing How to Measure Trailer Tire Size Important for RV Furnace Troubleshooting?

When it comes to RV furnace troubleshooting, measuring trailer tire size may seem unrelated. However, understanding this aspect becomes crucial for a simple reason. Incorrect tire size can affect the RV’s weight distribution, leading to improper furnace operation and potential safety hazards. Therefore, knowing how to measure trailer tire size is essential for ensuring a properly functioning RV furnace.

Dometic RV Furnace Troubleshooting Tips:

furnace shuts

The RV furnace is typically powered by one of the following: shore power (AC), battery power (DC), or LP (propane). The type of fuel used will dictate which system it should be connected to.

When properly installed, the RV furnace should direct warm air throughout the entire coach within about 15 minutes after the propane tank, battery, or shore power has been turned on. If you experience any problems with your RV furnace, many possible causes need to be examined.

There are many common rv furnace problems associated with the operation of the furnace, including:

Problem 01: The Furnace will not Turn On:

A thermostat problem is the most common cause of the unit not working. If you face this rv furnace issue, you may solve this problem without getting professional help.


Check with your thermostat. You must see two different control boards, one for the furnace and another for the cooling system. If you find any problem with your thermostat, then replace it immediately.

You can use a multimeter to check whether there is power at your circuit board or not. Set the multimeter on the 20 V DC range and put the probes on different connections of your circuit board. You should see a reading on the meter if there is power on the board.

Problem 02: The Furnace is Producing very little Heat:

If you feel weak air flow, your thermostat might be the reason. You may solve this problem by checking your thermostat control unit.


Check if there is a power supply to it by using a multimeter on 20 V DC range. If you get a voltage reading, then your thermostat might not produce warm air.

If the power is present and if your rv furnace does not work then you must replace your propane tank immediately. You must go for a high-quality product to ensure long service.

Problem 03: The Furnace is not Producing any Heat:

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Sometimes, your system may stop producing warm air due to blocked air vents or blocked propane gas lines. If there is no air flow in the RV heating products then they fail to produce warm air properly.


You must check the cold air returns and registers all over your RV and look for possible blockages and clean them out as soon as possible. You can use a vacuum cleaner to unclog the furnace vents.

If you find no blockages then turn off your rv furnace for five minutes and clear the heat exchanger of any dust or insects that may be stuck in it.

Problem 04: The Thermostat is not turning the Furnace on or off:

A thermostat failure is another common cause of troubles with furnaces. As soon as you notice this issue, replace your thermostat control unit because only new one will work well for a long time.


If your rv furnace doesn’t work when you set the temperature on your thermostat, then you must check it. Set the thermostat at a low temperature and turn off all appliances in its surrounding area to test whether your thermostat works well or not.

If the stove starts working properly, then there might be a problem with too much electricity supply in that area. You must switch off all electrical appliances when you are setting temperature on your thermostat because overloading it can cause issues in the long run.

Problem 05: The Furnace is Cycling too Frequently:

This issue occurs when there is not enough hot air in the RV heating system which forces it to start up repeatedly. It can happen due to weak burner or blocked heating system.


Check the ventilation system of your vehicle again to ensure it is clean and free from blockages that keep blocking its way. You can use a vacuum cleaner to clear the vents after removing any blockage.

You must also check whether there is enough hot air inside your stove by listening for the furnace fan to get turned off after five minutes of starting.

If there is no more hot air inside the stove, you must replace the gas control gas valve because it does not allow enough gas flow to keep the burners running strongly.

Problem 06: The Furnace Generates Excessive Noise:

rv furnace work

When you are using the Dometic furnace, then it may create excessive noise. This is not a very common issue with the heater, but annoying if present.


This problem can be caused by several reasons, so you must identify them if you want to solve this issue. The first reason might be due to your furnace fan belts being too tight or too loose.

If the fan belts are too tight, then your belt may be groaning against another part of the heater or if they are too loose, then they can slap against another surface due to rapid movement.

You must replace the belts with new ones once you find any problem with them. There might be another problem if your belts are fine and still, the heater is making too much noise.

Problem 07: The Furnace is Leaking

Leaking is another common issue that users often face with the heater. There are several scenarios where your unit can start leaking.


Measure the water content in your water heater and then shut down the heater after that. Check for any drops or leaks and take note of their location and size. Wait until they stop leaking. Now check the water content in the tank again and then you will find that there is a reduction in its level.

Now turn on your unit and wait until it gets cold enough to freeze the water inside it, i.e., until all the water that is leaking into your tank gets frozen up.

Once all the water has been leaked out, turn off the unit and use some hot water in the shower. Now drain down all of this used up fresh water and then refill it to check for any leakage.

If you do not want to go through this hassle of measuring out your water content, draining it and refilling it and all and instead prefer a simpler option, then always maintain an emergency repair kit in your campervan or RV.

This kit can be very helpful if you have a leakage issue. It must consist of a water pump, water hose and a heat gun kit. The gun works just like a hand-held hair dryer and is very effective in defrosting frozen water inside your heater.

Problem 08: Smoke is Coming from the Furnace:

If there smoke coming out of your furnace then you need to check it immediately. This is a problem and if not fixed on time can damage several components of your furnace including heater core and combustion chamber.


This issue can be mainly caused due to an overheated combustion chamber or lack of air flow inside the heater.

If your Dometic furnace is not getting enough air, then you might face this problem and if combustion chamber is too hot, then it may result in smoke coming out of your unit.

You must check the connections and openings to ensure that they are proper and there aren’t any obstructions present. If everything seems fine, then you must check the combustion chamber.

Check the unit regularly and keep all openings clear because debris may accumulate over time and obstruct air flow which can cause damage to your furnace.

Problem 09: The Furnace has a Cracked Heat Exchanger:

sail switch

If you feel the heat is not the same as it was before and there is a discoloration on your heating components, then it may mean that your unit has low pressure. This problem can be caused due to a cracked heat exchanger and if this happens then it may result in water leakage and damage to other parts of your unit.


If you find any crack in your unit, then you must replace it immediately because cracked heat exchanger may result in water leakage and damage to other parts of your furnace.

Problem 10: Set Temperature, But Furnace doesn’t Shut Off:

If you are using the furnace and set the desired temperature but it doesn’t shut off then you may have a problem. This can be caused due to several reasons and if you find the issue of temperature not being set, then there are more chances that your unit will not turn off.


You must check all connections of your blower because it might be loose which is keeping the unit turned on with fan running in the ON position. There might be other reasons as well for this issue to occur.

Check your dial control because if it is turned in either direction, then unit will turn ON and won’t shut off even when set temperature is reached. If everything seems fine, then you must check the secondary blower motor switch or limit switch.

These components are responsible for turning off your unit so if they aren’t functional properly, then it may result in high temperature and your furnace won’t shut off.

Problem 11:  Furnace Not Working on Battery:

The furnace will not work when you are on the battery only. You must always connect it to power sources like your car batteries or residential power supply if you want it to run smoothly.

There is a transformer in the unit which converts low voltage into high voltage for operation of the fan motor. So if there is a power interruption in your rv battery, then it can cause unit to stop working on battery.


If the problem is with the wires or cord, then you must check them properly and keep them away from moving parts of the fan motor so that they do not get damaged. If everything seems okay with the connections then perhaps there might be a transformer problem.

It is very rare that your transformer may have problems, but it can happen without any warning if you are not careful about the furnace maintenance. Try to change the transformer with a new one because of this problem.

Problem 12: The Furnace will not Turn off:

working furnace

One of the most annoying problems is when your heater does not turn off while working. This can happen due to several reasons, so you should identify them and take corrective actions.

First, check with the furnace switch and make sure that it is in “Off” position or working properly. If everything is okay then it may be due to a problem with the thermostat.

Thermostats come under a control board and can malfunction without any warning. So if your heater does not turn off after reaching to required temperature then perhaps there may be a problem with the programmable thermostat.

Some furnaces also come with low voltage features that prevent them from shutting down while working on the battery. You must ensure that your heater is powered by your car or residential power supply if you want it to run continuously without any problem.

Problem 13: Unusual Odors:

You may smell an unusual odor while your heater is working if the problem is with any of its parts. This problem is more common with oil furnaces and can be fixed with simple tips.


It is possible that oil leakage has caused the heater to emit a bad odor. In this case, you can solve the problem without getting professional help. Inspect your heater carefully for any oil leakage and find if any of its parts are loose or broken. If you find oil leakage then clean the area properly to avoid further issues.

You may check both filters of your furnace to know whether they are clogged with dirt or not. Clean the filters thoroughly with water and dry them in sunlight for some time. Then place the filters back into their place by using a screwdriver.

The List of RV Furnace Parts

Air Return: Air return is a very important part of the furnace. You can easily find it on the backside of the unit. If you feel less airflow or if it gets stuck then you need to check the position of the vent.

Blower Motor: The blower motor is a special type of motor. If it makes some noise, then the problem may occur in its internal condition.

On/Off Switch & Circuit Breaker: When the heater does not turn on, you need to check the circuit breaker. It can be turned off because of some overload problems.

Combustion Air Intake: A low voltage in the combustion air intake can cause problems. If you feel less air intake when starting the heater, you need to check it.

Combustion Chamber: You can also check the combustion chamber. You need to remove it first then inspect it properly.

DSI: The DSI is an adjustable device that should be adjusted according to the heat requirement.

Ducts: A clogged duct at the intake or exhaust can cause problems. You need to check it.

Exhaust: A clogged exhaust can cause problems with your heater. So, you need to check the clamping system of the exhaust.

Fan Speed Controller: The fan speed controller can be found at the top of the furnace. If it gets stuck, then you need to adjust it.

Heat Exchanger: A clogged heat exchanger can cause problems in the heater. You need to check it properly.

Gas Valve: If the main gas valve opens properly, then the furnace will heat. So, you need to inspect if it doesn’t work.

High Limit Switch: The high limit switch cuts off the power supply if it gets overheated. So you need to check for proper fan rotation.

Igniter: An improper connection of the igniter can cause problems. If you feel a spark but the unit does not start then you need to check the igniter.

Ignition Control Circuit Board: If there is no spark at the time of starting the unit then you need to check the control board.

rv furnace works

Pilot Light: The pilot light is a tiny flame that lights up automatically at the time of starting the unit. It is located at the top of the furnace.

Sail Switch: The sail switch has two types; Thermal and Magnetic. You need to check the condition of both types.

Thermostat: The thermostat needs to be checked regularly. If it gets stuck, then it can cause problems in the unit.

Time Delay Relay: The time delay relay is an electronic device that provides extra protection to the unit.


RV camping is a great way to enjoy your vacations and trips with comfort. If you have a well maintained furnace then there is no need to worry about the cold. You can easily travel in cold weather with full comfort.

So keep your RV furnace safe by taking care of it. Clean the furnace regularly for troublsheooting problems. Dometic RV furnace troubleshooting will help you to get rid of these problems quickly. If the problem is not solved with the help of this article, then you can take professional help.

It is a good idea to try furnace troubleshooting before calling a technician. This will save you time and prevent unnecessary expenses.

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