Most RV’s have a gas furnace to help keep the unit warm in cold temperatures.   This furnace will operated using the propane tanks as a fuel source.  A gas leak check is recommended yearly for the RV gas system before operating the appliances.  You should also ensure all of your safety devices are up to date and operational. Below we will take you through the operation, maintenance and some diagnostic tips on a Dometic Gas Furnace.  Dometic has 2 different installs, one where the cover is removable and the furnace is accessible from the outside, the other is only accessible from the inside of the RV.


 

Dometic RV Gas Furnace Operation and Maintenance


TABLE OF CONTENTS


Components

  • Exhaust
    • The exhaust is where the burn off from the gas will come out.  This exhaust cover will be hot when the furnace is operating, and contact should be avoided. 
  • Reset Switch
    • This is a 12-volt breaker switch that will trip in the event the furnace has a fault.
    • On the models that are not accessible through the door on the outside, the switch is mounted on the interior of the RV, generally on the outside of the heat shield of the furnace.
  • Control Board
    • The control board sends the signals to initiate the furnace operation based on the initiation on the thermostat.

  • Gas Valve
    • The gas valve will receive a signal from the board to open.  This allows the propane into the chamber and the igniter will light the fuel to begin heating.

  • Fan Motor
    • The fan motor will initiate before the source is ignited and also run for a period of time after the burner has turned off in order to cool the chamber.
  • Limit Switch
    • There are several limit switches on the fan blower housing that lets the board know the fan is operational. 

 

Operation

  • Gas bottles must have propane and the valves will need to be on.
  • The thermostat will be turned to heat, and the target temperature will be set.
  • The furnace blower will then begin to spin and you will hear a ticking noise indicating it is trying to ignite the fuel source.
  • Furnace will operate until the temperature is reached and the burner will turn off.  The fan will continue to run until the chamber has cooled off.


Diagnostics

  • LED Light Diagnostics
    • In the event the furnace is not operating properly you can check for the sequence of lights to indicate the fault.  This is good information to have when booking an appointment for diagnostics.
    • 1 w/ 3 sec pause : Air Flow / Limit Fault
    • 2 w/ 3 sec pause : Flame Sense Fault
    • 3 w/ 3 sec pause : Ignition Lockout Fault
    • Steady on, no flashing : Internal Control Failure

  • Power
    • The only power needed for the furnace is 12 volts.   If there is ever an issue where the furnace or thermostat will not turn on, check the 12 volt fuse panel near the breakers to ensure there are no blown fuses.  Also, ensure your charging system is operating properly and you have a good battery.
  • Air in the System
    • If the camper was stored and the tanks were shut off or you have just replaced the tanks, it is common for air to be in the lines.  This will result in the furnace attempting to ignite (hear the clicking noise), but fail to do so and shut down after 3 attempts.
    • If this happens, you should go to your stove top and turn on and light one of the burners.  Allowing the air to bleed out of the gas system.  You should have a crisp blue flame.  In the event, you have a poppy orange flame or still no ignition, continue to bleed the air out while trying to ignite and allow it to burn until a crisp blue flame is reached.
    • Once this is completed reinitiate your furnace at the thermostat by turning it off then on and allow the furnace to try to light again.
    • Air in the system after it has been shut off or tanks have been changed is the most common issue.
  • Diagnostics
    • Check sealant around mounting of the furnace.   If only the exhaust is on the outside wall you will need to check sealant there as well.  You are looking for any sealant cracking or peeling that will need to be resealed.
    • If you have the model that has the black cover from the outside you want to ensure the gasket is in good shape and not deteriorating.
    • Blow out the exhaust tube and ensure there is no insect nests blocking the flow of air.  This can be done with a blower connection on the end of a compressed air line.


 

For a better understanding of your Dometic RV Gas Furnace Operation and Maintenance, check out this video: 

This content is not a legal standard or regulation, and does not create any new legal obligation.  It is advisory in nature, informational in content, and is intended to assist and educate consumers in the use and enjoyment of their recreational vehicles.  Great American RV Superstores does not hereby make any warranty, express or implied, and does not assume any liability with respect to the use of, or damages resulting from the use of any information, method or process included in this content.