Every RV has one or more Air Conditioners that helps keep it cool.   They do differ from household A/C units in a few ways, but just like household units, they do require some maintenance.  Below we will take you through the operation, maintenance and some diagnostic tips on a Dometic RV Air Conditioner.


Dometic RV Air Conditioner Operation and Maintenance


TABLE OF CONTENTS


Operation

  • FAN MODE
    • Pushing the mode button will bring you into FAN Mode.   Pushing the FAN button will allow you to choose the fan speed for the unit. HI/LOW.
    • If you stay in the FAN mode it will operate just the fan and the A/C unit will circulate Air on HI or LOW, but it will not cool the air.
  • COOL MODE
    • Pressing the MODE button again will bring you to COOL MODE showing you a snowflake in the bottom corner.  Dependent on the previously chosen fan setting will decide if the fan will run all the time on HI or LOW or AUTO.  If Auto was chosen the fan will turn off and on with the operation of the compressor.
    • It is suggested during very hot summer months that the Cool option be operated in HI fan speed only not AUTO.
    •   This will give the fins on the unit more of an opportunity to dry in between cycles of the compressor, helping to reduce the chances the A/C will freeze up and not cool your RV.
  • TEMPERATURE
    • Once the fan operation is decided in COOL mode you may use the up and down arrows to determine what you would like the target temperature to be.
  • THERMOSTAT
    • The thermostat has foam pads on the back of it that are sensitive and will break down over time if pushed hard.  The thermostat should be pushed as if it is a touch screen, lightly.  No need to mash the buttons.

Maintenance

INTERIOR MAINTENANCE

  • FILTERS
    • Interior return air filters should be cleaned regularly.   If you have animals, it should be done even more.
    • The screens are there to block any foreign objects from entering and clogging the flow of air for the A/C. If they are not cleaned regularly, it will reduce the efficiency of you unit.
    • Most filters are screens or foam filters. The screens can be cleaned with a damp cloth or a blower on an air compressor.   Foam filters can be cleaned the same way or replaced with like material.
  • MIXING DIVIDER
    • The Mixing divider above the ceiling assembly should be checked yearly to ensure no air is being mixed between the return and output sides. This can cause your A/C unit to freeze up and not cool your RV.
    • The adhesive tape around the divider will deteriorate over time and will eventually allow that air to seep through.  To remedy this issue, you will use silver HVAC tape to seal up around all the edges.  Check this yearly to ensure the tape adhesive is still holding in place and blocking the air.

EXTERIOR MAINTENANCE

  • Exterior maintenance will require you to climb onto the roof of the RV.  
  • Confirm all power and breakers are off to the A/C unit.
  • Remove the A/C shroud, being careful not to damage the coils on the back of the unit.  Once removed spray A/C coil cleaner on the coils and allow it to break down any dirt and debris in the coils.  Next rinse with low pressure water.  Do not use a jet or power option as this will damage the coils.
  • Repeat the process as necessary to rid coils of dirt and debris to allow proper airflow through the coils for operation.
  • If any of the fans or bent or damaged, you can purchase a fin comb and use it to straighten out the fins.  If the fins stay bent, it will not allow air to circulate as required for operation.

A/C Expectation of Operation

  • When in COOL mode, the difference in air temperature the blowing out will be 20 degrees lower than the actual room temperature air that is being sucked into the return vents.
  • This means if it is 100 degrees in the unit when you first turn on the A/C that the air coming out cooling the RV will be 80 degrees.  It will take some time for the RV to begin cooling to the point the room temperature is 80 degrees and the air output is 60 degrees.
  • This could take several hours depending on how high the temperature is in the unit or outside the unit.
  • This should not be confused with the A/C not working properly.

Diagnostics

  • A/C not cooling
    • If you have determined the air coming out of the vents is not 20 degrees lower than the air temperature in the room, there could be a couple of causes.
    • One cause could be that the coils are frozen.  By removing the return air vents you can examine to see if there is a sheet of ice across the coils.
    • If this situation exists, you should check the divider as suggested in the maintenance suggestion.
    • This can also be caused by the compressor not operating properly for multiple reasons.
    • In the event the coils are frozen you can turn the COOL function off and turn the FAN option to HI and allow the coils to defrost.  This will sometimes result in water dripping from the ceiling assembly.  You should lay a towel down below this to catch the water.
    • Other causes of freezing up could result from the A/C being in an area of an entry point into the unit that is constantly being opened and closed allowing warmer outside air in.  This results in a lot of condensation and can cause the unit to freeze.   Reducing in and out traffic can help with this as well.
    • If you cannot find a remedy to this, you should have one of our facilities check the unit to ensure there are no leaks in the system or other component malfunctions.
  • Fan not coming on
    • If we have our thermostat operating either the FAN or COOL option, the fan should be running.
    • In the event it is not you should check the breaker panel inside the RV to ensure there are no tripped breakers.  Also, check the power pole the RV is plugged into to ensure there are no tripped breakers there as well.
    • If this does not resolve the issue it should be brought to a service center for further diagnostic.
  • Thermostat will not come on
    • If the thermostat will not come on to operate the A/C you should check the 12-volt fuses located near the 110-breaker panel inside the RV.   Ensure the fuse is not blown.
    • Also, ensure your 12-volt system is charging and you have a good battery.

 



For a better understanding on your Dometic RV Air Conditioner 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.