Tips on Care and Maintenance of the RV Air Conditioner

• Bernhart says:  Clean the filters at least every two weeks when the air conditioner is in operation. Running the unit with dirty or clogged filters will decrease the flow of air across the cooling (evaporator) coil, potentially causing the coil to freeze up. If the air conditioner is running for long periods of time with dirty/clogged filters, a potentially expensive cleaning of the evaporator coil by qualified service personnel may be necessary.
• Bernhart says:  If your motor has oil ports, we recommend using SAE 30 weight non-detergent oil. The motor requires only 1-2 drops of oil per year. DO NOT OVER OIL. The oil ports will be visible on the fan motor with the unit's plastic cover (shroud) removed.
• Bernhart says:  Clean the outside (condenser) coil at least once a year. Blow out any debris which may have collected on the coil. Since the A/C fan pulls air in through the back of the coil and exhausts it from the sides of the shroud, it is best to blow compressed air through the coil from the inside out. You may also wash this coil with water if you choose to do so. Please remember to disconnect all power to the vehicle/air conditioner first.
• Finally, Bernhart says you should inspect the air conditioner and its housing. If the housing is loose or cracked, the seal that prevents water and moisture to enter the RV could be damaged. You should also look at the condenser fins and make sure none of them are bent or damaged. Air conditioner fins aren't typically replaceable, and many times they cost as much as a new air conditioner. You should also wash the exterior of the air conditioner and remove any bugs, road tar, or other debris on the exterior of the unit.

More Advanced Topics:  Understanding How the Relay Works:

So what is a relay? A relay is defined as an electromagnetic mechanism moved by a small electrical
current  in a control circuit (12VDC in this case). How does this relay work? As this mechanism
moves back and forth in the relay it will open or close a set of contacts capable of carrying high
voltage and (115VAC in this case). All of our control circuit relays are normally open and the
contacts close as power from the thermostat is applied.  The 115VAC power to the compressor is interrupted
by a set of normally open contacts on the relay. In order for these contacts to close 12VDC must be applied by the
wall thermostat to the relay coil. When the thermostat switch is placed in the cool position 12VDC(+) travels from
the thermostat red wire to the thermostat yellow (Y) wire and then to the relay coil. When the coil is activated an
electromagnet inside the relay will pull the contacts closed.  The 115VAC will now operate the compressor until the
thermostat opens or the system switch is turned to the off position. The entire control circuit for the A/C  Heating
system would include the rest of the thermostat functions and possibly 2  or 3 more relays. In addition to the compressor relay you would need a separate relay for Low Fan, one for High  Fan, and possibly one for Heat, if a heat pump or electric heating element is used.

Thermostat Location:

All of the air conditioning functions are controlled by the wall mounted thermostat.  These
thermostats utilize a 12 VDC electrical circuit which is supplied by the vehicle manufacture or the
installer of the A/C unit. Most of the thermostats provided by Recreation Vehicle Products 
are combination (Heat / Cool) thermostats. These thermostats are capable of operating both the
roof top air conditioner and any furnace with a 12 VDC control circuit. Thermostats are really nothing more than
temperature controlled switches. When the need for Cooling or Heating exists the thermostat sends a 12VDC(+)
signal to the control relays or a P.C. board which in turn energizes the air conditioner components or the furnace.
Thermostats are very sensitive instruments. For accurate temperature control and comfort the following
considerations for thermostat locations should be taken into account:
1. Locate the thermostat on an inside wall about five foot above the floor. Pick a dry area where
air circulation is good. The thermostat should be mounted within a reasonable distance from
the appliance the thermostat will control. This will assure a more accurate temperature
relationship between the thermostat and the appliance the thermostat will control.
2. Do not install the thermostat where there are unusual heating conditions; such as direct
sunlight, heat producing appliances (television, radio, wall lamp, etc.); or a furnace or air
conditioner supply register.
3. When installing or servicing these thermostats the technician should take all necessary
precautions not to short any positive wire to ground. Permanent damage to the thermostat
may occur. Make sure all connections are good and tight. Loose connections may cause
relay chattering which leads to welded relay contacts on air conditioner printed circuit
boards.

Remember, you must first verify the 115VAC power source to the Air Conditioner Control
Box Assembly. If the 115VAC power source is NOT present, all of the Air Conditioner functions will
be dead and power must be restored to continue. 115VAC power must be present to the Circuit
Board if any one of the Air Conditioner functions are working.


AT ANY TIME that you use a generator to run any load, be sure to have all loads turned off when you start the generator. And when you're ready to shut the generator down, FIRST turn off all loads.

Two air conditioners?  Some big RVs have two air conditioners--and your rig will wired for 50 amp service. If you stay at an RV Park where you can't get a 50 amp hookup, you'll be using an adapter to plug in your rig. Don't try to run both your air condioners at once on this lashup--you'll only blow breakers and cause problems all around. An optional switching system you can have installed can overcome this problem--but it only serves to automatically swap between air conditioner units.

Thank you for visiting the Bruce Bernhart RV Websites!

Be sure to visit the other Bruce Bernhart RV Websites and Blogs:

Solar power for your RV

The care and feeding of your RV battery

The sport of "geocaching" and RV refrigeration basics

The basics of RV power inversion

RV travel tips and tire care

Advanced discussion on power inversion

Tips on buying a house battery and cold weather maintenance

RV Insurance

Buying the right generator for your RV and portable power

RV television reception options

Care and maintenance of the RV air conditioner

Emerald Isle

RV long-term supplies and weight considerations

RV trip insurance- advanced Topics

RV battery types and winter charging considerations

Deep cycle battery basics

Also, check out the Bruce Bernhart Mandolin Websites:

Bruce Bernhart mandolin rock tabs

Bruce Bernhart mandolin lessons- common scales

Bruce Bernhart on buying and setting up your new mandolin

Bruce Bernhart mandolin lessons- tuning

Bruce Bernhart mandolin lessons- chord patterns

Bruce Bernhart on mandolin history and basic chord structures

Bruce Bernhart on string and saddle adjustment

Bruce Bernhart more tuning tips and whole/half steps

Bruce Bernhart on more chord patterns

Bruce Bernhart on the mandolin family

Bruce Bernhart on mandolin bluegrass chords and patterns

Bruce Bernhart on temperature considerations

Bruce Bernhart lessson on mandolin flats and sharps

Bruce Bernhart lesson on scales, circle of 5ths and meter

Bruce Bernhart on triads, gears

Bruce Bernhart mandolin chord diagrams

Bruce Bernhart on modern emergence of the mandolin

Bruce Bernhart on simple chords

Bruce Bernhart on whole and half-note steps on the mandolin

Bruce Bernhart mandolin practice excercises

Bruce Bernhart on playing waltzes

Bruce Bernhart on majors, minors and sevenths