Perhaps the most important comfort factor in coaches is air conditioning.  We all live in relatively tight spaces in our coaches and a well-functioning air conditioning system is important.  Since most of us are using coaches when it is sunny and warm, proper air conditioning is a must.

 

Air conditioning effectively does two things:  It dries humid air and supplies cool air.  There are many routine steps owners can take to maximize the effectiveness of air conditioning.

 

Whether your coach has rooftop air, internal air systems, dash systems or over-the-road air, or combinations of these, the basic principles are the same.

 

First and foremost, keep condenser coils and air conditioning filters clean.  This is something almost any owner can do on an ongoing basis.  Certainly as a part of an annual maintenance routine on a coach air conditioning is a big item, keeping condenser coils and filters spotless is at least a monthly self-maintenance item.  Various filter materials are available at home improvement centers which can be cut and replaced by owners.  Many of the newer materials are excellent fine particulate filters and will actually improve the quality of air in your coach.

 

Right behind on the list is a general check of the engine area, including the air conditioning clutch and any drive belts to the compressor and alternator.

 

Check the evaporator area.  Don't hesitate to take off the air inlet grill.  Keep it clean and pour some water into the drain pan to make sure there is no leak and that drainage is complete.

 

Near the condenser, check your sight gauge for proper charge and look at the condition of your blades.  Dirty, bent or broken blades require immediate attention.

 

Look carefully at the electrical system which supports your air conditioning system, especially signs of overheating connectors, tripping breakers, loose connections or corrosion; signs of rubbing, or 'hot spots.'  Repair these right away.  Check hosing.  Do you see any signs of abrasion, leakage or cracking?

 

One thing coach owners should keep in mind is that the basic colors of a coach have a lot to do with air conditioning demand.  The darker the coach, the 'hotter' the coach, as dark colors absorb heat.  Many shells and coach conversions are neutral-gray on the top; anything that is white on the top will keep air conditioning demands a little lower.

 

A not-so-obvious consideration in proper air conditioning operation is battery condition.  Many coaches use battery power for certain air conditioning applications.  Compressors are high demand electrical consumers and good, up to date deep cycle batteries are a must.  If your coach utilizes batteries for air conditioning power, they are likely the first sign of failure in proper air conditioning use.  As with any coach mechanical system, running the system at least an hour a month is a must.  Even in cases where a coach is in storage over the winter months, regular operation of the air conditioning system will avoid a major maintenance program in the spring or summer.

 

Although it is not directly related to the operations of the air conditioner, one sign of an air conditioning system maintenance problem is the condition of the unit's cover.  That's a sign that the unit itself is likely in need of some maintenance.

 

It's important to be careful when cleaning evaporator coils.  They should be sprayed in the opposite direction of regular air flow to prevent 'jamming' crud farther into the coils themselves.  Although tempting at first, put away the high pressure washer on this job.  Coils and fins are very fragile and can be easily bent or broken by improper cleaning.

 

When generally looking at the mechanical systems of air conditioners, it is a good idea to carefully view pulleys, v-belts and housings.  Do you see discoloration, excess belt wear.  Do coolant connections have any signs of discoloration or checking?

 

Keeping refigerant at proper levels is important.  If you are running on low refrigerant, the system will work 'harder' to achieve the temperatures needed for proper temperature control.  That turns into higher compressor temperatures, which can lead to oil breakdown, gasket and O-ring leaks and even shaft seal failures. 

 

By law, refrigerant leaks are required to be repaired as soon as they are discovered, as many refrigerants are toxic to the environment.  Don't even THINK about mixing refrigerants.  Properly evacuated systems which are properly prepared for changeover are a necessity.

 

A fully loaded coach (whose isn't?) contains a great deal of mass.  Wood, laminates, tiling, cabinets and all the appliances inside a coach either generate or hold a lot of heat.  Cooling down the inside of a coach to a comfortable temperature creates maximum demand for air conditioners.  If you away for the day, turn up the temperature to say, 78 or 80, to keep the units cycling and humidity down.  You will find surfaces to be relatively cool already and it won't take long to bring the coach down to a comfort level that you like.  To conserve power, turn up the temperature in the coach before you leave.  Awnings make a big difference in keeping direct sunlight out of your coach.  Larger awnings keep off more sun; being careful not to leave large awnings up if there is a threat of strong winds; smaller awnings can tolerate much higher winds without damage.

 

An important thing to remember is to fill in the warranty cards when purchasing new units and use the warranty service if needed.  Usually, the best place to have air conditioning maintenance performed is at a warranty station where parts and know-how are readily available.  This is particularly important in non-roof top air conditioning units, which may require more specialized parts.

 

Here's a Rule of Thumb from Carrier Transcold which is a basic theory for proper maintenance of your air conditioning system.  It will assist you in determining if your system is operating properly:

 

High side (discharge) pressure

 

o  Use a digital thermometer and take the condenser inlet air temperature.

o  Add 40 to this number and total

o  Convert the total temperature to a pressure, using a pressure/temperature chart

o  Compare this calculation to the actual system high side pressure.

o  The high side pressure should be +/- 10 percent.

 

Low side (suction) pressure

 

o  Use the digital themometer, take the evaporator return air temperature.

o  Subtract 30 from this number and total.

o  Convert the total temperature to a pressure, using a pressure/temperature chart.

o  Compare this calculation to the actual system low side pressure.

o  The low side pressure should be +/- 5 percent.

 

There are a host of other factors which may affect the above readings, and are provided simply as a guide.

 

As with any complex system in a coach, air conditioning modification and regular maintenance must be performed by a qualified service professional.  Simple knowledge of the air conditioning system on your coach and regular maintenance and inspection by an owner goes a long way toward making coach ownership a lot more comfortable and fun.

 

Being familiar with your air conditioning systems also allows you to more directly explain a problem to technician, saving time and expense on the road.

 

Stay cool and enjoy your warm weather motoring experience.