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Climate Control Systems: Selling A/C Parts



Now is a perfect time to check your A/C inventory to ensure that you'll be ready when the hot weather arrives.

You might not be giving much thought to air conditioning products this time of year; however, summer will be here in just a few short months. And with it will come hot weather and a sharp jump in the demand for A/C service parts, refrigerant, compressor lubricants, leak-detection dye and related products.

The demand for A/C parts is obviously seasonal and goes lockstep with the weather. When the first heat wave hits, people seek relief and flip on their air conditioners for the first time in months. It's then that some discover that their air conditioner isn't cooling properly. The system may be low on refrigerant (usually because of a neglected leak that hasn't been repaired), or it may have other more serious problems. Either way, sooner or later the motorist has to make a choice: suffer with the heat and humidity or get their air conditioner fixed. Some may choose to tough it out and put off the needed repairs. But most succumb to the heat and realize the only way they're going to regain their cool is to have their vehicle fixed. At that point, the aftermarket gains a customer, and you get the opportunity to make a parts sale.

Though some DIYers will recharge a low A/C system, most A/C repairs are done by professional technicians. Today's automatic temperature control systems can be very complex and require a lot of expertise and special equipment like gauge sets and a scan tool to troubleshoot and repair.

Something else that prevents many DIYers from doing their own A/C repairs is the problem of evacuating the system. When an A/C system is opened up to replace a hose, compressor, condenser, receiver-drier or whatever, air and moisture get inside the plumbing. Before the system can be recharged, all of the air and moisture must be pumped out. This requires a special vacuum pump, which few DIYers have. So their only choice is to have someone else do the repairs, or take it to someone (after the repairs have been made) who can evacuate and recharge the system for them. Consequently, most of your sales opportunities will be to your professional clientele.

Over half of the A/C work being done today is being done on vehicles that are nine or more years old. Many of these jobs involve a major repair such as replacing a compressor, condenser or evaporator.

Most professionals know what it takes to fix an A/C system properly. They will decide which parts need to be replaced, which type of compressor lubricant to use, and what if any related parts should also be replaced to reduce the risk of a comeback. Even so, it doesn't hurt to prompt them or to ask if they need something else that they may have forgotten.

Let's examine compressors, for example. A compressor failure is a major catastrophe for an A/C system. It's an expensive item to replace, and it may require replacing additional parts that are also expensive.

When a compressor fails, debris may be thrown into the A/C system. Most of the junk ends up in the condenser. But if the system has a muffler on the discharge side, the muffler can also become a trap for debris that may later work loose and plug the orifice tube or damage the new compressor. Debris can even be blown backwards into the suction hose where it lies in wait to wreak havoc on a new compressor.

Flushing may help dislodge some of the debris and other contaminants. Most experienced technicians know the only sure-fire way to prevent a repeat compressor failure is to replace parts that cannot be successfully flushed like parallel flow condensers and mufflers. Replacing these parts is the only way to guarantee trouble-free operation.

Most technicians will also replace the orifice tube and the accumulator or receiver-drier. The orifice tube meters the refrigerant as it enters the evaporator. If the tube plugs up, it can block the circulation of refrigerant and lubricant. This will cause a loss of cooling and may also cause the compressor to fail. The accumulator or receiver-driver contains a bag of moisture-absorbing desiccant that is the system's only protection against contamination. If the desiccant becomes saturated, it can't prevent moisture from forming acids and sludge in the system.

Many technicians also install an in-line filter as well as a filter screen in the suction hose outlet following a compressor failure. These parts provide protection against any contaminants that may be hiding in the system and will stop any debris before it can cause further trouble.

Equally important to preventing repeat compressor failures is using the correct lubricant. Years ago when only R-12 A/C systems were used, mineral oil was the only compressor lubricant that was required. Today with R-134a A/C systems and a steadily declining number of R-12 systems, a broader spectrum of lubricants is required. Older R-12 systems still need mineral-based compressor oil, but those that have been retrofitted to R-134a require wither a POE ester oil or a particular viscosity of PAG oil. Mineral oil is not compatible with R-134a, so POE or PAG must be used.

The aftermarket has favored POE because it's a more "universal" type of lubricant that is compatible with both R-12 and R-134a and works well in most compressors. But most vehicle manufacturers specify a particular viscosity of PAG for their compressors.

The best advice here is to follow the lubrication recommendations of the vehicle manufacturer or compressor supplier.

The demand for retrofit has peaked, and it is now declining according to most sources in the A/C service industry. The demand for retrofit kits is also down because most technicians have figured out that changing an older R-12 system over to R-134a isn't as difficult as it first appeared. Most only buy the individual parts needed

For a simple retrofit, some might only need a few cans of R-134a refrigerant and a can of POE oil. On some vehicles, the o-rings and accumulator or receiver-drier should also be changed if the original parts are not compatible with R-134a. And on some, the compressor itself won't work because of: seal incompatibility; or it isn't strong enough to handle the higher operating pressures of R-134a. For these kinds of applications, a retrofit usually isn't done unless the original compressor has failed and needs replaced.

Other parts that may also have to be replaced include the orifice tube and/or condenser. A variable orifice tube can improve low-speed cooling performance, and some vehicles may require a larger or more efficient condenser to provide good cooling performance when retrofitted to R-134a.

To maintain a preset air temperature, ATC systems use one or more interior air temperature sensors, an ambient (outside) air temperature sensor and possibly one or two sunload sensors. These sensors are critical to the operation of the system. If one fails, it can prevent the system from cooling or heating properly.

Interior air temperature sensors are usually simple two-wire thermistors that change resistance with temperature, but some are infrared sensors that detect heat from the vehicle's occupants. The interior air temperature sensors may be located in the ATC control head, instrument panel, overhead console or even the seats.

The ambient air temperature sensor that monitors the outside temperature is located outside the passenger compartment often at the base of the windshield or in the front of the vehicle. Many ATC systems only look at the ambient temperature when the vehicle is first started or when it's moving.

Sunload sensors measure the intensity of sunlight that's shining on the vehicle, are usually located on the top of the dash and have a small photo diode inside a white plastic dome. Sunload sensors are supplied a reference voltage by the ATC module, and pass current when the light intensity reaches a certain threshold.

Some ATC systems have additional temperature sensors located on the evaporator and/or compressor to prevent evaporator icing and to regulate the operation of the compressor. Some Asian vehicles also have duct temperature sensors and heater core temperature sensors to further refine temperature control. These are usually found on the dual-zone ATC systems.

Though temperature and sunload sensors are pretty reliable, any of these sensors may fail at any time. Some are available as aftermarket parts, so check with your A/C parts supplier before you refer a customer back to the new car dealer.

Another item that affects cooling performance and may have to be replaced is air door control motors. These include the little vacuum and electric motors that position the air blend doors inside the HVAC unit. Newer vehicles tend to use mostly electric motors, while the older ones use vacuum motors. Some electric motors have a position sensor or separate feedback circuit to keep the ATC control module informed about their position. Vacuum motors and some electric motors are available through aftermarket suppliers, but many of the newer parts are only available through a new car dealer.

One thing most shops that do A/C work today need is leak detection dye. Many technicians prefer dye over electronic leak detectors because they say it does a better job of revealing leaks. Many shops add a dose of dye when they recharge a vehicle to make leaks easier to find next time around.

There are also "sealer" additives that can be added to the A/C system to plug small leaks. Pinhole leaks in an evaporator, hose or seal can sometimes be sealed with such a product. But some technicians question the effectiveness of sealers, while others question the potential risk for causing additional problems such as plugging up the orifice tube. The best way to stop the loss of refrigerant from an A/C system is to pinpoint the leak and replace the leaky hose, seal or other part. But parts like evaporators are hard to reach and expensive to replace, so a sealer may provide a more cost-effective solution to a customer's immediate problem.

Every shop that does A/C work must have approved refrigerant recovery equipment. Venting refrigerant is illegal. Shops also need equipment that can identify the type of refrigerant in a system to reduce the risk of cross-contamination. Service gauges, leak detection equipment (electronic or ultraviolet), evacuation pump and special hand tools for removing and installing compressor seals are also "must haves" for today's A/C technicians. So too is a scan tool for reading ATC system diagnostic trouble codes.

Browse some A/C equipment catalogs, and be familiar with what's available. Many shops may need to upgrade outdated equipment or buy new equipment. A/C service is a growing opportunity, so why not be on the leading edge? Be familiar with the parts and equipment your customers need, and you'll see more A/C sales as a result.

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