RETROFIT - NOW OR LATER?
Currently, there is no law or regulation stating that a vehicle must be converted to refrigerant R134a. However, the R12 supply is running out, so if a major repair is required on a R12 system it is in the customers' best interest to convert to the R134a refrigerant.

Notice: The following answers to frequently asked questions, are meant to be a reference when seeking the services of a certified A/C Service Technician, and are not to be used as a guide or endorsement for servicing your own A/C system.

1. Why do I need to use an exact amount of Freon?
2. What is a "Liquid Charge", and why is it dangerous?
3. What causes clutch failure?
4. What causes compressor failure?
5. Why should I use R134a refrigerant?
6. What does humidity have to do with my air conditioner?
7. Where does the "High Side" begin?
8. Just what is this "Black Death"?
9. What exactly does a drier dry?
10. What is your position on flushing?
11. What about system leaks?
12. What does all this A/C jargon mean?
13. What is a ton of refrigeration?
14. How many different condensers are there, and which can be flushed?
15. What causes excessive clutch cycling?
16. Why should I worry about ESD?
17. Can compressors take all that heat?
18. Does it matter what oil I use?
19. What are the "Three laws of air conditioning"?
20. What should be done when installing a compressor?
21. How does an automotive A/C system work?
22. What about "Low Air flow"?
23. My clutch (or switch) does not function, what can I do?
24. Is a little moisture in the system really such a big deal?
25. What are the basic A/C systems?
26. How are clutch cycling switches different?
27. Are your compressors compatible with R12 or R134a?

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Why do I need to use and exact amount of Freon?
Today's A/C systems use smaller amounts of Freon. No longer is it 2 to 4 lbs, but rather 18 to 38 oz. With tight compressor tolerances and lubricant mixed with the Freon, the mixture must be just right to enter the compressor as a mist. Wrong mixtures will either under lubricate or slug the compressor causing premature failures. You don't know how much liquid Freon is in a system so you should recover the old Freon, evacuate and add the correct charge. Always check the OEM spec for the correct charge.

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What is a "Liquid Charge", and why is it dangerous?
A "Liquid Charge" is any charging of the A/C system using Freon which enters the A/C system in a liquid state as opposed to a gaseous or Vapor state.

Warning! Charge A/C System with Freon as Vapor, not Liquid!
If a charging hose is long enough you might get away with using liquid refrigerant because the liquid will partially change to a gas in the hose. The odds are not in your favor. More often you will freeze and shatter the compressors valves when the refrigerant hits the valves as a liquid. This happens in mere seconds, which is why we recommend charging the A/C system with the engine off.

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What causes clutch failure?
Some common causes for clutch failure:

1. Bearing failure.
2. Air Gap: Between the outer plate (hub) and the belt/rotor (.016 -. 030 inch) Note! Air gap varies with compressor type - check OEM specs.
3. Shorted Coil - Due to improper polarity or weak/burnt winding.
4. Low voltage at coil will cause coil to overheat due to slippage.
5. Locked Compressor: Excessive discharge pressure - Check for restricted condensers, receiver/driers or an oil over charge
6. Belt is wrong type, wrong size, miss-aligned or loose.

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What causes compressor failure?
Some common causes for compressor failures are:

LACK OF USE:
Compressors not run regularly will be starved for lubrication when they are turned on. This causes excessive ware until the oil again reaches the compressor. It's best to use the A/C once a week for a few minutes.

FAILURE TO FLUSH SYSTEM:
Compressors and hoses wear causing bits and pieces to mix with the oil. This sludge gets into the compressor and can cause it to seize. Failure to properly flush or using flush that leaves a residue is a primary cause of failure.

EXCESSIVE HIGH OR LOW PRESSURE:
Condenser fans can quit due to bad connections or defective motor windings that get too hot. This creates excessive head pressure and heat that can lock up or damage a compressor. Loose connections at the coil can cause high resistance and low voltage causing clutch slippage. Low refrigerant charge will cause lack of lubrication getting to the compressor. Painting condensers will insulate them from efficiently removing heat and increase head pressure in the compressor.

IMPROPER FREON OR OIL CHARGE:
Compressors manufactured after 1990 have smaller capacity, therefore use less refrigerant and oil and are extremely sensitive to inadequate amounts of oil. The wrong type of oil may break down in high heat conditions. R134a systems are more sensitive to lubrication than R12 systems. An over charge of oil can clog the condenser, the orifice tube or expansion valve and starve the compressor of oil. R12 systems use mineral oil and R134a systems use PAG or Double End Capped PAG Oil (always check the OEM specs)

REFRIGERANT BLENDS
They can affect seals and O-rings, causing them to leak, swell or otherwise deteriorate and it can happen relatively quick.

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Why should I use R134a refrigerant?
R12 has the ozone depleting chemical chlorine in it and has been replaced with a refrigerant known as R134a. A boiling fluid absorbs heat and changes its state to a vapor. The expanding vapor/gas has a lower pressure than the liquid and therefore lower temperature. For heated air to be absorbed it must transfer to a cooler surface. The trick is to find a liquid that boils at such a low temperature that the vapor is cold enough to absorb the amount of heat generated inside an automobile. Freon-12 boils at -22º F and its expanding vapor, in the evaporator core, absorbs the heated air circulating around it. Freon-134a boils at about the same temperature as R12 and therefore is a good replacement.

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What does humidity have to do with my air conditioner?
You're A/C unit works to remove heat from the passenger area and in doing so it also removes moisture. We are most comfortable when the relative humidity is closer to 20 percent than 90 percent, therefore the A/C system expends most of its effort wringing moister out of the air. This is what air conditioning is all about - conditioning the air. It's important to check the condensation drain at the bottom of the evaporator. If you see clear water dripping from your car, when parked… it's a good thing…if it's from the evaporator.

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Where does the "High Side" begin?
Where ever the dam is located is the separation point. We call it a dam because it has high pressure on one side and low pressure on the other. This separator is call an Expansion Valve or an Orifice Tube. Its job is to allow only enough refrigerant through to allow gas expansion in the evaporator. By limiting the flow of gas it creates the high pressure back to the compressor.

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Just what is this "Black Death"?
Black Death, as it is known by A/C techs, is a result from the breakdown of the refrigerant-lubricant. This causes excessive wear inside the compressor and the excessive ware causes a black residue that is actually a combination of solder flux from the condenser and aluminum shavings from the old compressor. When this goop cools, it hardens in the condenser. Repeated flushing will not remove it, however, when the system is charged and running it liquefies, flows out into the liquid line and clogs the orifice tube. With less refrigerant flowing, past the orifice tube, the compressor is starved of lubricant and will lock up. The only answer is to replace the condenser.

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What exactly does a Drier dry?
It's not the freon!! It's the oil in the refrigerant that absorbs moisture and holds debris in the system. Replacing the drier or accumulator, in addition to evacuation, will assure better performance.

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What is your position on flushing?
Oil, sludge and debris that is left in the system can clog the condenser, orifice tube or expansion valve and damage the compressor. Flushing can remove excess oil and debris from previous services. You do not want to add yet another charge of oil while leaving an unknown amounts of oil in the system.

Caution!

Only flush a condenser that capable of being flushed. The answer to question #14 deals with this problem in greater detail.

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What about system leaks?
At one time Freon was cheap and a 2oz. per year leak was acceptable in a 4-5 lb. System. Today systems are smaller and 1/2oz makes a big difference in performance. Good halogen leak detectors will show most system leaks, under static conditions, however some will leak only when the system is in operation. This is where the insertion of a florescent dye can help find the leak. Note, to see the dye stain you need a UV lamp and the leak has to be where the light can reach it. Most car manufactures approve the use of trace dyes and some OEM's have been inserting trace dyes on the assembly line. Dye can be inserted either when charging or when the system is charged. The amount of dye used is less than 1/3 oz and remains in the system even if the total charge is lost. The dye stains the oil not the Freon and only flushing will remove it.

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