ACCUMULATOR: stores & filters Freon (on Low side of system)
BTU: British thermal unit
AMBIENT AIR: outside air
CAPILLARY TUBE: gas filled temperature-sensing tube
CCOT: clutch cycling orifice tube that replaces the TXV
CLUTCH CYCLE SWITCH: evaporator temp controlled switch that cycles clutch
COMPRESSOR: pump that moves the refrigerant.
CONDENSER: heat exchanger-removes heat from refrig
DISCHARGE LINE: compressor outlet line
DRIER: filters refrigerant (located on High side of system)
EPA: Environmental Protection Agency
ESD: Electrostatic Discharge
EVAPORATOR: heat exchanger-removes heat from air
HEAT: anything above absolute zero has heat
HEAT EXCHANGER: device for transferring heat
LIQUID LINE: moves high-pressure liquid through system
MANIFOLD: connects suction & discharge lines to compressor
PAG: Polyalkylene glycol (lub used with R134a refrigerant)
PROM: Programmable Read Only Memory - use in computers
SUCTION LINE: between evaporator outlet and compressor
TXV: Thermostatic Expansion Valve - maintains evaporator
 

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What is a ton of refrigeration?
One Ton of refrigeration is defined as amount of heat (288000 Btu's) required to cause a change in state of one ton of ice to one ton of water at 32 degs. F in 24 hours.
A/C units are rated by Btu/hour ratings. A one ton unit is rated as 12000 Btu's (288000/24) The average factory installed auto A/C unit is rated at 1-3/4 ton.

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How many different condensers are there, and which can be flushed?
R134a condensers have more fins/inch than R12 condensers and their fin diameters are smaller.( 6mm)

TUBE and FIN - Oldest industry standard, 3/8-inch diameter round tube condenser. Ok, for R12 but not recommended for R134a. This type of condenser is flushable.

6 mm PICCOLO multi-flow: smaller, lightweight and more efficient than 3/8-inch tube and fin and serpentine. Used in many domestic OE applications. This type of condenser is flushable.

SERPENTINE: All aluminum, more efficient than tube and fin, used on smaller imports where space is limited. This type of condenser is not easily flushed, replacement is recommended.

PARALLEL FLOW: all aluminum, this efficient design breaks up flow into tiny streams that give up heat more rapidly. This type of condenser is not flushable, replacement only!

PARALLEL FLOW with SUB Condenser. Oval tube multi-flow and sub-condenser stacked up. Refrigerant flows hrough the multi-flow into the drier (called a modulator) then continues as a liquid into the sub-condenser. This type of condenser is not flushable, replacement only!

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What causes excessive clutch cycling?
It's common to assume low refrigerant is the cause for excessive clutch cycling and this often leads to adding refrigerant and thereby overcharging the system. Most vehicles have a compressor clutch cutout strategy based on an engine coolant temperature of 220 - 240 degs F. The vehicles computer relies on a coolant temperature sensor to provide the signal for the compressor clutch decision and if the sensor reads too high the clutch will cycle off. Cooling systems with a 50-50 anti-freeze mix and the proper radiator cap should boil at around 275 degs, so the system may not be boiling when the compressor cuts out. Check the actual coolant mix and temperature by using an Infrared thermometer to check coolant temperature and a Scan Tester to tell you what temperature the sensor is actually signaling to the computer.

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Why should I worry about ESD?
During the testing and repair of computer controlled vehicles we come in contact with components that may be damaged by ESD or static electricity. When installing new electronic components, the part itself may have developed a charge from contact with the package during handling; therefore you need to ground yourself to the body ground of the vehicle. This is easily done by using a wrist strap that is available at most electronic supply stores (Radio Shack)

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Can compressors take all that heat?
A compressor can take the heat, but if there's a condenser airflow problem, overcharge, poor lubrication, restriction, etc., the temperature can greatly rise and cause the compressor to seize. Some vehicles have compressors mounted low in the engine compartment and due to poor airflow the compressor can overheat and fail.

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Does it matter what oil I use?
The moving parts of a compressor must be lubricated during operation. The oil is absorbed into the refrigerant that carries it through the compressor as a mist. An oil over/under charge can damage the compressor. Compatibility of refrigerant oil is determined by its ability to remain oil when mixed with the refrigerant and not become separated by a chemical reaction. R12 systems use a non-foaming sulfur-free grade of mineral oil (YN-9) formulated for that refrigerant and cannot be used in R134a systems. R134a systems use either synthetic oil (PAG) YN-12 or Double End Capped PAG oil.

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What are the "Three laws of Air Conditioning"?
Everything has heat except at absolute zero (-460 degs. F)
LAW I: to refrigerate is to remove heat - the absence of heat is cold.
LAW II: heat is ready to pass to anything that has less heat - nothing can stop the flow, you can only slow it down
LAW III: if a change of state is to take place there must be a transfer of heat - If a liquid is to change to a gas it must take on heat.

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What should be done when installing a compressor?
Flush, with an approved solvent, to Clean the system*
Replace the Accumulator/Drier or Orifice tube
Replace manifold sealing washers or O-rings
Use a Vacuum Pump (20+ minutes) to remove moisture.
Add the proper amount and type of oil. Check OEM spec
Rotate compressor hub 12 times to oil the shaft seal
Place a strong external airflow into the condenser
Check OEM specifications for correct refrigerant charge
Charge with VAPOR refrigerant and with A/C and engine off.
Do a leak test and check voltage at clutch coil
Check belt tension and alignment
Check system operation at 1500 RPM and mid-blower speed
Use gauges to check the system pressures.
*Only if the condenser is the type that can be flushed.

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How does an automotive A/C system work?
All matter has a certain amount of heat except at absolute zero (-460º F). Ice cubes feel cool to the touch, but actually it just has less heat than your hand. Heat is transferring from your hand to the ice cube. This is the principle behind how an A/C cools the air in a car. Heated air is circulated across a gas filled evaporator and is transferred to the refrigerant gas making the air less hot. The heat-laden refrigerant then is drawn into the compressor, is super heated by compression and forced through the condenser where the cooler outside air takes the heat from the refrigerant. Its next stop is the expansion device (TXV or Orifice tube), which meters refrigerant into the evaporator where it expands into a gas and it starts over again.

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What about "Low Air Flow"?
The complaint: "it used to blow harder". Things to check are:
Low blower motor voltage due to a poor ground
Blower wheel loose on motor shaft
Defective blower relay
Air leak or obstruction in air duct system
Air mode door directing some of the flow to the heater outlet
Icing evaporator core due to condensation.
Debris in evaporator housing that blocks air circulation.
Obstruction at the air return

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My clutch (or switch) does not function, what can I do?
Electronic circuits are sensitive to voltage drops and operate in narrow voltage ranges. Many connectors have small spade or pin type connections and are engineered to have near zero resistance. If the connection is even slightly loose it will affect the voltage. What may seem to be a defective component could be a bad connector. The problem may be corrosion and careful brushing or using an electrical contact cleaner may cure it. Many OEM harness connectors are available as replacement parts.

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Is a little moisture in the system really such a big deal?
Moisture causes internal icing that obstructs the orifice tube or expansion valve. This can create excessive high pressures and low cooling. The A/C system is a closed loop system so why does it need a Drier to remove moisture? Here's how moisture gets into the system. Refrigerant charged through service hoses not evacuated after being connected to the system will have air and moisture in them. Hoses left uncapped while replacing components allows moisture to enter. Refrigerant oil is hydroscopic (water absorbing like a sponge) and left uncapped will have moisture in it. Recycling machines with old filters will not remove moisture from incoming refrigerant. Condensation created when the Low side of the system gets cold and then warms up when the system is turned off is absorbed into the system through the hoses. Systems low on freon will pull moisture into the system when they go into a partial vacuum.

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What are the basic A/C systems?
ORIFICE TUBE SYSTEM
Orifice tube systems use an Accumulator located in the Low side of the system

EXPANSION VALVE SYSTEM
TXV systems use a Drier located in the High side of the system.

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How are clutch cycling switches different?
The clutch cycling switch for R134a vehicles has been calibrated for the slightly higher pressure of R134a. The threads, on the switch fitting, have been changed to metric to avoid connecting to a R12 system.

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Are your compressors compatible with R12 or R134a refrigerant?
All of our compressors are remanufactured with retrofitting in mind. Each compressor is remanufactured with Nitrile or HNBR seals which allow the compressor to be installed in either R12 or R134a refrigerant systems.