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1. Why do
I need to use an exact amount of
Freon? |
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2. What
is a "Liquid Charge", and why is it
dangerous? |
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3. What
causes clutch failure? |
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4. What
causes compressor failure? |
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5. Why
should I use R134a refrigerant? |
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6. What
does humidity have to do with my air
conditioner? |
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7. Where
does the "High Side" begin? |
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8. Just
what is this "Black Death"? |
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9. What
exactly does a drier dry? |
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10. What
is your position on flushing? |
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11. What
about system leaks? |
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12. What
does all this A/C jargon mean? |
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13. What
is a ton of refrigeration? |
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14. How
many different condensers are there, and which can be
flushed? |
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15. What
causes excessive clutch cycling? |
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16. Why
should I worry about ESD? |
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17. Can
compressors take all that heat? |
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18. Does
it matter what oil I use? |
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19. What
are the "Three laws of air
conditioning"? |
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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? |
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25. What
are the basic A/C systems? |
|
26. How
are clutch cycling switches
different? |
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27. Are
your compressors compatible with R12 or
R134a? |
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28. Do
your compressors come with a clutch? I don't see any
mention of the clutch on the details
page. |
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29. Is
there a core charge? If so, how
much? |
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30. How
long is the warranty on your
compressors? |
|
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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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What does all this A/C
jargon mean?
Glossary of Terms:
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 through
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
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Replace manifold
sealing washers or O-rings
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Use a Vacuum
Pump (20+ minutes) to remove moisture.
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Add the proper
amount and type of oil. Check OEM spec
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Rotate
compressor hub 12 times to oil the shaft seal
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Place a strong
external airflow into the condenser
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Check OEM
specifications for correct refrigerant charge
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Charge with
VAPOR refrigerant and with A/C and engine off.
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Do a leak test
and check voltage at clutch coil
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Check belt
tension and alignment
-
Check system
operation at 1500 RPM and mid-blower speed
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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
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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.
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Do your compressors
come with a clutch?
All of our
compressors come complete with the clutch assembly. No
compressor leaves our facility without the clutch
assembly attached and fully tested.
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Is there a core charge?
If so, how much?
As
the compressor market is so volatile, we do not charge
a core charge. This allows us to further pass the
savings to our customers. The price you see on the
website is the outright price (+ Shipping & or
Tax). In the event you purchase one of the harder to
find units, we will send a prepaid UPS return tag with
the compressor. If your old unit is in rebuild-able
condition, we will issue a credit back to your method
of purchase based on market value at the
time.
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How long is the
warranty on your compressors?
The short answer:
12 Months. However, the actual term of the warranty
varies depending on the units application. (i.e.,
Heavy Duty application compressors are only warranted
for a period of 6 months). Please refer to our
Warranty Policy (Button on the left) for further
details.
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