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Old 17-04-2017, 05:48 PM
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Default Check Your Car's Air Conditioning System



How to Check Your Car's Air Conditioning System

You should check your car's A/C system BEFORE hot weather arrives to make sure it is working properly and blowing cold air. see the following tips on how to check your car's air conditioning system

Note: Always be extremely careful any time you are under the hood while the engine is running. Stay away from all rotating components with your hands, clothing, and hair, and always wear eye protection around a running engine.

1. With the engine running, does the compressor clutch engage when the A/C is switched on? If it does not, this usually indicates a low (or empty) refrigerant condition, or an electrical problem. Also, listen for rapid clicking or cycling noises at the compressor when the A/C is switched on. If this is happening, it could also indicate low refrigerant or some other problems. Have it checked by your service technician. (Note: Some A/C systems prevent compressor clutch engagement in low temperatures, typically at or below 40� F.)


2. Is the A/C system blowing cold air? Luke warm air or air that is barely cooled at all could indicate a low refrigerant charge in the A/C system. Pressure gauges can be used to check the refrigerant charge. If low, add refrigerant to bring the system up to full charge. See How To Recharge Your Car's Air Conditioner for more information on how to add refrigerant.


3. With the engine running and the A/C switched off, listen for knocking or rumbling sounds in the vicinity of the compressor. These could indicate a failing compressor clutch, and/or loose mounting hardware.


4. Are A/C component mounting bolts in place and tightly secured? Nothing loose or rattling around?


5. Are caps installed on the A/C system service ports? This keeps out dirt, and also provides a seal for refrigerant.


6. Check all belts for cracks, wear, and glazing. Have them replaced at the first sign of any of these conditions. Also, check for belts that vibrate while the engine is running and the A/C is on. This may indicate a belt that needs to be tightened, or a defective automatic belt tensioner.


7. Examine all A/C and cooling system hoses for cuts, abrasion, weak spots, and signs of leakage. Leakage from A/C system hoses is often indicated by an accumulation of dirt and oil, particularly at connections and fittings.


8. Make sure the condenser (in front of the radiator) is free of any obstructions, such as leaves or insects. This could reduce airflow, resulting in reduced A/C performance. You can rinse the condenser clean with a garden hose.




Gauge test info


Last edited by Holly Goodhead; 19-04-2017 at 08:55 PM.
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Old 17-04-2017, 06:05 PM
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How To Recharge Your Car's Air Conditioner

LOW REFRIGERANT






If your air conditioner is not cooling well because the system is low on refrigerant, recharging the system with refrigerant should restore normal operation. This can usually be done with a few cans of refrigerant and a simple service hose connection.

A/C RECHARGING PRECAUTIONS

First, wear safety glasses to protect your eyes. Also avoid skin contact with refrigerant. The chilling effect of spilled refrigerant can cause instant frostbite on bare skin or eyes!

WHAT TYPE OF REFRIGERANT?

Next, you need to figure out what type of refrigerant your vehicle requires:
On 1995 and newer passenger cars and light trucks, the correct refrigerant is R134a. DO NOT use any other type of refrigerant.

On most 1994 and older passenger cars and light trucks, the original refrigerant was R12. R12 is no longer available to do-it-yourselfers and is very expensive. When older vehicles with R12 A/C systems need refrigerant, they can be refilled with recycled R12 from other older cars (this requires taking your car to a repair shop for professional service), or with some alternative refrigerant other than R12, or with R134a (which requires certain modifications).


CAUTION: Mixing different types of refrigerants is NOT recommended. Use the same type of refrigerant that is already in the system unless you are converting an older R12 system to R134a or another refrigerant.

WARNING: Flammable refrigerants are illegal. DO NOT use any type of flammable refrigerant (propane, butane or flammable hydrocarbons).



LOCATE THE SERVICE FITTINGS

Next, you need to locate the service fittings on the A/C system. There are two: a LOW side fitting and a HIGH side fitting. The LOW side fitting is usually located on the suction hose or line that goes from the accumulator to the compressor. The HIGH side fitting is located on the line that goes from the compressor to the condenser.

On older R12 systems, the LOW and HIGH pressure service fittings are screw-type schrader valves. On newer R134a systems, the LOW and HIGH side service fittings are quick-connect style fittings. The LOW pressure fitting is SMALLER than the HIGH pressure fitting.



AIR CONDITIONING RECHARGE PROCEDURE

1. Connect the recharge service hose and valve to a can of refrigerant.

2. Turn the valve on the service hose to puncture the top of the can.

3. SLOWLY turn the valve back out to release a small amount of refrigerant into the hose. This will blow air out of the hose (which you do not want in your A/C system).

4. Close the valve so no more refrigerant escapes, then quickly connect the other end of the service hose to the LOW pressure service fitting on the A/C system.

CAUTION: DO NOT connect a can of refrigerant to the HIGH side service fitting. The operating pressure inside the A/C system when it is running may exceed the burst strength of the can, causing the can to explode! This should be impossible to do because the service hose for recharging the A/C system will only fit the smaller LOW pressure service fitting. Even so, you should be aware of the danger.

5. Hold the can UPRIGHT so no refrigerant liquid enters the service hose. You only want VAPOR to be pulled into the A/C system (the compressor may be damaged if it sucks in a big dose of liquid!).

6. OPTIONAL BUT HIGHLY RECOMMENDED: You should use a gauge to monitor the recharging process. Though not absolutely necessary, a gauge will help you recharge your A/C system more accurately, and reduce the chance of undercharging or overcharging (either of which will reduce cooling performance).

A high pressure A/C gauge can be connected to the HIGH pressure service fitting, or a low pressure A/C gauge to the LOW pressure service fitting, or gauges can be attached to both fittings (that is what professional technicians do).

NOTE: Some DIY recharging kits include a low pressure gauge on the service hose or on a trigger-grip style can dispenser.






7. Start the engine and turn the A/C on MAX/HIGH.

8. NOTE: The compressor may not engage if the system is too low on refrigerant. The low pressure cutout switch will prevent the compressor from running if the system is too low on refrigerant (this is done to protect the compressor from damage due to a lack of proper lubrication). The compressor must be running to suck refrigerant through the service hose into the system. So if it is not engaging when you turn the A/C on, you may have to supply battery voltage directly to the compressor clutch using a fused jumper wire. Look for a single wire connector near the front of the compressor, unplug it and hook up a jumper wire to the battery POSITIVE terminal. This should cause the clutch to engage and the compressor to run.



9. OPEN the valve on the service hose so refrigerant vapor will flow from the can into the A/C system. It may take up to 10 minutes or more per can to suck all of the refrigerant out of the can into the A/C system. Feel the air coming out of the ducts inside the vehicle. It should be getting colder.

10. If you are using a high or low pressure gauge (or both) to monitor recharging, look at the gauge(s).



LOW pressure gauge: When the reading is between 25 and 40 psi with the A/C running, STOP. The system is fully charged and should be cooling normally. DO NOT add any more refrigerant. If the gauge is over 50 psi, you have overcharged the system with too much refrigerant.


High pressure gauge: When the reading gets up around 200 to 225 psi (R12), or225 to 250 psi (R134a), STOP. The system is fully charged and should be cooling normally. DO NOT add any more refrigerant.

NOTE: The high and low pressure readings will vary depending on the system and ambient temperatures (higher temperatures cause higher system pressure readings).

Refer to the vehicle manufacturer specifications for normal system operating pressures, and the total refrigerant capacity of the system. Most newer passenger car A/C systems do not hold much refrigerant (only 14 to 28 oz.), so you don't want to add too much if the system is low. One can of R134a typically holds 12 oz. of refrigerant.

11. If the system needs more refrigerant after adding one can, you can add a second can. CLOSE the valve on the service hose, then disconnect the hose from the empty can, screw a new can onto the service hose valve, turn the valve to puncture the new can, then turn the valve all the way back out again so refrigerant can flow through the hose into the A/C system.

When you have finished, turn the engine off. CLOSE the valve on the can of refrigerant before disconnecting the service hose from the LOW pressure fitting (in case there is any refrigerant left in the can). Don't vent any left over refrigerant from the can. Leave the service hose attached to the can with the valve closed so you can save the refrigerant for a future recharge.

Remember to replace the plastic caps over the service fittings, and remove the jumper wire from the compressor if you had to jump it to make it run.
IF THE A/C SYSTEM STOPS BLOWING COLD AIR AFTER A FEW DAYS, WEEKS OR MONTHS

If your A/C stops blowing cold air several days, weeks or months after you recharged it, it means the system has a leak and the refrigerant is escaping. You should add some leak detection dye to the system to find the leak. The leak should then be repaired before the system is recharged again, otherwise you are just wasting your time recharging the system over and over again.






Here a gauge set and vacuum pump as used in the video, the gauge sets and vacuum pumps are what we use.

Last edited by Holly Goodhead; 19-04-2017 at 07:18 PM.
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Old 17-04-2017, 07:26 PM
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Troubleshoot Air Conditioning

A/C COOLING PROBLEM?

The most likely cause of an automotive air conditioner cooling problem is no refrigerant in the system. If the refrigerant has escaped past a leaky compressor or O-ring seal, leaked out of a pinhole in the evaporator or condenser, or seeped out through a leaky hose, the leak needs to be identified and repaired before the system is recharged.

On many systems, the compressor will not turn on if the refrigerant is low because the "low pressure safety switch" prevents the compressor clutch from engaging if system pressure is low. This protects the compressor from possible damage caused by a lack of lubrication.


One of the first things you should check, therefore, is compressor engagement. If the compressors magnetic clutch is not engaging when the A/C is turned on, the problem may be a blown fuse or a wiring problem. If the fuse is blown, replacing it may restore cooling temporarily. But the underlying reason for the fuse blowing in the first place needs to be identified and corrected to prevent the same thing from happening again.

If the magnetic clutch is receiving voltage but is not engaging the compressor, the clutch is defective and needs to be replaced. If there is any evidence of leakage around the compressor shaft seal, the seal should also be replaced.

If the clutch works but fails to turn the compressor (the belt may squeal in protest!), the compressor has seized and needs to be replaced.

Compressor failures are usually the result of loss of lubrication, which in turn may be due to low refrigerant in the system, a blockage (such as a plugged orifice tube which prevents refrigerant and oil from circulating to the compressor), loss of lubricant due to leaks or improper service procedures (not adding oil to the system to compensate for oil lost through leakage or component replacement), or use of the wrong type of lubricant.

R-12 systems require mineral oil while R-134a systems require various types of PAG oil or POE oil. Using mineral oil in a newer R-134a system can cause serious lubrication problems as can using the wrong grade (viscosity) of PAG oil. Always follow the vehicle or lubricant manufacturers compressor oil recommendations.

The next thing you should check when troubleshooting a no cooling problem is system pressure. For this, you need a set of A/C service gauges. Attach your service gauges to the high and low service fittings. If both the high and low side pressure gauges read low, the system is low and needs recharging. But before any refrigerant is added, check for leaks to find out where the refrigerant is going.


AIR CONDITIONING PROBLEM: REFRIGERANT LEAKS

All vehicles leak some refrigerant past seals and through microscopic pores in hoses. The older the vehicle, the higher the rate of seepage. Newer vehicles have better seals and barrier style hoses so typically leak less than a few tenths of an ounce of refrigerant a year. But system capacities also tend to be smaller on newer vehicles, so any loss of refrigerant will have more of an adverse effect on cooling performance.

Various methods can be used to check for leaks. The telltale oil stains and wet spots that indicate leaks on older R-12 systems are less apparent on the newer R-134a systems because PAG lubricants are not as "oily" as mineral oil. This makes it harder to see leaks.

Leaks can be found by adding special dye to the system (available in pressurized cans premixed with refrigerant), an electronic leak detector, or plain old soapy water (spray on hose connections and watch for bubbles -- requires adding some refrigerant to system first and turning the A/C on). Once you've found a leak, repairs should be made prior to fully recharging the system. Most leak repairs involve replacing O-rings, seals or hoses. But if the evaporator or condenser are leaking, repairs can be expensive.






POOR COOLING PERFORMANCE

Diagnosing an A/C cooling problem is best done by connecting a gauge set to the high and low pressure service fitting on the system. Though poor cooling is often due to a low charge of refrigerant, it can also be caused by many other factors (see chart above).

How to tell if your A/C system needs refrigerant: look at the LOW pressure gauge reading when the engine is OFF. On an 80 degree day, the LOW gauge should read about 56 psi or higher if the A/C system contains an adequate charge of refrigerant. On a 90 degree day, the LOW side reading should be about 70 psi or higher. If the LOW gauge reading is less than this, the A/C system probably needs some additional refrigerant.

Refer to the vehicle manufacturer specifications for normal system operating pressures, and the total refrigerant capacity of the system. Most newer passenger car A/C systems do not hold much refrigerant (14 to 28 oz.), so you don't want to add too much if the system is low.


AIR CONDITIONER PROBLEM: INTERMITTENT COOLING

An A/C system that blows cold air for awhile then warm air is probably freezing up. This can be caused by air and moisture in the system that allows ice to form and block the orifice tube.

Evacuating the system with a vacuum pump will purge it of unwanted air and moisture. Evacuation should be done with a vacuum pump that is capable of achieving and holding a high vacuum (29 inches) for at least 30 to 45 minutes.



Vacuum pump and gauge set.

For best performance, an A/C system should contain less than 2% air by weight. For every 1% increase in the amount of air that displaces refrigerant in the system, there will be a corresponding drop of about one degree in cooling performance. More than 6% air can cause a very noticeable drop in cooling performance, and possibly cause evaporator freeze-up.

Air can get inside a system through leaks, by not evacuating the system prior to recharging it, and/or by recharging the system with refrigerant that is contaminated with air. Recovery equipment can suck air into the recycling tank if an A/C system contains air or if the system has a leak. For this reason, the refrigerant recovery tank on recycling equipment must be checked and purged daily. On some equipment, this is done automatically. But on equipment that lacks an automatic purge cycle, tank pressure and temperature has to be measured and compared to a static pressure reference chart.

Some refrigerant identifier equipment can detect air in the system as well as other contaminants. An identifier should be used to check the refrigerant before the system is serviced to prevent cross-contamination of recovery and recycling equipment.



Possible causes of intermittent cooling in a manual A/C system that might be caused by an electrical problem include:

Faulty low pressure cutout switch. This switch prevents the compressor from running if the refrigerant level is low. If the cutout switch is not reading correctly, it can prevent the compressor from coming on.

Faulty compressor clutch. The magnetic clutch on the compressor requires full battery voltage to engage. If the voltage to the clutch is low, or the clutch coils have too much resistance, or the air gap in the clutch is too great, the clutch may not engage to drive the compressor.

Faulty compressor clutch relay. Check to see if the relay is receiving voltage when the A/C is turned on. Also check the relay wiring and ground connections. If bypassing the relay with a jumper wire or routing battery voltage directly to the compressor clutch makes the A/C work, the relay is probably bad.

Faulty A/C control switch. The switch may be worn and not making good contact when it is turned on.

Some possible causes of intermittent cooling (or no cooling) on automatic A/C systems include all of the above, plus:

A problem in the control module or control head (this usually requires using a dealer scan tool to read fault codes and perform self-diagnostics).

A bad temperature sensor (an ambient air temperature sensor, interior air temperature sensor, evaporator temperature sensor, or sunload sensor). Again, a factory scan tool is usually required to perform diagnostics on the system.

Last edited by Holly Goodhead; 19-04-2017 at 12:01 PM.
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Old 17-04-2017, 07:45 PM
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AIR CONDITIONING PROBLEM: NOISE

Noise from the compressor usually means the compressor is on its way out. But noise can also be caused by cross-contaminated refrigerant (operating pressure too high), air in the system or the wrong type of compressor lubricant.

Noise can also be caused by hoses or other parts rattling against other components in the engine compartment. Check the routing of the hoses, support brackets, etc., to pinpoint the noise.


TROUBLESHOOTING AIR CONDITIONING ODOR

If a vehicles air conditioner blows out air that smells like the inside of old gym sneaker when the A/C is turned on, microbes are growing on the evaporator. Mold likes damp, dark places. Bacteria can also thrive under such conditions. Besides smelling bad, it can be unhealthy to breathe (ever hear of Legionnaires Disease?).

To get rid of the unwanted organisms, various chemicals can be sprayed on the evaporator directly or through the blower ducts or air intake. Many replacement evaporators have a special chemical coating that inhibits the growth of mold and bacteria. The drainage tubes that carry condensation away from the evaporator should also be inspected and cleaned.


A/C FLUSHING

If the compressor has failed, or the system is full of sludge or contamination, the condenser, evaporator and hoses should all be flushed with an approved flushing chemical (such as Dura 141b) to clean the A/C system. Flushing can help prevent repeat compressor failures and system blockages by dislodging and cleaning out sludge and debris. Replacing badly contaminated parts such as the condenser, accumulator or receiver-drier and orifice tube or expansion valve is another way to get rid of these contaminants, but flushing is usually a more practical and economical choice. Regardless of which approach you use, the orifice tube or expansion valve should always be replaced when contamination is found.

NOTE: Some types of compressors can be very difficult to flush completely. These include "parallel" flow condensers and those with extremely small passageways. If contaminated, these types of condensers must be replaced to reduce the risk of a repeat compressor failure. Installing an in-line filter is also recommended for added insurance,

When a compressor fails, a lot of metallic debris is often thrown into the system. Most of this debris collects in the condenser where it can cause blockages that reduce cooling performance. If the debris is carried through the condenser and enters the liquid line, it can plug the orifice tube or expansion valve. This can block the flow of refrigerant and lubricating oil causing a loss of cooling and possible compressor damage. Debris can also migrate backwards from the compressor through the suction hose causing blockages in the accumulator or receiver-drier.

Another source of trouble can be debris from old hoses that are deteriorating internally. Tiny flakes of rubber can be carried along to the orifice tube or expansion valve and cause a blockage.

Sludge is usually the result of moisture-contamination. The blackish goo that results can damage the compressor and plug the orifice tube or expansion valve. The moisture-absorbing "desiccant" in the accumulator or receiver-drier is supposed to prevent this from happening. But the desiccant can only hold so much moisture. Once saturated, sludge begins to form. So you should also replace the accumulator or receiver-drier if the system is contaminated, has leaks or must be opened up for repairs.

Another reason for flushing is to remove residual lubricating oil from the system. This should be done when retrofitting an R-12 system to R-134a. It should also be done if the lubricating oil is contaminated or the system contains the wrong type of oil for the application. Flushing out the old oil can prevent oil overcharging, reduced cooling performance and/or lubrication incompatibility problems.

For added insurance after flushing, you can install a high side filter to protect the orifice tube or expansion valve from any residual debris that might still be in the system, and/or a second filter in the suction hose to protect the compressor.


R134A RETROFIT

As long as R-12 is available, there is no real reason to convert older vehicles to R-134a. That is because R-12 systems cool best when charged with R-12 refrigerant. But converting to R-134a does make sense if your A/C system requires major A/C repairs (such as a new compressor, condenser or evaporator). The extra cost involved to make the changeover to R-134a does not add that much to the total repair bill.

A basic retrofit procedure can be done one of two ways. The "Type 1" retrofit follows the OEM recommended procedure and generally involves removing all the old mineral oil from the system, replacing the accumulator or receiver-drier with one that contains a desiccant (X-7) which is compatible with R-134a, replacing O-rings (if required), installing or replacing a high pressure cutout switch and/or orifice tube (if required), then adding the specified PAG oil and recharging the system with R-134a.The law also requires the installation of R-134a fittings on the high and low service ports to reduce the chance of refrigerant cross-contamination the next time the vehicle is serviced, and labels that identify the system has been converted to R-134a.


"Type 2" procedure is more of a "quick and cheap" approach to retrofit. On many 1989 through 1993 vintage vehicles, the R-12 A/C systems can be converted to R-134a by simply recovering any of the R-12 that is left in the system (NOTE: it is illegal to vent refrigerant into the atmosphere!), adding POE oil (which is compatible with both types of refrigerant), and then recharging with R-134a.

NOTE: Type 2 conversions cannot always be done on some vehicles because their compressors may not be compatible with R-134a (any compressor with Viton seals has to be replaced). This includes original equipment compressors such as Tecumseh HR980, some Keihin compressors and some Panasonic rotary valve style compressors in older Nissan vehicles.

Durability is another concern. Because R-134a raises compressor discharge pressures and increases the compressors work load, some lightweight compressors may not be rugged enough to tolerate R-134a over the long haul. This applies to the Harrison DA6 and Ford FX-15 compressors. The Harrison DA6 can be replaced with a HD-6, HR-6 or HR-6HE compressor. The Ford FX-15 compressor can be replaced with a FS-10 compressor.

Last edited by Holly Goodhead; 17-04-2017 at 07:53 PM.
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Old 17-04-2017, 07:57 PM
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Air Conditioning Service Equipment

If you want to service the air conditioning system on your vehicle, here are some A/C service tools you may need:

Gauge sets (2) One for older R12 A/C systems and one for newer R134a A/C systems. Two separate gauge sets are necessary because the hose connections are different, and you also want to avoid cross-contamination of refrigerants.
A gauge set is used to read the high and low side pressures in an A/C system. These readings can provide essential diagnostic information for troubleshooting cooling problems. The gauge set is also used when recharging the system with refrigerant.

Minimum requirements: The low pressure gauge should be capable of reading from zero to 30 inches of vacuum Hg, and zero to 250 psi. The high pressure gauge should have a range of zero to 500 psi.


Refrigerant recovery equipment. This is only required for professional repair shops, not do-it-yourselfers. Even so, it is illegal to vent ANY type of refrigerant into the atmosphere no matter who does it. clean air regulations require the recovery and recycling of the refrigerant from a vehicle's A/C system prior to performing any type of service work that involves opening up the system.

Refrigerant recovery and recycling equipment must meet Society of Automotive Engineers (SAE) standards. In addition, different types of refrigerant must not be intermixed. This requires a separate recovery/recycling machine for each type of refrigerant used: one for R12, one for R134a (or a combination machine that includes separate circuits and storage tanks for R12 and R134a), one for R-1234yf, and one additional recovery machine for any other "alternative" refrigerants that may be used (this includes blended refrigerants as well as RVs & trailers using R-22).

What's more, professional technicians who do A/C work must be "certified" as having successfully passed an EPA-approved training course on recycling and recovery procedures. This is NOT a requirement if you do your own repairs.

Thermometer for measuring air temperature at the A/C outlets to diagnose cooling performance. A thermometer should be capable of measuring air temperature from 20 degrees up to 100 degrees Fahrenheit. A non-contact infrared thermometer is also a useful tool for measuring the surface temperature of A/C hoses, the condenser and radiator.


Leak detector or leak detection dye to find refrigerant leaks. It is pointless to recharge an A/C system if it has a leak. It may work for awhile, but sooner or later the refrigerant will leak out again. The least expensive and easiest way to find leaks in your A/C system is to add dye to the system. After several days it will leak out and leave telltale stains where the system is leaking. Many dyes are fluorescent and will glow bright green or yellow when illuminated with an UV light. Electronic leaks detectors typically cost several hundred pounds and are too expensive for most DIY. But electronic leak detectors are good for finding leaks in hidden areas that are difficult or impossible to see directly (such as an evaporator leak inside the HVAC unit). Sensitivity depends on the model, but most can detect leaks as small as 0.1 to 0.4 ounces per year.

Vacuum pump for purging air and moisture from the A/C system prior to recharging it with refrigerant. The pump should be capable of pulling a minimum of 29.5 inches of vacuum Hg. (This is included in almost all recovery and recharging stations.) The A/C system also has to be purged if you open any hoses to replace any parts. Air and moisture get inside. Air displaced refrigerant and can reduce cooling efficiency, while moisture can form acids and sludge that can damage the compressor and other metal parts.

Refrigerant identifier is an expensive tool that many repair shops use to identify and verify the type of refrigerant in a vehicle's A/C system before they service it. This reduces the risk of cross-contaminating their A/C recovery/recycling equipment. The more sophisticated equipment will even reveal the exact percentages of various refrigerants and contaminants in the system. But these are expensive tools, costing over £1000 or more. So if you suspect bad refrigerant, take your vehicle to a shop that has one of these machines and have them check your refrigerant for contamination.

CAUTION: Flammable refrigerants such as propane or butane (which are illegal to use in mobile A/C systems) are dangerous and pose a serious explosion hazard if there's a leak and something ignites the fumes. A garage may well refuse to service your vehicle if your A/C system contains a flammable gas.

Last edited by Holly Goodhead; 17-04-2017 at 08:11 PM.
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Old 19-04-2017, 07:13 PM
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Default Why is the Condensor Corroded?

Why is the Condensor Corroded?



Nissens offer some possible causes for a corroded condensor and how to avoid future issues.

The condenser is placed in the front of the car and is typically attached to other heat exchangers in the engine compartment. The condenser is crucial for correct A/C system operation as it ensures that the refrigerant changes from a gas to a liquid form. This is achieved through the condensation process, where the refrigerant heat is extracted and exchanged with the ambient air.

PROBLEM

As one of the A/C components closest to the external environment, the condenser experiences extensive wear and tear during its lifetime. Climates that experience rain, snow and humidity can be rough on the condenser; as roads are covered with salt during the colder months, the saltwater will spray the exposed condenser and increase the risk of corrosion. A corroded condenser will increase the workload on other system components, especially the compressor. Many compressor claim cases reveal that a condenser with restricted efficiency was the reason for the compressor to overheat and seize.

SOLUTION

Regular visual inspection of the condenser surface can save expensive repairs. Any signs of corrosion or leaks on the condenser surface must be considered as threats for the system operation. Pay attention to the bottom part of the condenser, where tubes and fins are mostly exposed to extensive humidity and aggressive salt spraying. Oil residues on the condenser can indicate leaks and you should always replace a condenser that is leaking or has missing/deteriorated fins. When replacing condensers, choose parts with corrosion protection applied as this prolongs its lifespan considerably.

CONDENSER CORROSION – POSSIBLE ISSUES

Deterioration of condenser fins
Even if the condenser doesn’t leak and seems to be tight, the heat exchange capacity may have been reduced significantly. As corrosion attaches to the thin aluminum fins, the working surface area is reduced, decreasing the overall heat exchange capacity of the condenser.

Lack of fins
As the fins corrode over time, they will fall out of the condenser. With the number of fins reduced, the condensation process then becomes significantly more ineffective, creating an increased overload on the compressor. Removal of only one fin row from the condenser can reduce its thermal performance by up to 3%!

Leaking condenser
Testing has shown that a condenser with missing fins, due to corrosion caused by saltwater, will eventually start to leak. The leakage is caused as the lack of fins destabilises the condenser construction, making it more vulnerable to wear and tear. As the refrigerant disappears, the system won’t function properly. Furthermore, as the lubricant can’t be distributed in an empty running system, the compressor will be exposed to overheating and seizure.

Last edited by Holly Goodhead; 19-04-2017 at 07:41 PM.
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Old 19-04-2017, 07:32 PM
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Default Is The Condenser Clogged?

Is The Condenser Clogged?

The condenser is a crucial component for ensuring correct A/C system operation. Placed inthe front of the car, and typically attached to other heat exchangers in the engine compartment, it ensures that the refrigerant changes from a gas to a liquid form. This is achieved through the condensation process,
where the refrigerant heat is extracted and exchanged with the ambient air.


PROBLEM

When impurities develop in the system, the thin channels of the condenser will quickly clog. This can
restrict the refrigerant flow, eventually reducing the unit’s ability to exchange heat. In most cases this will eventually cause overpressure in the system, which is extremely harmful for the compressor.

Condensers with micro tube technology tend to be the ones at the greatest risk. While micro tube technology offers an outstanding cooling performance, the thin fins are more exposed to stoppages. As the flow is compressed to a more confined area, fewer impurities are needed for clogging to occur.


SOLUTION

To keep the condenser in good condition, the receiver dryer must always be replaced during a compressor replacement, if the circuit has been exposed to ambient air, or the system has run empty, due to leakages. If none of these events occur, it’s recommended to replace the receiver dryer every second year.

Furthermore, you should always perform a system flush after a compressor breakdown.
Make sure that no flushing agent residues remain in the system after flushing. Always use the recommended oil and additives. Replace the condenser in cases of doubt.


Common cause for condenser inner clogging.

No/poor flushing
A thorough system flush must always be performed prior to a new component
installation – especially after a compressor seizure. When a compressor has seized, metal chips
can break off and cause clogging in the system. Furthermore, carbonised oil particles, developed
due to the compressor overheating, can cause clogging in the system and must be flushed.


Wrong use of additives

Incorrect additives, or improper application of additives, can cause system contamination.
This is often caused by crystalised leak-stop agents and/or Teflon that has peeled off inner parts
of the compressor. Teflon peeling off can be caused by aggressive, and not properly removed,
cleaning agents.


Incorrect lubricant

A lubricant with a too high viscosity can easily clog the condenser – especially
condensers built in micro tube technology, due to the confined flow in the fins.


Receiver dryer in poor condition

Poor condition of the receiver dryer means that it will become less efficient in filtering
particles, increasing the risk of impurities flowing through the system. This will eventually lead
to clogging of the condenser and other components.




Black, carbonised oil will quickly clog the condenser’s inner tubes.



Visible soiling at the condenser inlet.



Oil drained from a seized compressor. The visible contaminations are spread in the entire system, including the condenser.



Worn out receiver dryer (or desiccant bagcartridge) often results in clogging of the condenser’s inner tube.

Last edited by Holly Goodhead; 19-04-2017 at 08:05 PM.
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Old 19-04-2017, 07:55 PM
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Angry A/C – A Strategy For Success

A/C – A Strategy For Success



Today, virtually every vehicle presented for routine mechanical servicing or accident repair has been factory-fitted with an air conditioning (A/C) system. In fact, A/C is now such standard equipment that motor factors and technicians alike are passing up significant profit opportunities if they haven’t developed a strategy to maximise associated parts sales when various A/C components have to be
replaced.

Added value sales accrue when service technicians take a ‘best practise’ approach to the A/C system as a whole, not just the principal component that is being changed. For example, it’s a matter of routine for workshops to fit a new tensioner and, perhaps, a new water pump when replacing a timing belt.

However, workshops can reap similar rewards from additional parts sales if they adopt the
same approach when changing A/C components. Just as importantly, from the perspective of satisfying and retaining the customer, you can point to the fully restored efficiency, integrity and reliability of the system as justification for the expense.


How does the A/C system work?

The A/C system is formed by a closed circuit of pipes connecting the various components, with a central compressor circulating the refrigerant through the system. The compressor significantly increases the
temperature of the gaseous refrigerant before it passes to a condenser, through which it is forced under high pressure, causing it to shed heat and condense from gas to liquid.

From the condenser, the refrigerant – still under high pressure – then travels to a receiver drier, which filters out moisture and other contaminants before progressing to a thermo expansion valve or fixed orifice tube which is located just ahead of an evaporator. The pressure of the refrigerant drops as it enters the evaporator, with cooling taking place as the process of evaporation changes i2ts state back to gas from liquid.


Like the condenser, the evaporator is a large surface area heat ex changer, which distributes the cold from evaporation to the surrounding area before the ‘conditioned air’ is blown from the ventilation system into the interior of the vehicle. The refrigerant then returns to the compressor for the process to
start again. When a fixed orifice tube is insitu there is a suction accumulator placed on the low side of the circuit and the receiver drier isn’t part of the vehicle A/C system.


Additional sale





All through the process, every part in the system represents a potential additional sale. When replacing the compressor for ex ample, look at the receiver dryer and the thermo expansion valve as well and don’t overlook all the associated ‘O’ rings, oil, dye and flushing fluid commodities. The same thoughts apply when replacing the condenser.

Every second year the receiver drier/suction accumulator should be replaced anyway and if you change any other component and open the A/C system to atmosphere in the interim, a new receiver drier/suction accumulator should certainly be fitted due to moisture going in to the system.

Stations ready



Naturally, in order to undertake service and repair work on an A/C system, technicians need to use a high quality A/C service station, which is where our sister company HELLA GUTMANN SOLUTIONS steps in. Its comprehensive ‘Husky ’ range of mobile A/C service stations for both R134a and R1234yf
refrigerants prov ide3s the essential solution for all conventional, hybrid and electric vehicles.

The compact, entry level Husky 150 is designed for easy three step operation, but still incorporates several features commonly found on more costly units. Also for R134a refrigerant, the Husky 300 is a fully automatic station boasting leak detection, hermetically sealed oil/UV management and POE filling system functions, among other advanced features.

The range topping fully automatic Husky 3000 and Husky 3500 service stations incorporate the latest technology and industry leading features relevant to R1234yf refrigerant A/C systems, such as high
precision filling, leak detection and refrigerant analysis functions, plus an integrated print-out facility to communicate results directly with the customer.

Last edited by Holly Goodhead; 19-04-2017 at 08:29 PM.
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Old 19-04-2017, 08:18 PM
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Lightbulb Why do hybrids use high voltage A/C compressors?

Why do hybrids use high voltage A/C compressors?

Vehicles with full-hybrid technology use high voltage compressors that are not dependent on the running of the combustion engine. This makes for greater A/C comfort in such vehicles.

A vehicle’s interior that has become overheated can now be cooled down to the desired temperature before the start of any journey by using a remote control. This stationary cooling process can only be brought about if sufficient battery capacity is available.

The compressor is controlled with the lowest possible output with the necessary A/C requirements being taken into account. In the high voltage compressors used today, the power is regulated by adjusting the rotary speed in steps of 50 min-1. It is therefore not necessary to have an internal power control.

Function and design
In contrast to the ‘swash plate’ principle, which is primarily used in the belt-driven compressor field, high voltage compressors use the ‘scroll’ principle to compress the refrigerant. The benefits are that the weight is reduced by approximately 20% and there is a reduction in the cylinder capacity of the same amount, whilst the output remains identical.

In order to generate the right amount of torque for the drive of the electric compressor, a DC voltage of over 200V is used.


Specialist subject



You should be aware that appropriate staff training is required for the servicing of hybrid vehicles, with further skills imperative for those who service and repair the complex thermal management systems found in hybrids. In Germany, for example, those employees who work on high voltage systems are obliged to attend an additional two-day course in order to qualify as an “Electrician for High Voltage Systems”.

The course teaches the technician to recognise the risks when working on systems of this kind and also how to switch off all the current to the system for the duration of the work. It is prohibited for people who have not attended specific training courses to work on high voltage systems.

Also, tasks dealing with general servicing and repairs (such as work on exhaust systems, shock absorbers, oil changes and the changing of tyres) may only be carried out by employees who have attended the same course, in order to learn about the risks associated with these types of systems.

Tools of the trade
It is also essential to use tools that comply with the specifications provided by the manufacturer of the hybrid vehicle. During the A/C check and service, steps must be taken to ensure that the electric A/C compressors ARE NOT lubricated with standard PAG oils, as these don’t have the necessary insulation properties. POE oil or a special type of PAG oil is normally used instead, as these have the required properties.

Consequently, A/C service units with an internal rinsing function and a separate fresh oil reservoir should be used for the A/C check and service in hybrid vehicles. This then ensures that any mixing of the various types of fresh oil is prevented.


Disclaimer

This help topic is subject to changes without notification. The information within is carefully checked and considered to be correct. This information is an example of our investigations and findings and is not a definitive procedure. The Sixties Garage accepts no responsibility for inaccuracies. Each vehicle may be different and require unique test settings.

Last edited by Holly Goodhead; 19-04-2017 at 08:56 PM.
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