Monday, October 17, 2011

How To Recharge Car's Air Conditioner

Its not very difficult.
Just know few Aspects to do this procedure.

Why and When to charge/Recharge Cars AC.
This is done when you loose refrigerant from the AC system.And when you loose refrigerant,the cooling problem will be noticed.To bring your AC cooling back to normal.The AC recharge has to be done.
For this you will need  few cans of refrigerant and a simple service hose connection.

The refrigerant is harmful to skin and eyes.So Avoid getting in contact with refrigerant and wear safety glasses,to take care of your eyes.


There are two types of refrigerants.On newer model cars,that is after 1995,the car uses R134A refrigerant.And old model cars that is before 1995,the car uses R12A refrigerant.Still before buying refrigerant get it confirmed with the Auto part store or local car mechanic.So you buy the right refrigerant.

Basically refrigerant is charged from low service port.
There are two service port on AC systems.
One is low service port and other is high service port.The Low service port is smaller then High service port.
The Low service port is located on the suction hose or line that goes from the accumulator to the compressor. The HIGH service port  is located on the line that goes from the compressor to the condenser.

On old model cars the service port fitting is screw-type schrader valve type.And on new model cars the service port fitting is quick-connect type.

Now the main procedure.That is Recharging the AC system.
I  previously mentioned on top,that you require service hose and refrigerant can.
So now connect the recharge service hose and valve to the CAN of refrigerant.
There is a valve on the service hose.Turn this valve on,turning the valve ON will puncture the top of refrigerant CAN.
Once the CAN is punctured,then slowly turn the valve in reverse,this will let the refrigerant to enter the hose.When you do this,the air in the system will start flowing out.The air should actually flow out, because if air is there in the system,then it will trap in between the refrigerant flow,and this causes cooling problems.So let the air to get out.
Once all the air is out, the refrigerant will start getting out and that you will see.Once you see refrigerant is getting out.Close the valve.Now the air is released and refrigerant is reached till the top.Then connect the other side of hose to the Low service port fitting.Please note, that hose has to be connected to Low service port fitting only.Do not connect to high pressure port,if you do so, the refrigerant can will burst or explode.--- The best part of the hose, is that it has fitting that only connects to Low side fitting,it will not fit properly to the high side.So connecting it wrong is rare.But still be careful.Hold the Refrigerant CAN in upright position.This is because  no refrigerant liquid enters the service hose. Only VAPOR has to be pulled into the A/C system because the compressor gets  damaged if it absorbs in a big dose of liquid in it.The refrigerant should not be overcharged,this damages compressor.The refrigerant should not be undercharged,this will not give required cooling.So to know, if AC system is charged accurately, there are gauges available at local Auto part store.Its call AC pressure gauge tool.

The gauges comes is many varieties.A high pressure gauge or a low pressure gauge tool.A high pressure A/C gauge can be connected to the HIGH pressure service fitting.If you get low pressure gauge tool then,low pressure A/C gauge to the LOW pressure service fitting.Also  gauges can be attached to both fittings .The AC repair/recharge technicians connect gauges to both ports.So it give details on both under charge and over charge.

There are  Some DIY recharging kits available in market,that includes a low pressure gauge on the service hose or on a trigger-grip style CAN dispenser.

So once you connect the gauge tool.Then start the engine.The engine should be ON,when AC system is getting charged.Then turn AC system to the MAX mode.

NOW read this point properly.This is main point.MANY users Stuck up at this point.
When you turn on your AC,the compressor should engage.When the compressor engages,then only the refrigerant will start entering the system.If the AC turned ON to MAX,but compressor is not getting engaged,then AC will not get charged.
WHY the compressor do not engage?
If the refrigerant is too low in the system, then compressor will not engage.This is a safety system, in car.Because if compressor engages with low refrigerant then compressor will get overheated and shorted.

BUT, now you are recharging the system with refrigerant,So now the refrigerant will enter the system.But if compressor will not engage then Refrigerant will not get charged.So in that case you have to manually engage the compressor.
There is a compressor clutch.That clutch is the part, that engages the compressor.You will have to jump the clutch directly to the battery.You will 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.

Once the valve is turned ON,the refrigerant will starter entering the AC system from refrigerant CAN. Basically per CAN will take up-to 8 minutes or 10 minutes to get complete empty.
If the system needs more refrigerant after adding one can, you can add a second can. To add another CAN of refrigerant CLOSE the valve on the service hose,Turn the valve off  then disconnect the hose from the empty CAN, screw a new CAN onto the service hose valve.As you did while attaching first CAN then  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.
Your AC system is Turned ON MAX,so you will notice that Air getting colder.Every AC system has refrigerant capacity.Confirm the exact capacity of refrigerant required for your car.This is mentioned in your cars owners manual.But if you don't have owners manual,then just consult it with the Auto part store.They have all the details.The older model cars take more refrigerant, because its refrigerant tank is bigger then newer model cars.
Most newer passenger car A/C systems do not hold much refrigerant (only 16 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 to 14 oz of refrigerant.

Now ,you will think one question,while reading this.How much refrigerant should i add.How will i know that refrigerant is full.
This is where the AC pressure gauge tool,comes in help.
On low pressure port, the tool will show reading between 25 to 40 psi with AC still running.When it shows in between this readings.Just stop.On high pressure reading,if it shows between  200 to 225 psi (R12), or 225 to 250 psi (R134a), STOP. The system is fully charged and should be cooling normally. DO NOT add any more refrigerant.

Now after  you finish recharging.First turn the engine OFF.Then close the valve,turn the valve off.Then disconnect the service hose from low port.Leave the service hose connected with Refrigerant CAN with the valve closed so you can save the refrigerant for a future recharge.Take care the drops or refrigerant don't fall on your hands or skin while remaining the service hose from low pressure fitting.There will be few drops left in the hose.Don't vent it on floor,just let it get into can.It will settle down in few minutes.
Close the valve to off position properly.Remove the jumper wire,which you connected to run the compressor.This is not always required,But in some cases jumper wire has to be connected to make the compressor run,.

If after few moths or weeks again.You notice LOW cooling then there a leak problem in AC system.The small amount of refrigerant is getting leaked. Basically refrigerant last for years.
So if there is a leak noticed.Then First the leak has to be repaired,before recharging refrigerant Again.Next time.

IF you want to know more about CAR AC and its problems:---


Fixing refrigerant leak?

Car AC Blows Warm Air ?

How to test AUTO AC pressure?

AUTO Air Conditioning Troubleshooting?


How to locate Car AC Refrigerant leak?


What causes INTERMITTENT COOLING on Car AC system?

Car AC making Noise?


For more car problems help.
This are best blog sites to refer:---

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