Car-Air-Conditioner Servicing Guide!

Freon Charging

Car-air-conditioner servicing is a very interesting job. If you have the tools and equipments, you can save a lot of money if you do it yourself. But before you try anything else you should have the knowledge of refrigeration.

Now we know that the refrigeration cycle is as follows:

Refrigeration Cycle

The returning refrigerant from the evaporator circulates to the suction of the compressor.

It then compresses the low pressure low temperature refrigerant into high pressure and high temperature refrigerant.

When it reaches the condenser, the heat absorbed from the evaporator combine with the high pressure high temperature from the compressor, is released into the atmosphere.

Recycle Machine

The gas refrigerant condensate into liquid refrigerant, and is passing through a receiver/dryer, where the moisture content of the refrigerant is absorbed,

and the dirt, metal particles, are filtered after leaving the receiver/dryer.

The refrigerant then passes to the evaporator, where the heat inside the passenger compartment

Gauge manifold

is being absorbed. The liquid refrigerant turned to gas, and the cycle repeats again.

Knowing the refrigeration cycle, we begin our servicing by evacuating the system.

1) Hook up the gauge manifold, hang it on the hood catch. Connect the blue hose to the suction valve, and the red hose to the discharge valve. Close both blue and red hand valves.

Vacuum Pump

2) Connect the yellow hose to the inlet of vacuum pump.

3) Open both blue and red hand valves. Run the vacuum pump, after 10 to 15 minutes, the reading on the compound gauge should be 29 to 30 in. Hg vacuum.

But if the needle is steady on a lower reading, it means there is a leak in the system. If there is no leak, close both hand valves.

Freon Gas

4) Connect the yellow hose to a refrigerant tank, open tank valve. Open the blue hand valve slowly to allow refrigerant to enter the system.

5) When the pressure is around 30 psig, start looking for leaks by applying soap bubbles on fitting joints. If no leak is found, continue charging until your reading on the compound gauge is 60 psig.

6) Start the engine and run it at 600 rpm or until the compressor clutch is engaged.

7) The reading of the compound gauge will go down and the reading of the pressure gauge will go up to 200 psig.

8) Charge system until your reading on the compound gauge is 36 to 40 psig, and 200 to 210 psig on the pressure gauge.

9) Check the sight glass of the receiver/dryer, there should be no bubbles in it.

10) Disconnect gauge manifold and close hood.

As you can see, servicing a car air conditioner is very simple and straight forward.

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