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DIAGNOSE – A/C SYSTEM DOESN’T BLOW COLD AIR

By Carl O’Reilly

SYMPTOM SUMMARY
The air conditioning system is not cooling as expected. The air conditioning system may require an extended period of operation to reach the desired output.

USUAL CAUSE
Low refrigerant level is the most likely cause of poor cooling from the air conditioning. If there is no cool air coming from the air conditioning system, an electrical malfunction could be the cause. A defective relay, compressor clutch coil or damaged compressor are all possibilities.

DIAGNOSIS
The air conditioning system is equipped with safety switches that automatically turn the compressor off when the A/C refrigerant level becomes low. This prevents compressor damage, since the lubricant for the compressor is circulated through the system by the refrigerant. When the pressure switches are activated, power to the compressor is interrupted regardless of the position of the A/C dash switch. Recent regulations have prevented most consumers from doing the repairs. Special equipment is now used to remove the refrigerant, referred to as “evacuate” prior to opening the refrigerant system. Special leak detectors are used to detect leaks around hoses, fittings, and valves. Once pinpointed, the leak will have to be repaired once the existing refrigerant, if any, is removed.

PRECAUTIONS, TIPS, and NOTES
The refrigerant system is under high pressure at all times. During operation, the high pressure side of the refrigerant system can reach pressures of over 275 PSI. Use extreme caution when working around the A/C system. Never disconnect or vent the refrigerant to the atmosphere. Refrigerant can cause extreme frost bite or blindness if it comes in contact with your skin or eyes. Repairs to the A/C system are best left to trained service personnel using the proper test and service equipment. Repairs can be made by the consumer, however, the system should be evacuated using the proper equipment by trained service personnel prior to any component replacement. After the system is repaired, it will have to be recharged using the same type of equipment.


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4 Responses to “Diagnose Ac System Doesnt Blow Cold Air”

  1. Brian says:

    I recently tried recharging my a/c system (5.3L chevy Silverado truck) with an “easy charge” system from my local auto parts store (attaches to the low side and press the trigger). I think I overcharged it because now the compressor clicks on for a couple seconds then off and only warm air is blowing. I bought a set of guages and an evac pump and evacuated the system, put in a new expansion valve, and tried it again, same result. The reading on the guages are LOW SIDE=high & HIGH SIDE=low. Did I f-up & need to replace the compressor/accumulator?

  2. Mr Sames says:

    Due to the expansion in the air compressor there are very advanced compressor are available in the market with the low risk factor and high power facility.

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