DEFINITION: The low side pressure is lower than normal and the high side pressure is higher than normal.

Were you sent here from the A/C System Performance Test?

Go to Step 2

Go to Air Conditioning (A/C) System Performance Test

Caution: Refer to Moving Parts and Hot Surfaces Caution in the Preface section.

Feel the liquid line before the thermal expansion valve (TXV).

Is the liquid line cold before the TXV?

Go to Step 3

Go to Step 8

Feel along the surfaces of the following high side components:

Did you detect an abrupt drop in temperature along the surfaces of any of the listed components?

Go to Step 7

Go to Step 4

1. Feel the liquid line at the TXV for extreme cold, possibly accompanied by heavy frost.
2. Feel along the liquid line beyond the TXV for warm temperature.

Is the liquid line extremely cold at the TXV and warm beyond the TXV?

Go to Step 11

Go to Step 5

Feel along the surfaces of the following low side components:

Did you feel an abrupt temperature change along the surfaces of any of the listed components?

Go to Step 7

Go to Step 6

Feel along the surfaces of the low and the high side components.

Are the temperatures of these components only mildly warm?

Go to Step 14

Go to Step 8

1. Recover the refrigerant. Refer to Refrigerant Recovery and Recharging .
2. Remove the restriction from the component, or replace the component which produced an abrupt temperature drop.

Is the repair complete?

Go to Step 17

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1. Recover the refrigerant and evacuate the system. Refer to Refrigerant Recovery and Recharging .
2. Record the weight of the recovered refrigerant.
3. Compare the weight of the recovered refrigerant with the system capacity. Refer to Refrigerant System Capacities .

Is the weight of the recovered refrigerant charge greater than 75 percent of the total system capacity?

Go to Step 9

Go to Step 10

Recharge the A/C system. Refer to Refrigerant Recovery and Recharging .

Is the operation complete?

Go to Step 12

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1. Leak test the system. Refer to Leak Testing .
2. Repair any leaks.

Is the repair complete?

Go to Step 17

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The TXV is restricted.

Replace the TXV. Refer to Thermal Expansion Valve Replacement .

Are metal flakes present?

Go to Step 12

Go to Step 13

1. Remove the refrigerant filter. Refer to Air Conditioning (AC) Refrigerant Filter Replacement .
2. Inspect the refrigerant filter for debris.

Was there debris present?

Go to Step 16

Go to Step 17

If the refrigerant filter was restricted with a brown or black residue, perform the following procedure:

1. Flush the A/C system. Refer to Flushing .
2. Replace the condenser. Refer to Condenser Replacement .

Are the repairs complete?

Go to Step 17

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1. Recover the refrigerant. Refer to Refrigerant Recovery and Recharging .
2. Remove the compressor hose assembly from the compressor. Refer to Compressor Hose Assembly Replacement .
3. Inspect for the presence of debris in the compressor suction port.

Is debris present in the compressor suction port?

Go to Step 15

Go to Step 17

1. Remove the debris from the suction port.
2. Inspect the TXV for damage or debris. Refer to Thermal Expansion Valve Replacement .

Did you find evidence of damage or debris?

Go to Step 17

Go to Step 16

If a large amount of debris was collected from the refrigerant filter, perform the following procedure:

1. Replace the compressor. Refer to Air Conditioning Compressor Replacement .
2. Replace the refrigerant filter. Refer to Air Conditioning (AC) Refrigerant Filter Replacement .

Is the repair complete?

Go to Step 17

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Operate the system in order to verify the repair.

Did you find and correct the condition?

System OK

Go to Symptoms - HVAC Systems - Automatic