Air Conditioning (A/C) Diagnostics - Pressure Zone B

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Step	Action	Yes	No
DEFINITION: The low side pressures is higher than normal and the high pressure is lower than normal. Malfunctioning A/C Compressor Refrigerant Under Charge
1	Were you sent here from the A/C System Performance Test?	Go to Step 2	Go to Air Conditioning (A/C) System Performance Test
2	After continued operation of the A/C system, do the low and high side pressures equalize or become static?	Go to Step 5	Go to Step 3
3	Refer to the pressures recorded during the A/C System Performance Test. Inspect for the following conditions: CAUTION: Refer to Moving Parts and Hot Surfaces Caution in Cautions and Notices. The low side pressure equal to or above the specified pressure range of the A/C Performance table. Refer to Air Conditioning (A/C) System Performance Test . The high side pressure is below the specified pressure range of the A/C Performance table. Refer to Air Conditioning (A/C) System Performance Test . The low side refrigerant line at the compressor feels cool-to-warm. The high side refrigerant line at the compressor feels warm-to-hot. Do the listed conditions exist?	Go to Step 5	Go to Step 4
4	Refer to the pressures recorded during the A/C System Performance Test. Inspect for the following conditions: CAUTION: Refer to Moving Parts and Hot Surfaces Caution in Cautions and Notices. The low side pressure is above the specified pressure range of the A/C Performance table. Refer to Air Conditioning (A/C) System Performance Test . The high side pressure is below the specified pressure range of the A/C Performance table. Refer to Air Conditioning (A/C) System Performance Test . The low side refrigerant line at the compressor feels warm. The high side refrigerant line at the compressor feels warm to hot. Do the listed conditions exist?	Go to Step 5	Go to Air Conditioning (A/C) System Performance Test
5	The A/C system has a low refrigerant charge. Evacuate and recharge the A/C system. Refer to Refrigerant Recovery and Recharging . Is the procedure complete?	Go to Step 6	-
6	Record the low and high side pressures as well as the I/P outlet air temperature after repairs are performed. Compare the pressures and outlet temperature to those listed in the A/C Performance Chart. Refer to Air Conditioning (A/C) System Performance Test . Are the readings within the specified ranges?	Go to Step 13	Go to Step 7
7	The A/C compressor is malfunctioning. Remove the expansion device and inspect for contamination. Refer to Expansion (Orifice) Tube Replacement (Front Only System) or Expansion (Orifice) Tube Replacement (Auxiliary System) . Are there metal flakes on the expansion device?	Go to Step 9	Go to Step 8
8	Inspect the expansion device for a brown, powdery residue indicating desiccant in the A/C system. Is there a brown, powdery residue present?	Go to Step 11	Go to Step 12
9	Remove the compressor hose from the compressor. Refer to Compressor Hose Assembly Replacement (LL8) or Compressor Hose Assembly Replacement (LM4) . Inspect for metal flake contamination at the line connections and the compressor ports. Is there metal flake contamination present?	Go to Step 10	Go to Step 12
10	Replace the A/C compressor. Refer to Compressor Replacement (LL8) or Compressor Replacement (LM4) . Replace the orifice tube. Refer to Expansion (Orifice) Tube Replacement (Front Only System) or Expansion (Orifice) Tube Replacement (Auxiliary System) . Evacuate and recharge the A/C system. Refer to Refrigerant Recovery and Recharging . Is the repair complete?	Go to Step 13	-
11	Flush the A/C system. Refer to Flushing (Front Only System) or Flushing (Auxiliary System) . Replace the orifice tube. Refer to Expansion (Orifice) Tube Replacement (Front Only System) or Expansion (Orifice) Tube Replacement (Auxiliary System) . Replace the A/C compressor. Refer to Compressor Replacement (LL8) or Compressor Replacement (LM4) . Replace the accumulator. Refer to Accumulator Replacement . Evacuate and recharge the A/C system. Refer to Refrigerant Recovery and Recharging . Is the repair complete?	Go to Step 13	-
12	Replace the A/C compressor. Refer to Compressor Replacement (LL8) or Compressor Replacement (LM4) . Evacuate and recharge the A/C system. Refer to Refrigerant Recovery and Recharging . Is the repair complete?	Go to Step 13	-
13	Operate the system in order to verify the repair Did you find and correct the condition?	System OK	Go to Symptoms - HVAC Systems - Manual in HVAC - Manual OR Go to Symptoms - HVAC Systems - Automatic in HVAC - Automatic