HVAC 21 STEP INSPECTION ACTION or elsewhere Are refrigerant’s high-pressure and low-pressure values low? No Go to step 14 7 Verify whether malfunction is in expansion valve and receiver /drier or elsewhere immediately after A/C compressor operates, does refrigerant’s high-pressure value momentarily rise to correct value, then fall and stay below it? (Is there negative pressure on low-pressure side?) Yes Go to next step No Go to step 10. 8 Verify whether malfunction is in expansion valve or receiver/drier. Turn A/C switch off and air conditioner stop for 10 minutes start engine turn both A/C switch and fan switch on. Does malfunction occur after compressor turn on? Yes Go to next step No Replace condenser and vacuum refrigerant line more than 30 minutes by vacuum pump, and refrigerant to specified level. (Since water has intermixed in receiver/drier and it is saturated, replacement is necessary.) 9 Verify that expansion valve heatsensing tube within cooling unit is positioned securely and correctly is expansion valve heat-sensing tube within cooling unit securely installed in proper position? Yes Replace expansion valve. (Since valve closes too much replacement is necessary.) No Install heat-sensing tube securely in proper position. 10 Inspect refrigerant lines inspect refrigerant lines Is piping free of damage and cracks? Are piping connections free of oil grime? (visual inspection) Are piping installation points on a/c compressor free of gas leakage? Are piping installation on cooling unit free of gas leakage? Perform gas leak inspection using gas leak tester. Are above items okay? Yes Go to next step No If piping or an A/C component is damaged or cracked, replace it. 11 Inspect evaporator piping connections in cooling unit for gas leakage are piping connections for evaporator in cooling unit free of gas leakage? Yes If the vane makes a noise, add 10ml of compressor oil to the A/C compressor. Verify that the noise is no longer heard. Adjust refrigerant to specified amounts. No If piping is damaged or cracked, replace it.
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