AIR CONDITIONING SYSTEM — Troubleshooting 3. INSUFFICIENT REFRIGERANT Condition: Insufficient cooling Symptom seen in refrigeration system | Probable cause | Diagnosis | Remedy Pressure low at both low and high pressure sides Bubbles seen in sight glass Insufficient cooling performance | Gas leakage at some place in refrigeration system | Insufficient refrigerant in system or Refrigerant leaking | Check with leak tester and repair or Charge refrigerant to proper amount 4. POOR CIRCULATION OF REFRIGERANT Condition: Insufficient cooling Symptom seen in refrigeration system | Probable cause | Diagnosis | Remedy Pressure low at both low and high pressure sides Frost on tubes from receiver to unit | Refrigerant flow obstructed by dirt in receiver | Receiver clogged | Replace receiver