TROUBLESHOOTING - Refrigerant pressure flowchart
G-35spec tableRefrigerant pressure flowchart
Refrigerant pressure flowchart
High- and low-pressure-side readings are higher than normal
Step-
ProcedureCheck condenser fins. (Refer to page G-54) Are they clogged or damaged?
Yes/NoYes
Cause and actionInsufficient condenser refrigeration / Clean or repair condenser fins (Refer to page G-64)
High- and low-pressure-side readings are higher than normal
Step-
ProcedureCheck condenser fins. (Refer to page G-54) Are they clogged or damaged?
Yes/NoNo
Cause and actionToo much refrigerant / Discharge refrigerant and recharge to proper amount (Refer to page G-50)
High- and low-pressure-side readings are lower than normal
Step1
ProcedureCheck all connections. Are there any oil stains?
Yes/NoYes
Cause and actionInsufficient refrigerant because of leakage / Repair leaks and recharge refrigerant to proper amount (Refer to page G-50)
High- and low-pressure-side readings are lower than normal
Step1
ProcedureCheck all connections. Are there any oil stains?
Yes/NoNo
Cause and actionGo to Step 2
High- and low-pressure-side readings are lower than normal
Step2
ProcedureCheck for leakage (Refer to page G-51) Are there any leaks?
Yes/NoYes
Cause and actionInsufficient refrigerant because of leakage / Repair leaks and recharge refrigerant to proper amount (Refer to page G-50)
High- and low-pressure-side readings are lower than normal
Step2
ProcedureCheck for leakage (Refer to page G-51) Are there any leaks?
Yes/NoNo
Cause and actionInsufficient charging / Recharge refrigerant to proper amount (Refer to page G-50)
High-pressure-side reading is a little lower than normal; low-pressure-side reading is a little higher than normal
Step-
ProcedureCheck heat-sensing tube. Is it in its proper position and securely connected to evaporator outlet pipe?
Yes/NoYes
Cause and actionExpansion valve opening too wide because of expansion valve malfunction / Replace expansion valve (Refer to page G-68)
High-pressure-side reading is a little lower than normal; low-pressure-side reading is a little higher than normal
Step-
ProcedureCheck heat-sensing tube. Is it in its proper position and securely connected to evaporator outlet pipe?
Yes/NoNo
Cause and actionExpansion valve opening too wide because heat-sensing tube is improperly installed / Reinstall heat-sensing tube properly (Refer to page G-68)
High-pressure-side reading rises to normal pressure range and then drops below range; low-pressure-side reading is negative
Step1
Procedure1. Turn A/C compressor off for about 10 minutes. 2. Turn A/C compressor on and immediately check pressure reading. Is pressure reading normal?
Yes/NoYes
Cause and actionExpansion valve clogged because of freezing by moisture / Discharge refrigerant and replace receiver/drier (Refer to page G-65)
High-pressure-side reading rises to normal pressure range and then drops below range; low-pressure-side reading is negative
Step1
Procedure1. Turn A/C compressor off for about 10 minutes. 2. Turn A/C compressor on and immediately check pressure reading. Is pressure reading normal?
Yes/NoNo
Cause and actionGo to Step 2
High-pressure-side reading rises to normal pressure range and then drops below range; low-pressure-side reading is negative
Step2
ProcedureCheck heat-sensing tube. Is it properly installed?
Yes/NoYes
Cause and actionExpansion valve clogged with foreign material / Expansion valve opening too wide because of expansion valve malfunction or heat-sensing tube leakage / Replace expansion valve (Refer to page G-68)
High-pressure-side reading rises to normal pressure range and then drops below range; low-pressure-side reading is negative
Step2
ProcedureCheck heat-sensing tube. Is it properly installed?
Yes/NoNo
Cause and actionExpansion valve opening too narrow because heat-sensing tube is improperly installed / Reinstall heat-sensing tube properly (Refer to page G-68)
No difference between high- and low-pressure-side readings
Step-
Procedure-
Yes/No-
Cause and actionImproper compression of A/C compressor / Repair or replace A/C compressor (Refer to page G-54)