| Table 1: | Discharge High Pressure Abnormally High |
| Table 2: | Discharge Pressure Abnormally Low |
| Table 3: | Suction Low Pressure Abnormally Low |
| Table 4: | Suction Pressure Abnormally High |
| Table 5: | Suction and Discharge Pressure Abnormally High |
| Table 6: | Suction and Discharge Pressure Abnormally Low |
| Table 7: | Refrigerant Leaks |
Symptoms | Checks | Actions | |||
|---|---|---|---|---|---|
After stopping the compressor, the pressure drops quickly, then fails gradually. | There is air in the system. | Recover, evacuate, and recharge the system with the specified amount of refrigerant. | |||
The condenser is excessively hot. | There is excessive refrigerant in the system. | Recover, evacuate, and recharge the system with the specified amount of refrigerant. | |||
Reduced or no air flow through the condenser | The condenser or the radiator fins are clogged. | Clean the condenser or the radiator fins. | |||
The condenser or the radiator fan is not working properly. |
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The line to the condenser is excessively hot. | Restricted flow of refrigerant in the system | Locate and repair the restriction. |
Symptoms | Checks | Actions | ||||
|---|---|---|---|---|---|---|
The condenser is not hot. | Insufficient refrigerant in the system |
| ||||
High and low pressures are balanced soon after stopping the compressor. Low side pressure is higher than normal. | Faulty compressor | Repair or replace the compressor. | ||||
The outlet of the expansion valve is not frosted, low pressure gage indicates vacuum. | Faulty expansion valve | Replace the expansion valve. | ||||
Moisture in the system | Recover, evacuate, and recharge the system. |
Symptoms | Checks | Actions |
|---|---|---|
The condenser is not hot. | Insufficient refrigerant in the system | Repair the leaks. Recover, evacuate, and recharge the system. |
The expansion valve is not frosted and the low pressure line is not cold. Low pressure gage indicates a vacuum. | Frozen/Faulty expansion valve | Replace the expansion valve. |
Discharge temperature is low and the air flow from the vents is restricted. | The evaporator is frozen. | Clear the restricted evaporator case drain. |
The expansion valve is frosted. | The expansion valve is clogged. | Clean or replace the expansion valve. |
The receiver/dryer outlet is cool and the inlet is warm. | The receiver/dryer is clogged. | Replace the receiver/dryer. |
Symptoms | Checks | Actions |
|---|---|---|
Low pressure hose and check joint are cooler than the temperature around the evaporator. | The expansion valve is opened for too long. | Replace the expansion valve. |
Suction pressure is lowered when the condenser is cooled by water. | There is excessive refrigerant in the system. | Recover, evacuate, and recharge the system. |
Symptoms | Checks | Actions | |||
|---|---|---|---|---|---|
Reduced airflow through the condenser | The condenser or the radiator fins are clogged. | Clean the condenser and the radiator. | |||
The radiator cooling fans are not working properly. |
| ||||
The condenser is excessively hot. | There is excessive refrigerant in the system. | Recover, evacuate, and recharge the system. |
Symptoms | Checks | Actions |
|---|---|---|
Low pressure hose and metal end areas are cooler than the evaporator. | Clogged or kinked low pressure hose | Repair or replace the low pressure hose. |
Temperature around the expansion valve is low compared to that around the receiver/drier. | The high pressure line is clogged. | Repair or replace the high pressure line. |
Symptoms | Checks | Actions | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
The compressor clutch is dirty. | The compressor shaft seal is leaking. | Repair or replace the compressor. | ||||||||||||
The compressor bolts are dirty. | Leaking around a compressor housing bolt | Tighten the bolts or replace the compressor. | ||||||||||||
The compressor gasket is wet with oil. |
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