HVAC SYSTEM (HEATER, VENTILATOR AND A/C) > Refrigerant Pressure with Manifold Gauge Set

INSPECTION

Symptom

Probable cause

Repair order

High-pressure side is unusually high.

• Defective condenser fan motor

• Clogged condenser fin

• Too much refrigerant

• Air inside the system

• Defective receiver dryer

• Replace the fan motor.

• Clean the condenser fin.

• Discharge refrigerant.

• Replace the receiver dryer.

• After evacuating again, charge an appropriate amount of refrigerant.

High-pressure side is unusually low.

• Defective compressor

• Not enough refrigerant

• Clogged expansion valve

• Expansion valve frozen temporarily by moisture.

• Replace the compressor.

• Check for leaks.

• Replace the expansion valve.

• Fully evacuate the expansion valve.

Low-pressure side is unusually high.

• Defective compressor

• Defective expansion valve

• Too much refrigerant

• Replace the compressor.

• Replace the expansion valve.

• Discharge refrigerant.

Low-pressure side is unusually low.

• Not enough refrigerant

• Clogged expansion valve

• Expansion valve frozen temporarily by moisture.

• Saturated receiver dryer

• Check for leaks.

• Replace the expansion valve.

• Replace the receiver dryer.