Plain-language explanation: This page is educational and does not replace testing the actual equipment.
Where restrictions occur
Common locations include filter-driers, TXVs, capillary tubes, distributors, kinked lines, and contaminated components.
Possible symptoms
Symptoms can include low suction pressure, high superheat, reduced capacity, temperature drop across the restriction, and partial frosting.
Why it can look like low charge
Both restrictions and low charge can starve the evaporator. Subcooling, temperature patterns, pressure response, and leak evidence help separate them.
What repair involves
Repair may require replacing the restricted component, correcting contamination, evacuating the system, and recharging it properly.
Frequently asked questions
Can moisture cause a restriction?
Yes. Moisture can freeze at a metering device or contribute to contamination and acid formation.
Can a kinked line restrict refrigerant?
Yes. A severely kinked or flattened line can reduce flow.
Can a restriction damage the compressor?
It can contribute to abnormal temperatures, poor lubrication return, and long run times.