Plain-language explanation: This page is educational and does not replace testing the actual equipment.
Why subcooling matters
Many TXV systems are charged using manufacturer-specified subcooling under appropriate operating conditions.
Low subcooling
Low subcooling may suggest low refrigerant charge, insufficient condenser liquid, or other operating conditions.
High subcooling
High subcooling may be associated with overcharge, restrictions, or refrigerant stacking in the condenser.
Why conditions matter
Outdoor temperature, airflow, coil cleanliness, line-set length, equipment design, and manufacturer instructions all affect interpretation.
Frequently asked questions
Is there one correct subcooling number?
No. The target is equipment-specific and often listed on the data plate or service literature.
Can a dirty condenser change subcooling?
Yes. Condenser airflow problems affect pressures, temperatures, and charging measurements.
Should refrigerant be added based on pressure alone?
No. Proper charging uses the correct manufacturer procedure and verified airflow.