Lineset Charge Addition Calculator
Calculate refrigerant charge addition for extended linesets beyond factory pre-charge length. Enter refrigerant type, liquid line diameter, and lineset length to get the required additional charge in ounces and pounds.
R-410A Charge Reference
R-410A charge rates for common liquid line diameters.
- R-410A — 3/8" Line Charge — 0.6 oz/ft — small split systems and mini-splits
- R-410A — 1/2" Line Charge — 1.1 oz/ft — standard residential split systems
- R-410A — 5/8" Line Charge — 1.7 oz/ft — larger residential and light commercial
R-22 Charge Reference
R-22 charge rates for servicing existing systems.
- R-22 — 3/8" Line Charge — 0.5 oz/ft — legacy small systems
- R-22 — 1/2" Line Charge — 0.9 oz/ft — legacy standard residential
Frequently Asked Questions
How much refrigerant do I add per foot of lineset?
It depends on refrigerant and liquid line diameter. For R-410A: 0.6 oz/ft for 3/8" line, 1.1 oz/ft for 1/2" line, 1.7 oz/ft for 5/8" line. For R-22: 0.5 oz/ft for 3/8" line, 0.9 oz/ft for 1/2" line. Always verify with the equipment installation manual for your specific model.
What is the factory charge length?
Most split system manufacturers pre-charge the unit for a specific lineset length, typically 15–25 ft. Any lineset beyond this requires additional charge. The factory charge length and charge rate are published in the equipment installation manual.
How do I verify the charge is correct after adding?
After adding the calculated charge, verify with superheat and subcooling measurements. For TXV/EEV systems, check subcooling at the condenser outlet (target: 10–15°F). For fixed-orifice systems, check suction superheat (target: 8–12°F at the evaporator outlet). Pressure alone is not sufficient for charge verification.