Linesets

Linesets are the paired copper tubes that connect the outdoor condenser unit to the indoor evaporator coil in split-system air conditioning and heat pump installations. The system uses a liquid line (smaller diameter) and a suction line (larger diameter), typically equipped with thermal insulation and service ports for charging and maintenance.

Function: The liquid line carries high-pressure liquid refrigerant from the condenser to the evaporator, where it expands and absorbs heat. The suction line returns low-pressure gas from the evaporator to the compressor. Together they enable heat transfer and circulation of refrigerant through the system.

Construction and installation: Linesets are usually made of copper tubing and are insulated to minimize heat gain or loss and prevent condensation. They are routed between units with attention to bends, support, and protection from physical damage. Proper slope helps ensure oil returns to the compressor, and the overall length and diameter must match the equipment’s refrigerant charge and capacity. Before charging, the line set is purged and evacuated; some installations use pre-charged line sets that include refrigerant for a specified length.

Types and compatibility: Line sets vary by refrigerant type and unit, and some systems use factory-charged line sets that come pre-filled for a particular length. Mini-split systems, multi-split systems, and traditional central air systems all use linesets, though connector sizes and configurations differ.

Maintenance: Visual inspection for insulation damage, leaks, and corrosion is common. If a refrigerant leak is suspected, the system should be inspected and serviced by a licensed technician.