The refrigerant line carrying low-pressure vapour from the evaporator back to the compressor.
The suction line is the larger, insulated line on a split system. Horizontal runs are pitched toward the compressor, and vertical risers are sized so vapour velocity carries oil upward, with traps where the design calls for them. See oil return.
Exam work areas
B · Tools, piping and refrigerant handling D · Installing systems and controls