Working line
Main flow line carrying working pressure between components (solid line).
ISO 1219-1
Lines and connections
How energy and control signals are routed in a hydraulic circuit diagram.
Pilot (control) line
Carries a control signal (pilot pressure) that operates a valve (long-dashed line).
ISO 1219-1
Drain (leakage) line
Returns internal leakage to the reservoir at no pressure (short-dashed line).
ISO 1219-1
Test yourself on these in the symbol trainer.
Ready for verified competence?
Hydrali Core: Verified Fundamentals combines theory, scenario-based assessment and an oral defence evaluated by a human assessor. The result is a verifiable competence credential issued to the individual.