Komatsu PC308USLC-3E0 Operation & Maintenance Manual page 154

MACHINE OPERATIONS AND CONTROLS MACHINE OPERATIONS AND CONTROLS
18. Check that hydraulic oil temperature monitor (7) is displaying
green.
If the hydraulic oil temperature monitor is not displaying green
(it is displaying white), repeat Steps 6 to 10 until the display is
green.
If the hydraulic oil temperature monitor displays green, the hydraulic equipment warm-up operation is completed.
After confirming that the hydraulic oil temperature monitor displays green, carry out the following procedure.
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OPERATION OPERATION