Komatsu PC500LC-10R, Shop Manual, Page: 119 / 758

FUNCTION OF OVERHEAT PREVENTION SYSTEM
This system prevents overheating by reducing the pump load and by lowering the engine speed when the cool-
ant temperature or the hydraulic oil temperature become too high during operation in order to protect engine
and hydraulic components.
Operating condition
→
Operation and remedy
→
Condition to cancel
Hydraulic oil temperature:
Min. 95 °C
Working mode: Travel
Engine speed: Kept as it is
Travel speed: Slower
Hydraulic oil temperature: Max. 95 °C
When above condition is satisfied, it
is restored to the state before opera-
tion (automatic restoration).
Operating condition
→
Operation and remedy
→
Condition to cancel
Coolant temperature:
Min. 100 °C
or
Hydraulic oil temperature:
Min. 100 °C
Working mode: P, E, ATT-P, or ATT
mode
Engine speed: Kept as it is
Lowers the pump absorption torque
to reduce engine load according to
the torque control signal.
Coolant temperature: Less than
95 °C
Coolant temperature: Less than
95 °C
When above condition is satisfied, it
is restored to the state before opera-
tion (automatic restoration).
Operating condition
→
Operation and remedy
→
Condition to cancel
Coolant temperature:
Min. 102 °C
or
Hydraulic oil temperature:
Min. 102 °C
Working mode: P, E, ATT-P, or ATT
mode
Engine speed: Kept as it is
Lowers the pump absorption torque
to reduce engine load according to
the torque control signal.
Coolant temperature: Less than
102 °C
Coolant temperature: Less than
102 °C
When above condition is satisfied, it
is restored to the state before opera-
tion (automatic restoration).
Operating condition
→
Operation and remedy
→
Condition to cancel
Coolant temperature:
Min. 102 °C
or
Hydraulic oil temperature:
Min. 102 °C
Working mode: B mode
Engine speed: Kept as it is
Alarm monitor: Lights up
Lowers the pump absorption torque
to reduce engine load according to
the torque control signal.
Coolant temperature: Less than
102 °C
Coolant temperature: Less than
102 °C
When above condition is satisfied, it
is restored to the state before opera-
tion (automatic restoration).
Operating condition
→
Operation and remedy
→
Condition to cancel
Coolant temperature:
Min. 105 °C
or
Hydraulic oil temperature:
Min. 105 °C
Working mode: All modes
Engine speed: Low idle
Alarm monitor: Lights up
Alarm buzzer: Sounds
Coolant temperature: Less than
105 °C
Coolant temperature: Less than
105 °C
Fuel control dial: Return to low idle
(MIN) position.
When above conditions are satisfied,
it is restored to the state before oper-
ation (manual restoration).
10 STRUCTURE AND FUNCTION OVERHEAT PREVENTION SYSTEM
PC500LC-10R 10-25