Hitachi ZW180 Technical Manual page 86

Hydraulic Fan Cleaning Control
Purpose: To clean the radiator and oil cooler by re-
versing the hydraulic fan in order to blow
away dust in case cleaning of the radiator
and oil cooler are needed.
Operation:
1. When the engine is started after the following
conditions exist and the fan reverse rotation
switch is turned ON, the signal is transmitted from
MC to the reverse rotation control solenoid valve.
2. When the reverse rotation control solenoid valve
is operated, the reverse rotation spool is shifted,
and the fan motor rotation is reversed.
3. In reverse rotation, as hydraulic fan cooling con-
trol is not made, the fan speed changes from
maximum to minimum in response to the de-
pressing amount of the accelerator pedal.
4. In case any one of the following conditions are
changed during reverse rotation, the engine
speed is immediately fixed to idle speed.
5. Hydraulic fan cleaning control is not released only
by turning the fan reverse rotation switch OFF.
This control is released by the procedure of turn-
ing the fan reverse rotation switch OFF – turning
the key switch OFF – turning the key switch ON.
6. In case the engine speed is fixed to idle speed,
this control is released by the procedure of turning
the fan reverse rotation switch OFF – turning the
key switch OFF – turning the key switch ON.
Conditions:
•
Fan reverse rotation switch: ON
•
Parking brake switch: ON (Brake is effective.)
•
FNR lever: neutral
•
FNR switch: neutral
SYSTEM / Control System
T2-1-44
NOTE: Temporarily turn the reverse rotation control
solenoid valve ON when the key switch is
turned ON as the spool maybe stuck in
case the reverse rotation control solenoid
valve is not operated for a long time. It is
turned ON once every one minute after the
key switch is turned ON. This operation is
not made during the hydraulic fan cleaning
control.