Warming Up Operation; Warming Up In Cold Weather - Hitachi ZX27U-2 Operator's Manual

WARMING UP OPERATION

The normal operating temperature of hydraulic oil is be-
tween 50 and 80 °C (122 and 176 °F). Hydraulic compo-
nents may be seriously damaged if the machine is oper-
ated when the hydraulic oil temperature is below 20 °C (68
°F).
Before starting work, be sure to follow these warm-up
procedures until the temperature of the hydraulic oil
reaches above 20 °C (68 °F).
Warm-Up Procedures:
1. Run the engine at 100 to 200 min
idle speed for 5 minutes.
2. With the engine speed control lever or the engine
speed control dial at the medium position, run the
engine for 5 to 10 minutes.
3. Extend and retract each cylinder several times and
lightly operate the swing and travel motors to warm
up them.

WARMING UP IN COLD WEATHER

IMPORTANT: In case the hydraulic oil temperature is
low, never operate the machine until all
actuator speeds become normal after
warming up operation.
1. Run the engine at intermediate speed for 5 minutes
(longer if the air temperature is extremely low).
2. Do not run the engine at either slow or fast speed
during this time.
3. Extend and retract each cylinder several times and
lightly operate the swing and travel motors to warm
up them.
4. Extend the bucket cylinder to the stroke end. Be sure
not to hold the bucket lever in this position for more
than 30 seconds.
5. Retract the bucket cylinder to the other stroke end. Be
sure not to hold the bucket lever in this position for
more than 30 seconds.
6. Repeat steps 4 to 5 until the bucket cylinder cycle
time becomes normal.
OPERATING THE MACHINE
-1
(rpm) above slow
5-9