Preheater Does Not Operate - Komatsu Galeo PC800-8 Shop Manual

40 Troubleshooting
E-2 Preheater does not operate
Failure
• Preheater does not operate (1) When starting switch is turned ON, auto-preheater does not work.
phenomenon
• When starting switch is turned ON, HEAT lamp on panel lights up for about 30 seconds and then starts
Relative
blinking to notify completion of preheating.
information
• Check that the starting motor rotates normally in advance.
Defective circuit breaker
1
No. 1 or fuse No. 6, No. 20
Defective starting switch
2
(Internal defect)
Defective auto-preheater
3
relay
Possible causes
and standard
value in normal
state
4 Defective air heater relay
5 Defective air heater
PC800, 850-8
Cause Standard value in normalcy and references for troubleshooting
If a circuit breaker is turned OFF or a fuse is broken, the circuit probably
has grounding fault
aPrepare with starting switch OFF, then hold starting switch OFF and
ON and carry out troubleshooting in each case.
H06 (male)
Between (1) – (5)
aPrepare with starting switch OFF, then carry out troubleshooting with-
out turning starting switch ON.
aPrepare with starting switch OFF, then turn starting switch R1 and
carry out troubleshooting.
1) Between terminal R15 – chassis ground
2) Between terminal R17 – chassis ground
aPrepare with starting switch OFF, then carry out troubleshooting with-
out turning starting switch ON.
3)Between heater relay ground terminal –
chassis ground
If check results of 1) – 3) above are normal, air heater relay is defective.
aPrepare with starting switch OFF, then carry out troubleshooting with-
out turning starting switch ON.
Between terminal (+) – terminal (–)
Starting switch
ON
OFF
R18 (female)
Between (1) – (2)
Between (3) – (5)
Between (3) – (6)
Air heater
SEN00793-02
Resistance
Max. 1 z
Min. 1 Mz
Resistance
100 – 500 z
Min. 1 Mz
Max. 1 z
Voltage 20 – 30 V
Voltage 20 – 30 V
Resistance Max. 1 z
Continuity
Continued
9