Komatsu HM400-5, Operation & Maintenance Manual

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NOTICE
• Foreign materials in the DEF system or urea deposits caused by precipitation of urea may hinder
operation of the devices.
• Do not disassemble any devices of the DEF System other than the filter for change. Do not modify
any devices of the DEF System.
• Paint may cause deterioration of the devices. When painting the surrounding areas, take care not to
get any paint on the injector and the supply pump.
• Always use DEF that conforms to the quality standard. If any additional additive agents or water is
mixed in DEF and that mixture is used, the devices will not function properly, and conformance to
the exhaust gas regulations will be lost. In addition, it may cause failures in the engine system. If
DEF out of the standard is filled or used by mistake, contact your Komatsu distributor.
About the operation of Urea SCR system
The Urea SCR System automatically starts operating as soon as the engine is started.
Even after the engine starting switch is turned to the OFF position, the devices will still be in operation for sever-
al minutes to purge any DEF in the lines, the injector and the supply pump back to the DEF tank. It does not
indicate any abnormality. When DEF has been returned to the tank, the devices stop.
Do not turn OFF the battery disconnect switch while the devices are still in operation. When the devices com-
plete their shutdown process, the system operating lamp will go out, and the battery disconnect switch may be
disconnected.
About the operation in cold weather
DEF freezes at –11 °C.
Urea SCR system is equipped with a heating system to thaw frozen DEF once it is frozen, for example, during
parking and to prevent DEF from freezing during operation.
In case DEF freezes during parking, once the engine starts running the heating system automatically starts pro-
viding heat to thaw frozen DEF. The pump and the injector start working only after a proper amount of DEF is
thawed. This may be noticed as a delay in the start of functioning of the pump and the injector.
The heating system is also activated automatically during operation to prevent DEF from freezing whenever the
ambient temperature drops below a certain threshold where DEF in the system may freeze. In the event that the
ambient temperature drops further than a temperature where the heating system is capable of maintaining fluidi-
ty of DEF, the DEF system automatically starts purging the remaining DEF back to the tank and stops pumping
and injection while heating continues. Once the ambient temperature rises above a temperature where DEF
system becomes functional, it resumes operation automatically.
Short duration of white plume given off from the tail pipe may be visible at and shortly after engine start-up in
cold weather, but this is not malfunction.
Inducement strategy when the DEF tank Level becomes low
When the amount of DEF in the tank goes low, the Inducement strategy will be activated.
If Inducement starts, add DEF to the DEF tank immediately.
The DEF level caution lamp (1) on the monitor lights up, the audible alert starts, and the Action level is dis-
played, and Inducement strategy is activated. Inducement strategy includes engine output deration, speed limi-
tation, or other warning actions intend to prompt the operator to maintain or repair SCR system.
The Inducement strategy progresses in 4 levels from Warning, Continuous Warning, Low level Inducement and
Severe Inducement.
OPERATION EXPLANATION OF COMPONENTS
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