Case 621F Service Manual Download

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1002-6

What is Selective Catalytic Reduction (SCR)

The main components of the SCR system include the
SCR catalyst, the Diesel Exhaust Fluid (DEF)/
AdBlue® injection unit, the DEF/AdBlue® tank, and
the DEF/AdBlue® dosing control unit.

How does Selective Catalytic Reduction
(SCR) work?

During combustion, harmful Nitrogen Oxide (NOx)
molecules are formed in the exhaust. By injecting a
DEF/AdBlue® solution into the exhaust prior to a
catalyst, the NOx can be converted to harmless
elemental Nitrogen and water. This happens when
the NOx molecules react inside the catalyst with the
heat generated by the engine and the ammonia in
the DEF/AdBlue® solution.

During cold engine operation at low engine coolant
and ambient air temperatures, water vapor will be
visible from the exhaust when the engine operates.
This water vapor will resemble steam or light white
smoke and will dissipate as the engine and machine
components warm and is considered normal.

NOTE:

After engine shutdown, the SCR system will

perform a purge cycle, which permits the supply

module to continue to run for up to 70 seconds. This

is to be considered normal and requires no action

from the operator.

What is Diesel Exhaust Fluid
(DEF)/AdBlue®?

DEF/AdBlue® is a non-toxic aqueous urea solution (

3 2 . 5 %

) w i t h a s l i g h t a m m o n i a o d o r u s e d t o

chemically reduce NOx emissions from heavy-duty
diesel powered vehicles.

DEF/AdBlue® is neither explosive nor harmful to the
environment and is classified under the minimum-risk
category of transportable fluids. DEF/AdBlue®
quality is defined by ISO 22241-1. The

American Petroleum Institute (API®)

has a

voluntary certification program for DEF/AdBlue®. To
ensure DEF/ AdBlue® satisfies the requirements of
ISO 22241. DEF/AdBlue®. API Diesel Exhaust Fluid
Certification Mark is a registered trademark of API in
the United States and or other countries.

Storage, handling, and transport

NOTICE:

Storage temperatures above

30 °C

(

86 °F

)

greatly reduce the shelf life of DEF/AdBlue®.

DEF/AdBlue® has a typical shelf life of 6-12 months.

Refer to the

HELF LIFE

table below. In order for

DEF/AdBlue® to remain in a usable condition, stor-
age requirements need to be met.

•

Store between

-11 °C

(

12 °F

) and

30 °C

(

86 °F

• Use only an approved DEF/AdBlue® container.

• Keep container tightly closed.

• Keep container in a cool, well-ventilated area.

• Keep away from heat and direct sunlight.

Thawing

• The machine is equipped with an internal tank
heater to thaw frozen DEF/AdBlue®. The machine
will still function until the DEF/AdBlue® begins to
flow. The SCR system will then function normally.

• Do not heat DEF/AdBlue® for long periods of time
at temperatures above

30 °C

(

86 °F

). This causes the

solution to decompose, which very slowly decreases
the expected shelf life.

NOTICE:

Do not use an anti-gelling or freeze point

improver in your DEF/AdBlue®. The

32.5 %

solution

is specifically designed to provide the optimum NOx
reduction properties. Any further blending or adjust-
ing of the DEF/AdBlue® mixture will lessen its ability
to perform correctly and may cause damage to the
SCR components.

Handling and supply of additives, if any.

• Personal Protective Equipment (PPE) is not
required under normal conditions. If splashing is
likely, wear eye protection. For prolonged or repeated
contact, impervious gloves are recommended.
F ollow th e pre cau tion s list ed in th e SAFET Y
INFORMATION chapter when handling any service
fluid.

• No additives are required.

NOTICE:

Contaminated DEF/AdBlue® can affect the

performance of your machine. Follow all instructions
in this manual when handling DEF/AdBlue®.

Shelf life

Constant ambient storage temperature and

minimum shelf life

Less than or equal to

10 °C

(

50 °F

) 36 months