OTC 5025 Operating Instructions Manual

655 Eisenhower Drive
Owatonna, MN 55060 USA
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Operating Instructions
for: 5025

Form No. 558648

5025 Diesel Exhaust Fluid (DEF) Refractometer

WARNING! To prevent equipment failure or
damage resulting in personal injury:

Read and follow all warnings in this

•

instruction sheet before operating
this unit. If the operator cannot read
English, operating instructions and
safety precautions must be read

and discussed in the operator’s

native language.

Wear eye protection and protective

•

clothing when working with DEF.
Contact with DEF may cause
personal injury.

Do not drink DEF. If swallowed,

•

give two glasses of water, induce
vomiting, and call a physician.

2

1

1. Prism 4. Mirror tube (holds the reticle scale)

2. Cover plate 5. Eyepiece (focusing ring of diopter)

3. Correction screw

Accessories

Eyeshade Screw driver Plastic dropper
Soft cloth Plastic bottle Pointer

Application

The refractometer is a portable, precision, optical
instrument used for measuring Diesel Exhaust Fluid
(DEF) concentration.

When a liquid sample is placed on the prism, the light
passing through it is bent. The more concentrated the
liquid, the more the light will bend. The refractometer
contains a reticle, or scale, that is enlarged through the
eyepiece to measure this light.

The values on the scale have been established to
evaluate the DEF condition.

3

4

5

Specications

Style: Diesel Exhaust Fluid (DEF)
Size: 27 x 40 x 160 mm (1.06 x 1.57 x 6.3 in.)
Weight: 176 g (0.39 lbs)

Range Resolution

15 – 40% 0.5%

© Bosch Automotive Service Solutions Inc.

The scale without any

liquid on the prism.

Sheet No. 1 of 1

Issue Date: Rev. C, March 3, 2016

The scale with liquid

on the prism.

The reading is taken at

the point the shadow line

crosses the scale.

Operating Instructions Form No. 558648, Sheet 1 of 1, Back

CAUTION: To prevent personal injury, read
and understand all operating instructions
and helpful hints before operating the

refractometer.

2

1

3

4

5

The following instructions outline how to operate the
refractometer. Item numbers refer to the illustration
above.

1. Aim the front end (prism [1] and cover plate [2]
end) of the refractometer toward a bright light.
Adjust the focusing ring of the diopter (5) until
the reticle (scale within the mirror tube) can be
seen clearly.

2. To set the refractometer to a null or zero point :

(a) Open the cover plate.

(b) Place one or two drops of pure distilled water

on the surface of the prism.

(c) Close the cover plate and press it lightly.

(d) Through the eyepiece, observe where the

shadow line falls.

(e) If necessary, use the screw driver provided to

adjust the correction screw (3) and make the
shadow line coincide with the water line.

The refractometer should now have a null point, and
you are ready to begin measuring.

3. Open the cover plate, and use the soft cloth
provided to wipe the water off the surfaces of the
prism and cover plate.

4. Using the plastic dropper, place one or two drops
of the liquid on the prism surface.

WARNING: To prevent personal injury,
use the plastic dropper provided when

measuring DEF.

5. Close the cover plate and press it lightly.

6. After measurements are taken, use the soft cloth
to wipe the liquid completely from the prism
surface and let the surface dry.

CAUTION: To prevent damage to the
refractometer, do NOT use water to wash the

instrument.

7. Replace the refractometer in its case, and store it
in a dry, clean area.

Helpful Hints and Maintenance

• The distilled water and the liquid to be measured
should be at the same temperature.

• The null point should be adjusted once every
30 minutes.

• Clean the prism completely to prevent residual
impurities, which could cause error during
measurements.

• The refractometer is a precision optical
instrument; handle with care. Do NOT touch
the optical surfaces.

• Avoid strong shock during transportation.

Replacement Parts

Replacement Kit No. 560722 contains one each of
the following:

Calibration Screwdriver
Plastic Dropper
Soft Cloth w/ pouch
Distilled Water Bottle
Black Plastic Stick