-60(63%)

-50(60%)

-40(57%)

-30(53%)

-20(49%)

-10(44%)

-5(41%)

+0(38%)

+5(34%)

+10(30%)

+15(25%)

+20(19%)

+25(12%)

F PROPYLENE

GLYCOL

-60(59%)

-50(56%)

-40(52%)

-30(48%)

-20(44%)

-10(39%)

-5(36%)

+0(33%)

+5(29%)

+10(25%)

+15(21%)

+20(16%)

+25(10%)

ETHYLENE

GLYCOL

WATERLINE

F

1.30

1.25

1.20

1.15

Bad

Bad

Good

Support line (781) 890-7440

Technical support: Extension 200; E-mail: support@extech.com

Repair & Returns: Extension 210; E-mail: repair@extech.com

Product specifications subject to change without notice

For the latest version of this User’s Guide, Software updates, and other

up-to-the-minute product information, visit our website: www.extech.com

Extech Instruments Corporation, 285 Bear Hill Rd., Waltham, MA 02451

User's Guide

Battery/Coolant Refractometer with ATC

Model RF40

Introduction

Congratulations

on

the

purchase

of

your

RF40

Battery/Coolant Refractometer with automatic temperature

compensation. This precision optical instrument should be

handled gently; avoid touching the optical surface. Careful

use of this instrument will provide years of reliable service.

Description

1. Eyepiece

2. Mirror tube

3. Adjustment Screw

4. Cover plate

5. Prism

Field of View

Operation

The instrument measures the refractive index of the sample.

1. Zero Adjustment

Place one or two drops of distilled water on the prism.

Close the cover plate and rotate the adjusting screw so

that the light/dark boundary lines up with the “waterline”.

Once the zero adjustment has been completed, clean the

prism with soft cloth

2. Sample Preparation and Reading

To take a sample reading, simply place a few drops of a

sample liquid on the measurement prism at the end of

the instrument. Lower the cover plate onto the sample

and prism. Open the prism cover and place 2 or 3 drops

on the prism. Close the cover so the liquid spreads

across the entire surface of the prism without air bubbles

or dry spots. Allow the sample to remain on the prism for

approximately 30 seconds.

While holding the instrument under a light source, look

through the

eyepiece. The

freezing point of the

liquid or the state of

the battery liquid is

determined by the

intersection of the

boundary of the light

and dark fields

(known as the

shadowline) on the

printed scale. If the scale appears out of focus, the

eyepiece may be adjusted by rotating the knurled portion.

The instrument also features an eye guard to prevent

stray light from entering the eyepiece and causing

reflections.

It may be necessary to adjust the position of the light

source to maximize the contrast of the shadowline. Under

normal conditions, optimal contrast is obtained by holding

the instrument underneath and perpendicular to a light

source.

Once a reading has been taken, wipe dry with a clean

cloth (do not wash or rinse) and place the instrument in

the supplied plastic case. Store the instrument in a safe,

dry environment.

Temperature is one of the single most important factors

influencing accurate refractometer readings and is one of

the largest sources of error in measurement.

Temperature compensation relieves the user of the

responsibility to measure temperature and apply a

correction factor when taking readings. This

refractometer makes this correction automatically. When

ambient temperature varies from 68°F (20°C), readings

are automatically adjusted to compensate for

temperature variance between 50°F to 86°F (10°C to

30°C).

Specifications

Range

-60 to 32°F for Propylene and

Ethylene glycol freeze point

1.15 to 1.30 specific gravity of battery acid

Resolution

2°F glycol freeze point

0.01 specific gravity of battery acid

Dimensions

6.2x1.6x1.2" (160x40x30mm)

Weight

7.0 oz. (200g)

Calibration and Repair Services

Extech offers complete repair and calibration services for

all of the products we sell. For periodic calibration or repair of

this Extech product, call customer service for details on

services available. Extech recommends that calibration be

performed on an annual basis to ensure calibration integrity.

Warranty

EXTECH INSTRUMENTS CORPORATION warrants this instrument to be free of defects

in parts and workmanship for one year from date of shipment (a six month limited

warranty applies to sensors and cables). If it should become necessary to return the

instrument for service during or beyond the warranty period, contact the Customer

Service Department at (781) 890-7440 ext. 210 for authorization or visit our website

www.extech.com for contact information. A Return Authorization (RA) number must be

issued before any product is returned to Extech. The sender is responsible for shipping

charges, freight, insurance and proper packaging to prevent damage in transit. This

warranty does not apply to defects resulting from action of the user such as misuse,

improper wiring, operation outside of specification, improper maintenance or repair, or

unauthorized modification. Extech specifically disclaims any implied warranties or

merchantability or fitness for a specific purpose and will not be liable for any direct,

indirect, incidental or consequential damages. Extech's total liability is limited to repair or

replacement of the product. The warranty set forth above is inclusive and no other

warranty, whether written or oral, is expressed or implied.

Copyright © 2009 Extech Instruments Corporation

All rights reserved including the right of reproduction

in whole or in part in any form.

Version 3.0 January 2009