PT2E-3381

CO2 Monitor

CO2RK-Lite
Operating ManualContents

Contents
1. Product Overview .........................................................................................................................................................4
1-1. Introduction .........................................................................................................................................................4
1-2. Intended use .......................................................................................................................................................5
1-3. DANGER, WARNING, CAUTION, and NOTE ...................................................................................................6
1-4. Checking markings .............................................................................................................................................7
2. Important Safety Information ........................................................................................................................................8
2-1. Warning information............................................................................................................................................8
2-2. Caution information.............................................................................................................................................92-3. Radio law certification ...................................................................................................................................... 10
2-4. Installation precautions .................................................................................................................................... 13
3. Product Configuration ................................................................................................................................................ 15
3-1. Main unit and standard accessories ................................................................................................................ 15
3-2. Part names and functions ................................................................................................................................ 16
3-3. Display ............................................................................................................................................................. 18
4. Usage Instructions ..................................................................................................................................................... 20
4-1. Turning the power on and off ........................................................................................................................... 20
4-2. Checking the carbon dioxide concentration (LCD display) ............................................................................. 21
4-3. Turning the buzzer on and off .......................................................................................................................... 22
4-4. Checking the peak reading and changing alarm setpoints ............................................................................. 22
5. Functions ................................................................................................................................................................... 24
5-1. Alarm activation (Ventilation alert function) ..................................................................................................... 24
5-2. Fault alarm activation....................................................................................................................................... 25
5-3. Automatic adjustment function ........................................................................................................................ 26
5-4. Smartphone app .............................................................................................................................................. 27
6. Storage and Disposal ................................................................................................................................................ 28
6-1. Procedures for storage or when not in use for extended periods ................................................................... 28
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Contents
6-2. Product disposal .............................................................................................................................................. 28
7. Troubleshooting ......................................................................................................................................................... 29
8. Product Specifications ............................................................................................................................................... 31
8-1. Specifications list ............................................................................................................................................. 31
8-2. Product warranty.............................................................................................................................................. 32

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1. Product Overview

1-1. Introduction

1

Product Overview
1-1. Introduction
Thank you for purchasing the CO2RK-Lite (“the product” hereinafter).
This operating manual describes how to use the product correctly. Make sure you read and fully understand all theinformation provided in this operating manual before use.
The contents of this operating manual are subject to change without notice to allow product improvements. Any
unauthorized duplication or reproduction of this operating manual is prohibited, whether in whole or in part.
Regardless of the warranty period, Riken Keiki does not accept any liability for accidents or damage resulting fromuse of the product.
Be sure to read the warranty policy set forth on the warranty.

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1. Product Overview

1-2. Intended use

1-2. Intended use
The product is designed to monitor carbon dioxide concentrations in indoor environments. The product displays
carbon dioxide concentrations on the LCD screen and alerts the user via the LCD screen color (green, orange, orred) and a buzzer if carbon dioxide concentrations reach alarm setpoints set within the detection range (ventilation
notification concentrations).
The product incorporates a nondispersive infrared absorption (NDIR) sensor. The sensor reacts directly to carbon
dioxide concentrations within indoor environments. It adopts a measurement principle unaffected by interference fromsterilizing alcohol such as ethanol.
The product is available in both Bluetooth® and non-Bluetooth® models. The Bluetooth® model allows viewing ofcarbon dioxide concentrations on the app screen of smartphones or other devices.
Check the markings on the model as described in ‘1-4. Checking markings’ to confirm the product version before use.
The product is not an analyzer designed to perform quantitative analysis/measurement or qualitative analysis ofgases. Use it appropriately for your intended purposes.

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1. Product Overview

1-3. DANGER, WARNING, CAUTION, and NOTE

1-3. DANGER, WARNING, CAUTION, and NOTEThis operating manual uses the following categories to indicate potential damage/hazards if the user disregards theinformation provided and uses the product incorrectly:

DANGER

This indicates situations in which improper handling may result in fatal or
serious injury or significant property damage.
This indicates situations in which improper handling may result in serious

WARNING injury or significant property damage.
CAUTION

This indicates situations in which improper handling may result in minor
injury or minor property damage.

Additionally, usage recommendations are indicated as follows:

NOTE

This indicates items that will be helpful to know when using the product.

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1. Product Overview

1-4. Checking markings

1-4. Checking markings
The nameplate affixed to the product provides various markings (CE/UKCA marking, FCC ID, technical compliancemarking). Check the actual product specifications before use. For CE/UKCA marking models, please refer to the‘Declaration of Conformity’ provided at the end of this manual.
Bluetooth® model

Nameplatelocation

FCC ID
Technical compliancemarking
Non-Bluetooth® model

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CE/UKCA
marking

2. Important Safety Information

2-1. Warning information

2

Important Safety Information
To maintain product performance and to ensure safe use, always observe the following WARNING and CAUTION
instructions:

WARNING If an abnormality is discovered in the product, contact Riken Keiki immediately. Visit our website for
information on the nearest Riken Keiki office.
Website: https://www.rikenkeiki.co.jp/

2-1. Warning information
WARNING Do not pull, clamp, twist, or otherwise apply stress to the cable.
 Do not disassemble or modify the product. Any attempt to disassemble or modify the product will void
product performance guarantees.
 Use the product only as described in this operating manual.
 Do not use the product with control devices or other equipment.
 Use the AC adapter provided.
 The product is available in both Bluetooth® and non-Bluetooth® models.
For information on Bluetooth® wireless communication, refer to ‘2-3. Radio law certification’.
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2. Important Safety Information

2-2. Caution information

2-2. Caution information
CAUTION Do not use walkie-talkies or other radio transmitting devices near the product or its cables. Use of suchdevices near the product may affect measurements.
 The product may not function correctly if the power is turned on once again within five seconds after turning
it off.
 Do not poke the sensor or buzzer sound opening with sharp or pointed items. Doing so may result in
malfunctions or damage to the product, preventing accurate measurements.
 Do not allow the product to come into contact with water. Do not install the product in locations where it may
be exposed to water. The product is not waterproof or splashproof. Exposure to water will result in
malfunctions.
 The product is a precision device. Do not subject the product to strong impact or vibration such as bydropping.
 Avoid contact with internal components after opening the case.
 Do not block the sensor vent.

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2. Important Safety Information

2-3. Radio law certification

2-3. Radio law certification
This product is certified as complying with radio laws in individual countries and regions as follows.
The following actions are prohibited by radio laws. The user and/or retailer may be subject to punishment if prohibited
actions are committed.
・ Use in countries or regions in which radio law certification has not been obtained・ Sale in countries or regions in which radio law certification has not been obtained・ Disassembly or modification of the product・ Removal of certification labels from the product
If this product is used aboard marine vessels, the radio laws of the country bordering the territorial waters shall apply.
In such cases, use shall be prohibited in countries or regions in which radio law certification has not been obtained.
Check to confirm that industrial, scientific, and medical equipment (e.g., microwave ovens), on-premises radio
stations for mobile identification used in plant manufacturing lines (radio stations requiring a license), and specified
low-power radio stations are not operated in the frequency band (2.4 GHz) used by the product. If the product causes
radio interference to a radio station for mobile identification, take measures to eliminate radio interference—for
example, using the product in a different location or stopping radio emissions.
The countries where wireless communication can be used vary depending on the specifications.Please check thenameplate attached to the product.
Wireless specifications
Wireless
communication

Protocol:Version:Frequency:
Modulation:
Output:Bluetooth Low Energy
Ver. 4.2
2,402 - 2,480 MHz
FSK
Maximum 6 dBm

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2. Important Safety Information

Radio lawcertification(Country/region)
Radio Act
(Japan)2-3. Radio law certification

Details

This product contains radio equipment certified to comply with technical standards inaccordance with the Radio Act. Accordingly, a radio station license is not required whenusing this product.

Construction design certification number: 001-A07864
Wireless frequency: 2,402 MHz - 2,480 MHz
Maximum wireless output: 6 dBm
RE Directive(EU Countries)

FCC compliance(United States)

We declare that this equipment complies with the basic requirements of Directive
2014/53/EU and other relevant provisions. Connect to the network with radio waves offrequency 2.4 GHz band and maximum output 6dBm.
This device complies with part 15 of the FCC Rules. Operation is subject to the following
two conditions: (1) This device may not cause harmful interference, and (2) this device
must accept any interference received, including interference that may cause undesired
operation.
FCC CAUTION
Changes or modifications not expressly approved by the party responsible for compliance
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2. Important Safety Information

2-3. Radio law certification

could void the user’s authority to operate the equipment.
Note: This equipment has been tested and found to comply with the limits for a Class A
digital device, pursuant to part 15 of the FCC Rules. These limits are designed to provide
reasonable protection against harmful interference when the equipment is operated in acommercial environment. This equipment generates, uses, and can radiate radio
frequency energy and, if not installed and used in accordance with the instruction manual,
may cause harmful interference to radio communications. Operation of this equipment in a
residential area is likely to cause harmful interference in which case the user will be
required to correct the interference at his own expense.
This equipment complies with FCC radiation exposure limits set forth for an uncontrolledenvironment and meets the FCC radio frequency (RF) Exposure Guidelines. Thisequipment has very low levels of RF energy that is deemed to comply without testing ofspecific absorption rate (SAR).

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2. Important Safety Information

2-4. Installation precautions

2-4. Installation precautions
Be sure to observe the following precautions when installing the product.
Failure to comply with these precautions may result in product failure or improper monitoring.

CAUTION
The product is a precision device. The specified performance may not be achieved depending on the location(environment) in which the product is installed. Check the installation location environment and implement
appropriate remedial measures where necessary.
Do not install the product in the following locations: Locations subject to direct sunlight or outdoors
 Locations exposed to water, oil, chemicals, or dust
 Locations exposed to drafts from air conditioning or other sources Locations exposed to soot, smoke, or steam Locations below 0 °C, over 40 °C, or subject to sudden temperature fluctuations
 Humid locations such as bathrooms or locations subject to condensation
 Poorly ventilated locations such as behind curtains or other objects
 Locations where corrosive gas is present

NOTE
Keep the measurement unit away from doors, windows, and vents and at least 50 cm away from people.
* Taken from Ministry of Health, Labour and Welfare ‘Winter ventilation methods for improving poorly-ventilated
enclosed spaces’ (published November 27, 2020)13 / 32

2. Important Safety Information

2-4. Installation precautions<Do not install the product in locations subject to vibration or impact.>
The product contains precision electronic components. Install the product in a stable location
free of vibration, impact, and risk of falling.

<Do not install in locations exposed to water, oil, or chemicals.>
Avoid installing in locations where there is a risk of splashing water, oil, chemicals, or otherliquids.

<Do not install in locations where temperatures can fall below 0 °C or exceed
40 °C.>The operating temperature range for the product is between 0 °C and 40 °C. Install in alocation where temperature is stable and does not exceed the operating temperature range
during use.

<Do not install in locations subject to direct sunlight or sudden temperaturechanges.>
Avoid locations subject to direct sunlight or radiant heat (infrared radiation from hightemperature bodies) and locations subject to sudden temperature changes. Condensation
may form inside the product, or the product may be unable to adjust to sudden temperaturefluctuations.

<Install away from noise-emitting devices (main unit and cables).>
Avoid installing in locations where high-frequency or high-voltage devices are present.

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3. Product Configuration

3-1. Main unit and standard accessories

3

Product Configuration
3-1. Main unit and standard accessories
Unpack and check the product and accessories.
If anything is missing, contact Riken Keiki.

<Main unit and standard accessories>
Main unit
CO2RK-LiteStandard accessories
AC adapter

Inspection report:
×1

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Product warranty:
×1

Operating manual:
×1

3. Product Configuration

3-2. Part names and functions

3-2. Part names and functions
This section describes the names and functions of the various parts of the product and the LCD display.

(8)
(2)

(3)
(5)

(4)

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3. Product Configuration

3-2. Part names and functions

Name

Main function(1) Power switch

Turns the power on and off. Slide upward to turn the power on, and slide downward toturn the power off.

(2) MODE button

Use this button to cancel a setting while making settings.

(3) △ button

Used to select the PEAK/1st alarm value/2nd alarm value display
Used to select the screen when making settings and to increment input values(4) ▽ button

Used to select the screen when making settings and to decrement input values(5) SET button

Used to confirm a setting when making settings(6)

Buzzer soundopening(7) Sensor(8)

Emits operating and judgment sounds. (Do not block.)
Detects the detection target gas. The sensor is located behind the cover.
(Do not block.)Stand attachment
Used to insert and secure the standholes

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3. Product Configuration

3-3. Display

3-3. Display
(2)

(4)

(3)

(1)
(5)

(6)

(7)

(8)

Name

(9)

(10)

Main function(1)

Operating status icon

Indicates the operation status. Blinks when normal.

(2)

1st alarm icon

Lights up or blinks when a 1st alarm occurs.

(3)

2nd alarm icon

Lights up or blinks when a 2nd alarm occurs.

(4)

Fault alarm icon

Lights up when a fault alarm occurs.

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3. Product Configuration

3-3. Display(5)

Concentration display
Maintenance display

Displays carbon dioxide concentrations.
Displays maintenance items when making settings.

(6)

Units display

Displays the units (ppm).

(7)

Gas name display
Maintenance display

Displays the gas name. [CO2] is displayed.
Displays item names when making settings.

(8)

Power supply indication

Lights up when the power is turned on.

(9)

Not used with this product(10)

Buzzer on/off icon

Lights up when the buzzer is turned off (muted).

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4. Usage Instructions

4-1. Turning the power on and off

4

Usage Instructions
4-1. Turning the power on and off
・ Before turning on the power switch, check to confirm that the product has been correctly installed.
・ Slide the power switch up to turn on and down to turn off.
ON
Power on▼▼▼Initialization(approximately 25 seconds)▼▼▼
Measurement screen

OFF

CAUTION Never turn the power off during initialization. Doing so may result in malfunctions.
 When using the product for the first time or after storing for extended periods, place outdoors or in a wellventilated location with the power turned on for at least 24 hours to allow time for the automatic adjustment
function to activate.
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4. Usage Instructions

4-2. Checking the carbon dioxide concentration (LCD display)

4-2. Checking the carbon dioxide concentration (LCD display)
The measurement screen displays the carbon dioxide concentrationon the LCD.
The product is capable of monitoring carbon dioxide at concentrations
from 400 ppm to 5,000 ppm.
If the concentration is below 400 ppm, the display will remain fixed at
400 ppm. Likewise, if the concentration exceeds 5,000 ppm, thedisplay will remain fixed at 5,000 ppm.

CAUTION Atmospheric carbon dioxide concentrations outdoors may vary from region to region. Readings will constantly
fluctuate within the range from 400 ppm to 450 ppm. A constant carbon dioxide concentration reading may
indicate a product malfunction.
 To confirm that the product is operating correctly, expose to outdoor air out of direct sunlight, wind and rain,
dust, or human exhaled breath. The product can be assumed to be operating correctly if the carbon dioxide
concentration is within the range from 400 ppm to 450 ppm after five to ten minutes.

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4. Usage Instructions

4-3. Turning the buzzer on and off

4-3. Turning the buzzer on and off
Hold down the SET button for at least three seconds to turn off (mute) or on (unmute) the buzzer.
Once the buzzer is turned on or off, this state is retained even when the power is turned off.

SET button

BuzzerON/OFF icon

4-4. Checking the peak reading and changing alarm setpoints
Use the △ button to check and clear the peak value, check and alter the 1st alarm setpoint, check and alter the 2nd
alarm setpoint, and to select individual screens. The default concentration for the 1st alarm setpoint is 1,000 ppm,
based on the Building Environmental Sanitation Management Standards (JAPAN). The default concentration for the
2nd alarm setpoint is 1,500 ppm, based on the School Environmental Sanitation Management Standards (JAPAN).
These alarm setpoints can be changed according to each country or customer's standard.

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4. Usage Instructions

4-4. Checking the peak reading and changing alarm setpoints△ button

Measurement screen
Press the △ button to select the peak value confirmation screen.

Peak value confirmation screen
Press the △ button to select the 1st alarm setpoint confirmation screen.
Hold down the SET button for at least three seconds to clear the peak value currently
saved.
The peak value is also cleared when the power is turned off.
1st alarm setpoint confirmation screen
Press the △ button to select the 2nd alarm setpoint confirmation screen.
Press the SET button. The value will blink to indicate the 1st alarm setpoint can bealtered.
Press the SET button while the value is blinking to enter and save the value.
2nd alarm setpoint confirmation screen
Press the △ button to return to the measurement screen.
Press the SET button. The value will blink to indicate the 2nd alarm setpoint can bealtered.
Press the SET button while the value is blinking to enter and save the value.
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5. Functions

5-1. Alarm activation (Ventilation alert function)

5

Functions5-1. Alarm activation (Ventilation alert function)
The product notifies the user via the following alarm indications when carbon dioxide concentrations reach the values
set for the alarm setpoints:<When 2nd alarm setpoint is exceeded><When 1st alarm setpoint is exceeded>
・ The LCD backlight lights up in orange.
・ The [ALM1] icon at the top of the LCD blinks.
・ The buzzer blips twice.
* Press any button to stop just the buzzer.

・ The LCD backlight lights up in red.
・ The [ALM1] and [ALM2] icons at the top of the LCD
blink.
・ The buzzer blips three times.
* Press any button to stop just the buzzer.

The alarm will be automatically reset once the carbon dioxide concentration falls below the reset concentration(50 ppm below the concentration set as the alarm setpoint).
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5. Functions

5-2. Fault alarm activation

5-2. Fault alarm activation
The following alarm indications are triggered if a product abnormality is detected.
An error message will appear on the LCD. Check the error message and take the appropriate corrective action.

<When a fault is detected>
・ The LCD backlight lights up in red.
・ The [FAULT] icon blinks at the top of the LCD.
・ The buzzer blips three times.
* Press any button to stop just the buzzer.
After the product has successfully recovered from the fault, it restarts with the process normally performed right after
it is turned on (initialization).
If the problem lies with the product and the fault occurs repeatedly, contact Riken Keiki immediately.

NOTE
For more information on malfunctions (error messages), refer to ‘7. Troubleshooting’.

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5. Functions

5-3. Automatic adjustment function

5-3. Automatic adjustment function
The product features an automatic adjustment function that corrects sensor output fluctuations over time.
This records the lowest carbon dioxide concentration measured during the 24-hour period since the product was
turned on. It corrects this to correspond to a 420 ppm carbon dioxide concentration in the outdoor atmosphere. If thepower is subsequently left on, the lowest carbon dioxide concentration measured during the next seven-day period isrecorded. This value is corrected to correspond to a 420 ppm carbon dioxide concentration in the outdoor
atmosphere.

CAUTION The outdoor atmospheric carbon dioxide concentration may vary from region to region but is normally within
the range from 400 ppm to 450 ppm.
 The product must be installed in a location where the carbon dioxide concentration of the indoor air falls toapproximately the same 420 ppm as the outdoor air at night, such as at weekends. If the lowest carbon dioxide
concentration is not 420 ppm during this period, this difference will be regarded as the margin of error.
 The automatic adjustment function will not operate reliably if the power is turned on and off frequently.
 To correct sensor output fluctuations over time, turn off the power, then turn the power back on to activate theautomatic adjustment function 24 hours later.
 If the product reading does not vary from 400 ppm in a room where several people are present or if the reading
remains high (for example, over 1,000 ppm) where few people are present, the adjustment may not haveoccurred. Turn off the power, then turn the power back on again to activate the automatic adjustment function
24 hours later.

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5. Functions

5-4. Smartphone app

5-4. Smartphone app
The product uses Bluetooth® to allow monitoring of carbon dioxide concentrations from a smartphone. Download
and install the dedicated free RK Link app from Google Play or the App Store to use this function.
RK Link includes an email sending function using Gmail. A Google account (Gmail address) is required to use this.
For more information, refer to the separate RK Link operating manual.

Google Play StoreApple App Store

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6. Storage and Disposal

6-1. Procedures for storage or when not in use for extended periods

6

Storage and Disposal
6-1. Procedures for storage or when not in use for extended periods
The product must be stored in the following environment:
・ At normal temperature and humidity in a location not exposed to strong light (e.g., direct sunlight)
・ In a location free of gases, solvents, and vapors
Store the product in its shipping carton, if retained and available.
If the shipping carton is no longer available, store the product away from dust, etc.

6-2. Product disposal
Dispose of the product as industrial waste (incombustible) in accordance with local regulations.

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7. Troubleshooting

7

TroubleshootingThis troubleshooting section does not address causes of all problems that may occur with the product. It provides
brief explanations to assist in determining the causes of common problems.
If you encounter symptoms not addressed here or if problems persist even after taking corrective action, contact
Riken Keiki.
Symptom/display

The power cannot
be turned on.

Abnormal operation

Cause

ActionThe power switch isturned off.

Turn the power switch ON.

Cable abnormality(break, unconnected,
short)

Check the wiring for this product and for related devices.

The AC adapter isdefective.

The AC adapter must be replaced.
Contact Riken Keiki.

The AC adapter is notcorrectly connected.

Connect the AC adapter correctly.

Effects of radio waves,etc.

Turn off the power and restart.
If similar symptoms recur frequently, take appropriate
measures to address the noise source.
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7. Troubleshooting
Symptom/display

Cause

ActionSensor abnormality
E-1 SENS

Sensor abnormality

System abnormality
E-9 SYSTEM

Internal ROM, RAM, orContact Riken Keiki.
EEPROM abnormalities

The reading does
not stabilize.

A sensor abnormality has occurred.
Contact Riken Keiki.

Sudden temperaturefluctuations

Install the product in a location free of sudden temperaturefluctuations, such as where exposed to air-conditioning
drafts or open windows.

Carbon dioxide
concentration
fluctuations

Both heating equipment and human respiration generatehigh concentration carbon dioxide. Avoid installing in suchlocations.

Microwave ovens and other large domestic electrical
Effects of external noise appliances may generate powerful electromagnetic radiation.
Avoid installing in such locations.

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8. Product Specifications

8-1. Specifications list

8

Product Specifications
8-1. Specifications list
Detection principle
Detection target gas
Detection range
Display accuracy(for identical conditions)
Display function
Alarm setpoints
Alarm pattern
Power source
Power consumption
Operating temperature range
Operating humidity range
External dimensions
WeightNondispersive infrared absorption method (NDIR)
Carbon dioxide (CO2)400 - 5,000 ppm±50 ppm ± 5 % reading (standard conditions: 25 °C, 1 atmosphere)
LCD digital display (with 3-color backlight: green, orange, and red)
1st: 1,000 ppm / 2nd: 1,500 ppm (default setting)1st: Backlight lights up (orange), buzzer sounds
2nd: Backlight lights up (red), buzzer sounds* By default, the buzzer is set to on.
100 - 240 V AC ± 10 %, 50/60 Hz
Maximum 5 VA (100 V AC), 8 VA (240 V AC)
0 - 40 °C (no sudden fluctuations)
Up to 90 %RH (no condensation)
Main unit: Approximately 80 (W) × 120 (H) × 38.5 (D) mm
Approximately 180 g

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8. Product Specifications

8-2. Product warranty

8-2. Product warranty
1. One year from date of purchase provided the product is used correctly and in accordance with the operating
manual and all other warnings and instructions.
2. No after-sales maintenance or other service is provided for this product.
3. In the following cases, a fee will be charged for repairs or replacement, even within the warranty period:(a) The defect or damage is as the result of erroneous operation, unwarranted repair, or modification.
(b) When faults or damages are due to the item being repaired or modified at service agencies other than RIKEN
KEIKI or service agencies designated by RIKEN KEIKI.
(c) When the faults or damages are due to the item being incorrectly moved, transported, toppled, dropped, or
stored after the product was purchased.
(d) When the faults or damages are due to external factors such as; acts of providence such as fire, earthquake,flood, lightning strikes, etc.; pollution; abnormal voltage; use of power sources outside of rated ranges (voltage,
frequency); etc.
(e) When the cause of the fault is something other than this product.

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Revision History
Issue

Revision details

0First issue

1

Correction : CE Declaration of Conformity,
Addition : UKCA Declaration of Conformity

Issue dateNovember 12, 2021
July 11, 2022