Kele KCO-NO2 User manual

PRELIMINARY
Kele KCO-NO2
PRELIMINARY
User’s Manual

Kele KCO-NO2 User’s Manual
Last Rev: 6/15/2020 Kele •3300 Brother Blvd. •Memphis, TN 38133 •WWW.KELE.COM Page 2 of 14
PRELIMINARY
CONTENTS
1Specifications.........................................................................................................................................................3
2Mechanical Installation..........................................................................................................................................4
3Electrical Installation .............................................................................................................................................4
3.1 Power Connection........................................................................................................................................5
3.2 Analog Output Connections.........................................................................................................................5
3.3 Relay Connections........................................................................................................................................6
4Operational Description ........................................................................................................................................7
4.1 Startup..........................................................................................................................................................8
4.2 Setting Warning and Alarm Thresholds .......................................................................................................8
4.3 Warning and Alarm Conditions ....................................................................................................................8
4.4 Sensor Readings ...........................................................................................................................................8
5Sensor Calibration..................................................................................................................................................9
5.1 Calibration Gases .........................................................................................................................................9
5.2 Calibration Procedure ................................................................................................................................10
6Sensor Module Replacement...............................................................................................................................12
6.1 Sensor Errors..............................................................................................................................................12
6.2 Field Replacement of Sensor Modules.......................................................................................................12
7Warranty..............................................................................................................................................................13
7.1 Duration .....................................................................................................................................................13
7.2 Limited Warranty and Remedies................................................................................................................13
8Disclaimers...........................................................................................................................................................14
8.1 Inspection and Maintenance......................................................................................................................14
8.2 Life Safety...................................................................................................................................................14

Kele KCO-NO2 User’s Manual
Last Rev: 6/15/2020 Kele •3300 Brother Blvd. •Memphis, TN 38133 •WWW.KELE.COM Page 3 of 14
PRELIMINARY
1 SPECIFICATIONS
Mechanical
Chassis Construction
18 Ga. Grey powder-coated steel. Lockable, hinged or screw-on
cover style available.
Weight
2.0 Lbs
Operating Temperature
-20 to 50°C
Operating Humidity
15 –90 %RH
Storage Temperature
0 to 20°C (to minimize sensor degradation)
Case Dimensions (H x W x D)
6.4” x 5.9” x 2.4” (163.5 x 150.8 x 60.7 mm)
Sensor Housing Diameter
20.4 mm (.8032 “ approx. 13/16”)
Recommended calibration cap diameter
20.5 mm (.807”)
External Indicators
Separate tri-color LEDs indicate operational status of each senor.
TABLE 1: MECHANICAL SPECIFICATIONS
Electrical
Operating Power Voltage
13 to 30 VAC (RMS) or 15 to 45 VDC
Power Consumption
< 5W
Control Relays
Separate SPDT relays for warning and alarm outputs.
10 Amps max at 120 VAC (RMS) or 30 VDC.
Concentration Reporting Outputs
Powered 4 –20 mA current loop output for each sensor.
4 mA output => 0 ppm concentration. 20 mA => full scale output.
Maximum loop resistance: 510Ω
TABLE 2: ELECTRICAL SPECIFICATIONS
Carbon Monoxide Sensor (CO)
Sensor Type
Electrochemical
Measurement Range
0 –100 ppm
Analog Output Range
4mA to 20mA (corresponds to 0 to 100 ppm)
Accuracy
±5% of Full Scale (typical)
Calibration Interval
6 Months
Sensor Life
2 Year typical1
Calibrated Field-Replaceable Sensor
YES
TABLE 3: CO SENSOR SPECIFICATIONS
Nitrogen Dioxide (NO2)
Sensor Type
Electrochemical
Measurement Range
0 –10 ppm
Maximum Permissible Exposure
150 ppm
Analog Output Range
4mA to 20mA (corresponds to 0 to 10ppm)
Accuracy
± 1.5 ppm (typical)
Calibration Interval
6 Months
Sensor Life
2 Year typical1
Calibrated Field-Replaceable Sensor
YES
TABLE 4: NO2SENSOR SPECIFICATIONS
1Exposure to harsh ambient environmental conditions may shorten senor life.

Kele KCO-NO2 User’s Manual
Last Rev: 6/15/2020 Kele •3300 Brother Blvd. •Memphis, TN 38133 •WWW.KELE.COM Page 4 of 14
PRELIMINARY
2 MECHANICAL INSTALLATION
The Model KCO-NO2 is available in two versions of a gray, powder-coated, 18 Gauge steel enclosure. The
removable, lockable, hinged-cover version is shown in Figure 1 and the screw-down cover version is shown in
Figure 2. All electronics are attached to the front cover. There are ½” conduit knock-outs on all sides for electrical
connections. In potentially damp locations the knock-out on the bottom of the case should be used to minimize
the possibility of water entry. DO NOT USE THE VENT HOLES FOR WIRE ENTRY.
This unit is designed to mount to a rigid, vibration-free surface near the middle of the area to be monitored about
5 feet above the floor. It should be located where there is free airflow - avoid corners or recesses. The air vents
on the sides of the enclosure should not be closer than 1 foot from the nearest perpendicular wall and must not be
obstructed or painted-over.
3 ELECTRICAL INSTALLATION
The controller is not equipped with a power switch; it is operational whenever sufficient power is applied to the
power input terminals.
All electrical connections to the controller are made through screw terminals that can be unplugged during wiring.
The controller’s enclosure contains multiple conduit knockouts for flexibility during installation; refer to Figure 1
and Figure 2 for details and dimensions of the enclosures.
FIGURE 1: CO/NO2HINGED FRONT PANEL ENCLOSURE DIMENSIONS
FIGURE 2: CO/NO2SCREW FRONT PANEL ENCLOSURE DIMENSIONS

Kele KCO-NO2 User’s Manual
Last Rev: 6/15/2020 Kele •3300 Brother Blvd. •Memphis, TN 38133 •WWW.KELE.COM Page 5 of 14
PRELIMINARY
3.1 POWER CONNECTION
Power connection to the controller is made at the two-terminal
screw connector located at the bottom-right side of the board
(highlighted in Figure 3). Power to the controller can be either
AC or DC voltage; DC voltage can be connected in either polarity
(see Table 2 for more details).
To wire power:
1. Open the controller’s enclosure and unplug the screw
terminal labeled POWER on the controller board.
2. Attach power wires to the screw terminal ensuring the
connection is snug.
3. Plug the screw terminal back into the POWER
receptacle on the controller board: this will cause the
controller to power up and begin operation.
It is recommended that all wired connections are connected prior to providing power to the controller: see the
following sections for details on making these connections.
3.2 ANALOG OUTPUT CONNECTIONS
Each sensor’s readings are individually reported at the controller’s
two powered 4-20mA analog output connections. Current flows out
of the ‘+’ terminal and returns to the ‘-‘terminal.
The CO output is provided at the terminals highlighted green in
Figure 4 and the NO2output is provided at the terminals highlighted
yellow in Figure 4. The analog output connection has polarity as
labeled on the controller silkscreen: care must be taken to ensure
proper connection. To wire the analog output connections:
1. Power down the controller, this can be done by unplugging
the controller power terminal (Figure 3).
2. Unplug the desired analog output screw terminal (either the NO2or CO terminal).
3. Connect the signal wires paying close attention to the polarity.
4. Plug the analog output screw terminal back into the controller.
5. Repeat this process for both analog outputs, then reconnect power.
FIGURE 3: power connection
FIGURE 4: Location of analog output
terminals.

Kele KCO-NO2 User’s Manual
Last Rev: 6/15/2020 Kele •3300 Brother Blvd. •Memphis, TN 38133 •WWW.KELE.COM Page 6 of 14
PRELIMINARY
3.3 RELAY CONNECTIONS
The controller has two SPDT dry-contact relay output terminals (shown in Figure 5). The relay connections have
three-terminal screw connectors that allow devices to be wired to the controller in either normally-open (NO) or
normally-closed (NC) configuration. These outputs are activated when ambient air concentrations rise above the
controller threshold settings (refer to Section 4.3 for more
information).
In the NO Configuration, the voltage attached to the NO terminal
will be present at the COM terminal only when the relay output is
activated.
In the NC Configuration, the voltage attached to the NC terminal
will be present at the COM terminal while the relay output is
deactivated: the voltage attached to the NC terminal is removed
when the relay output is activated.
An example wiring diagram for relay connections are provided in
Figure 6. When wired as shown, the fan will be energized in both
warning and alarm conditions and the alarm will be energized only
in the alarm condition.
To wire the Warning and Alarm relay outputs:
1. Determine if the device being attached to the relay output
should be wired in NO or NC configuration.
2. Unplug the relay output screw terminal.
3. Connect the power source voltage for the device being
attached to the controller’s relay output to either the NO or
NC location of the screw terminal (Figure 5).
4. Wire the power input of the device being attached to the
controller’s relay output to the COM location of screw
terminal.
5. Plug the relay output screw terminal back into the correct
location on controller board.
Figure 5: Relay Outputs
FIGURE 6: EXAMPLE WIRING DIAGRAM FOR NORMALLY
OPEN OPERATION

Kele KCO-NO2 User’s Manual
Last Rev: 6/15/2020 Kele •3300 Brother Blvd. •Memphis, TN 38133 •WWW.KELE.COM Page 7 of 14
PRELIMINARY
Status LED Color
Operational Status
Description
Concentration is below
the ventilation
threshold. No outputs
are active.
Concentration is above
the ventilation threshold
and below the alarm
threshold. Ventilation
relay is active.
Concentration is above
the alarm threshold.
Both ventilation and
alarm relays are active.
Sensor module in need
of service (refer to
Section 6).
Table 5: Front panel status LED Indications.
4 OPERATIONAL DESCRIPTION
The KCO-NO2 is a ventilation and alarm controller that senses the presence of gasoline or diesel engine exhaust
fumes and operates a Warning contact closure to trigger exhaust fans when elevated levels of carbon monoxide
(generated by gasoline engines and abbreviated CO) or nitrogen dioxide (from diesel engine exhaust and
abbreviated NO2) are detected. If the concentration of either gas exceeds its programmed alarm value, a second
set of alarm contacts is operated to trigger an alarm.
The controller has two independent sensor modules; one for sensing carbon monoxide (CO), the other senses
nitrogen dioxide (NO2). The sensor modules are field replaceable: each sensor module can be replaced with
minimal effort when it reaches end-of-life (EOL) while leaving the main control mounted and wired (refer to
Section 7.1).
The controller has four, factory-preset, pairs of warning and alarm levels for each gas (see Table 8). Each setting
determines both the controller’s warning and alarm
thresholds (see Section 4.2). When the concentration of
either CO or NO2rises above its configured warning
threshold, the WARNING relay output is activated. When
either concentration rises above its alarm threshold, the
controller’s ALARM relay is activated (refer to Section 4.2).
When both the CO and NO2concentrations are below the
warning threshold, the WARNING relay is deactivated; the
same action occurs for the ALARM relay.
The front panel has two LEDs indicators, one for the CO
and the other for the NO2sensor module; these LEDs
illuminate different colors to indicate normal (green),
warning (yellow), alarm (red) and error (blinking red)
conditions (see Table 5).
The concentrations of CO and NO2in the ambient air are
reported at the controller’s corresponding analog output:
the analog outputs range from 4 to 20mA during normal
operation (refer to Table 3 and Table 4).
Condition
Analog Output
[mA]
For 10 seconds after start-up
4
During sensor calibration
4
During sensor error
20
TABLE 6: Conditions when analog output is forced

Kele KCO-NO2 User’s Manual
Last Rev: 6/15/2020 Kele •3300 Brother Blvd. •Memphis, TN 38133 •WWW.KELE.COM Page 8 of 14
PRELIMINARY
Figure 7: Dip Switch Locations. CO specific
adjustments and connections are highlighted in
yellow while NO2specific adjustments and
connections are in green.
Dipswitch
Setting
Threshold Set Points
[ppm]
NO2
CO
Warn
Alarm
Warn
Alarm
0.7
2.0
15
30
1.0
3.0
25
40
2.0
4.0
30
45
2.5
4.5
35
45
Table 8: Alarm Threshold Setting
4.1 STARTUP
At startup, the controller has a 15 second warm-up period
before it begins normal behavior; during this time the
controller will:
Illuminate both the CO and NO2status LEDs
green
Output the minimum value of 4mA for both CO
and NO2. Analog outputs.
Deactivate both the Alarm and Warning relay
outputs.
4.2 SETTING WARNING AND ALARM THRESHOLDS
The controller has a warning and alarm threshold for each gas. These threshold values can be adjusted for each
sensor via dip switches on the controller’s main board (shown in Figure 7). Refer to details on setting the
thresholds for each sensor in Table 8.
NO2
CO
Federal OSHA Personal Exposure Limit (PEL).
5 ppm
50 ppm
TABLE 7: Federal OHSA exposure limits (29 CFR 1910.1051 TABLE Z-1)
4.3 WARNING AND ALARM CONDITIONS
The controller has two LEDs on the front panel (one for each gas.
These LEDs change color to indicate the controller’s current
operational status. Table 5 shows the behavior of the front
panel LEDs during normal operation. Two dry-contact SPDT
relays are provided on the controller, these relays activate
during warning and alarm conditions: refer to Section 3.3 for
location and wiring information.
4.4 SENSOR READINGS
Readings for the two sensors are independently reported on the
controller’s two 4 –20mA analog current loop outputs during
normal operation. Refer to Table 3 and Table 4 for the output
scaling for each sensor. Table 6 lists the operational conditions
that force the analog outputs to their limits regardless of
ambient gas concentrations.

Kele KCO-NO2 User’s Manual
Last Rev: 6/15/2020 Kele •3300 Brother Blvd. •Memphis, TN 38133 •WWW.KELE.COM Page 9 of 14
PRELIMINARY
FIGURE 8: Location of Calibration Controls. CO is green; NO2
is yellow.
5 SENSOR CALIBRATION
The KCO-NO2 must be calibrated at least every six months to maintain the specified accuracy.
Calibration entails individually exposing each of the sensors to two gases of precisely known concentrations (See
Table 9) so the measurement system can compensate for changes in the sensor’s sensitivity. Both sensors first use
the same zero gas cylinder for zero calibration, but then each sensor uses a different span gas cylinder for the span
calibration.
A ‘calibration cap’ is required to cover the sensor body and form an isolated pocket at the sensor that is filled with
the appropriate calibration gas supplied from cylinders of compressed gas through a regulator connected to it by
typically 1/4 “ OD gas tubing. Refer to the documentation for the
calibration kit you are using for instructions on how to assemble and
operate its gas supply components.
Each sensor must be sequentially calibrated with two different
gases. The Zero gas is the same for both sensors and is used for the
‘zero’ calibration, which must be done first. The ‘span’ gas is
different for each sensor and used for the ‘span’ calibration which
MUST be done ONLY AFTER a successful zero calibration. Each
calibration is started with one of the two calibration buttons (ZERO
and SPAN) for each sensor module as shown in Figure 8.
During calibration and for a period thereafter, the analog outputs are forced to 4 mA and the alarm relays are both
deactivated to avoid spurious alarm conditions from residual span calibration gas that has not yet dissipated from
the sensor.
5.1 CALIBRATION GASES
The table below shows the calibration gases required to calibrate the KCO-NO2.
Sensor
Calibration
Gas
Mixture (by volume)
Recommended
Accuracy
BOTH
Zero Gas
Air (≈ 20% O2, balance N2)Often
called “zero air” or “clean air”
CO
Span Gas
25.0 ppm CO, balance air
± 1.25 ppm
NO2
Span Gas
5.0 ppm NO2, balance air
TBD
TABLE 9: Gases required to calibrate KCO-NO2
A calibration kit that contains cylinders of the three required gases, a calibration cap, a regulator with associated
tubing and detailed instructions for calibrating the Model KCO-NO2 in a convenient carrying case is available from
Kele.

Kele KCO-NO2 User’s Manual
Last Rev: 6/15/2020 Kele •3300 Brother Blvd. •Memphis, TN 38133 •WWW.KELE.COM Page 10 of 14
PRELIMINARY
5.2 CALIBRATION PROCEDURE
The procedure shown in Table 9 MUST be done twice for each sensor. First it is done as a zero calibration using
the zero gas and only after a SUCCESSFUL zero calibration has been completed, the same procedure below is
done again as a span calibration using the span gas required for the sensor being calibrated as.
The progress and status of the calibration process is indicated by the color and flash-state of the front panel LED
for the sensor being calibrated. These LEDs are located at the edge of the main board adjacent to the ‘POWER’
connector. The CO sensor’s LED (LED1) is above the power connector; the NO2sensor’s LED (LED2) is below the
power connector.
For each calibration proceed as follows:
Apply the appropriate calibration gas to the sensor using a calibration cap, following the instructions for the
calibration kit being used. Start the desired calibration by pressing either the ‘ZERO’ or ’SPAN’ button of the sensor
being calibrated (see Figure 8) for 3 seconds. Gas sampling starts immediately, indicated by the sensor’s LED
blinking YELLOW.
Ensure that the calibration cap covers the sensor completely for the 2 minute sampling period. At the end of the
sampling period, the sensor’s status LED blinks GREEN if the calibration was successful or RED if not.
If successful (blinking GREEN):
the calibration completed successfully, but must be accepted by pressing the same button that started the
calibration again for 3 seconds while the LED is flashing GREEN. The LED then blinks GREEN/YELLOW for 2 minutes
indicating that the calibration was accepted. The cal gas flow can be shut-off as soon as the LED turns GREEN.
If not acknowledged within one minute the LED flashes RED/YELLOW indicating that the calibration was not
applied.
If NOT successful (blinking RED):
the calibration can be re-started while the LED is blinking RED by pressing the button that started the calibration
again for three seconds until the LED again blinks YELLOW. If no button is pressed during the 1 minute of blinking
RED, the LED switches to blinking RED/YELLOW for two minutes to indicate that the calibration was NOT applied.
If the span calibration for a sensor fails more than once, and the sensor has been in service for more than a year,
the most likely cause is that the sensor’s sensitivity has decreased by more than 20% from its original factory
calibration and must be replaced.
Calibrated sensor modules are available from Kele.
A successful calibration MUST be acknowledged within 1 minute of completion,
while the sensor’s status LED is still blinking green.
IF NOT ACKNOWLEDGED, THE CALIBRATION WILL NOT BE APPLIED.