Kele KCO-NO2 User manual

PRELIMINARY
KCO-NO2 Sensor
User’s Manual
90-0201-01

KCO-NO2 User’s Manual
90-0201-01 Kele •3300 Brother Blvd. •Memphis, TN 38133 Page: 2
WWW.KELE.COM
Revision History
Revision
Date
Changes
90-0201-00
3/18/21
Original Issue
90-0201-01
4/12/21
Change CO sensor ToS to 200 ppm from 100 ppm.

KCO-NO2 User’s Manual
90-0201-01 Kele •3300 Brother Blvd. •Memphis, TN 38133 Page: 3
WWW.KELE.COM
Contents
Revision History ..................................................................................................................................2
1Specifications................................................................................................................................4
2Mechanical Installation.................................................................................................................5
2.1 Enclosure Dimensions................................................................................................................5
3Electrical Installation.....................................................................................................................6
3.1 Analog Reporting-Output Connections.....................................................................................6
3.2 Relay Connections.....................................................................................................................6
3.3 Power Connection......................................................................................................................7
4Operational Description ................................................................................................................8
4.1 Normal operation........................................................................................................................8
4.2 Startup........................................................................................................................................9
4.3 Setting Warning and Alarm Threshold....................................................................................10
4.4 Warning and Alarm Conditions...............................................................................................10
4.5 Abnormal operation..................................................................................................................10
5Sensor Calibration.......................................................................................................................11
5.1 Calibration Gases.....................................................................................................................11
5.2 Calibration Procedure..............................................................................................................13
6Sensor Module Replacement.......................................................................................................14
6.1 Sensor Errors ...........................................................................................................................14
6.2 Replacement Sensors:..............................................................................................................14
6.3 Field Replacement of Sensor Modules....................................................................................14
7Warranty......................................................................................................................................15
7.1 Duration...................................................................................................................................15
7.2 Limited Warranty and Remedies.............................................................................................15
8Disclaimers..................................................................................................................................16
8.1 Inspection and Maintenance....................................................................................................16
8.2 Life Safety ...............................................................................................................................16

KCO-NO2 User’s Manual
90-0201-01 Kele •3300 Brother Blvd. •Memphis, TN 38133 Page: 4
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1 Specifications
Mechanical
Chassis Construction
Robust 18 Ga. Grey powder-coated steel. Hinged & Pad-lockable, or
screw-on cover style available.
Weight
2.0 Lbs.
Operating Temperature
-20 to 50°C (-4 to 122°F)
Operating Humidity
15 –90 %RH
Storage Temperature
0 to 20°C (32 to 68°F) 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 Vents
Natural Ventilation through 18 0.1” diameter (2.54 mm) vents.
Recommended calibration cap diameter
20.5 mm (.807”)
External Indicators
Separate tri-color LEDs indicates operational status of each senor.
Knockouts
4 trade ½” knockouts (1 per side)
Electrical
Operating Power Voltage
14 to 30 VAC (RMS) or 15 to 45 VDC
polarity independent, isolated power supply
Power Consumption
< 5W
Control Relays
Two separate SPDT relays for warning and alarm outputs.
UL rated: 10 Amps max at 277 VAC (RMS) or 30 VDC.
Concentration Reporting Outputs
Two powered 4–20 mA current loop outputs (one for each sensor).
4 mA output => 0 ppm, •20 mA => full scale output.
Maximum loop resistance: 510Ω
Termination
Pluggable screw-terminals for use with 12 AWG or thinner wire.
Stranded wire recommend for 18 AWG or heavier wire.
Carbon Monoxide Sensor (CO)
Sensor Type
Electrochemical
Measurement Range
0 –200 ppm
Analog Output Range
4mA to 20mA (corresponds to 0 to 200 ppm)
Accuracy
±5% of Full Scale (typical)
Calibration Interval
6 Months; factory calibrated when new
Sensor Life
2 Year typical
Calibrated Field-Replaceable Sensor
KMOD-CO
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
± 0.75 ppm (typical)
Calibration Interval
6 Months; factory calibrated when new
Sensor Life
2 Year typical
Calibrated Field-Replaceable Sensor
KMOD-NO2

KCO-NO2 User’s Manual
90-0201-01 Kele •3300 Brother Blvd. •Memphis, TN 38133 Page: 5
WWW.KELE.COM
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 2 and the screw-down
cover version is shown in Figure 1. 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.
May be mounted in any orientation but hinge on the left side is most common.
Mounting holes are made for direct wall screws for the surface encountered. (Mounting screws
not provided) or switch box spacing.
2.1 Enclosure Dimensions
Distance from center
Case Style
Mtg hole diameter
Horizontal
Vertical
Hinged
5/16” (7.94 mm)
1.25” (31.75 mm)
1.50” (38.10 mm)
Screw-down
9/32” (7.14 mm)
1.50” (38.10 mm)
1.50” (38.10 mm)
TABLE 1: Mounting Hole Diameters & Locations
Figure 2: KCO-NO2 Hinged Front Panel Enclosure
Figure 1: KCONO2 Screw Front Panel Enclosure
Dimensions

KCO-NO2 User’s Manual
90-0201-01 Kele •3300 Brother Blvd. •Memphis, TN 38133 Page: 6
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3 Electrical Installation
The controller is not equipped with a power switch; it is operational whenever sufficient power is
applied to the low voltage power input terminals (do not connect to line).
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 2 and Figure 1 for details and dimensions of the enclosures.
3.1Analog Reporting-Output Connections
Each sensor’s readings are individually reported by 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 3 and the NO2output is provided at the
terminals highlighted yellow in Figure 3. 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
(See Figure 6).
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.
3.2 Relay Connections
The controller has two SPDT dry-contact relay output terminals (shown in Figure 4). The relays are
UL rated at 10 Amps at up 277 VAC, and the associated circuitry meets UL criteria for connection
to line voltage below 300 volts. Some jurisdictions may require such heavy gauge wires that the
full capabilities of the relays are not operationally
achievable.
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.
Figure 4: Relay Outputs
FIGURE 3: Location of Analog Output
Terminals.

KCO-NO2 User’s Manual
90-0201-01 Kele •3300 Brother Blvd. •Memphis, TN 38133 Page: 7
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FIGURE 5: Example wiring Diagram for
Normally Open Operation.
FIGURE 6: Location of Power Connector
An example wiring diagram for relay connections is provided in Figure 5. 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 4).
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.
3.3 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 6). Power to the
controller can be either AC or DC voltage; DC voltage can
be connected in either polarity.
The input power is electrically isolated from the analog
outputs.
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.

KCO-NO2 User’s Manual
90-0201-01 Kele •3300 Brother Blvd. •Memphis, TN 38133 Page: 8
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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 3: Front panel status LED Indications.
Sensor
Concentration
at 4 mA
Concentration
at 20 mA
CO
0 ppm
200 ppm
NO2
0 ppm
10 ppm
Table 4: Sensor Analog Output Scaling
4 Operational Description
4.1 Normal operation
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 or
a minor alarm annunciator 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).
Mode
Front Cover
LED
Analog
Output
Relays Actuated
Comment
Normal
Steady Green,
Yellow or Red
4 –20 mA
Depends on
concentration
During normal operation
Standby
Various
4 mA
NONE
During start-up interval or any
time during calibration
Sensor
Error
Slow Blinking
Red
20 mA
Warning/
Ventilation
After calibration of expired
sensor or detection of sensor
failure.
Sensor is no longer operational
and must be replaced.
TABLE 2:Operational State Summary

KCO-NO2 User’s Manual
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The controller has four factory-preset, pairs of warning and alarm levels for each gas (see Figure 8).
Each setting determines both the sensor’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 CO or NO2concentration rises above its alarm threshold, the controller’s ALARM
relay is also 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 cover 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 3).
The concentrations of CO and NO2in the ambient air are reported at each senor’s analog output.
The analog outputs range from 4 to 20mA during normal operation (see Table 4).
4.2 Startup
At startup, the controller has a short (less than 1 minute) warm-up period before it begins normal
operation; 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.

KCO-NO2 User’s Manual
90-0201-01 Kele •3300 Brother Blvd. •Memphis, TN 38133 Page: 10
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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
2.0
30
45
2.5
4.5
35
45
FIGURE 8: Setting Warn & Alarm Set points
Figure 7: Dip Switch Locations. CO specific
adjustments and connections are highlighted
in yellow while NO2specific adjustments
and connections are in green.
4.3 Setting Warning and Alarm Threshold
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
Figure 8.

NO2
CO
Federal OSHA Personal
Exposure Limit (PEL).
5 ppm
50 ppm
TABLE 5: Federal OHSA exposure limits
(29 CFR 1910.1051 TABLE Z-1)
4.4 Warning and Alarm Conditions
The controller has two LEDs on the front panel (one for
each sensor). These LEDs change color to indicate the
controller’s current operational status. Table 3 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.
Readings for the two sensors are independently reported
on the controller’s two 4 –20mA powered current loop
outputs during normal operation. Theses outputs are
electrically isolated from the operating power
connection.
Table 2 lists the operational conditions that force the
analog outputs to their limits regardless of ambient gas
concentrations.
4.5 Abnormal operation
Both of these conditions will put the KCO-NO2 into
‘Sensor Error’ mode (see Table 2).
Sensor Expired
Happens only after a span calibration if the sensitivity of the sensor has decreased by more
than the manufacturers specification (usually 20%)
Sensor Failure:
Can happen at any time. Caused when the sensor supervision circuitry detects a catastrophic
loss of a senor’s sensitivity, usually caused by a depletion of the senor’s electrolyte through a
leak or evaporation.