PureAire Air Check O2 User manual

Air Check✓O2
Water Resistant O2Monitor
Instruction Manual
Part number 99118
PureAire Monitoring Systems, Inc.
1140 Ensell Road
Lake Zurich, Illinois 60047
Phone: [phone]
Fax: [phone]
Toll-Free: 888-788-8050
pureairemonitoring.com

Welcome to PureAire Monitoring Systems
I’d like to thank you for investing in our continuous life safety and process control toxic gas
monitoring systems.
PureAire offers an unbeatable combination of experience and innovation in solving the
safety and environmental needs of our customers. We are capable of providing small
systems of a few points to a total multi-point turnkey computerized package.
PureAire’s proprietary sensor cell technology and state-of-the-art electronics are designed
to interface with the latest distributive or PLC based control systems. We believe that our
experience, innovative products, and commitment to service will satisfy your specific
monitoring needs now and in the future.
Our growth is a result of our total commitment to supporting our customers. We are
available 24 hours a day, 7 days a week to help you when you need us. Our 24-hour
Emergency phone number is 1-847-420-3814. We can provide field service, preventative
maintenance programs and training to your technicians in the operation of our equipment.
Our goal is to provide the best after sale service and support in the industry. That is just
one way PureAire takes that extra step to ensure your complete satisfaction.
Thank you again for investing in PureAire Monitoring Systems for your monitoring needs
and I’m proud to welcome you to our family of valued and satisfied customers.
Sincerely,
Albert A. Carrino
President

Please Read Before Installation
The following will damage the Air Check Oxygen monitor.
1. The Air Check O2monitor requires 24 VDC regulated power.
Please Do Not connect the monitor to any voltage that exceeds
24 Volts DC, or ANY AC Voltage.
2. Do not power the Air Check Oxygen monitor with the oxygen sensor
unplugged from the main PC board. Do Not Connect the O2sensor to
the PC board while the monitor is powered. This Will Damage the O2
sensor.
3. The oxygen sensor cell is matched to the electronics. Never exchange
the electronics with an oxygen sensor from a different monitor.
4. When testing Sample Draw and Ex type monitors use an On Demand
regulator to expose the span gas to the monitor. (see section 6.1.2)
5. Only expose the monitor to span gas blends that consist of Oxygen
and Nitrogen only. Do Not expose the monitor to any combustible
gas, i.e. Methane, Hydrogen, etc. Exposure to combustible span gases
can damage the oxygen zirconium sensor cell.
6. Do not expose the Oxygen monitor to silicone, Freon or corrosive
compounds. They can cause a loss of sensitivity and damage the
sensor.
7. When using the Air Check O2Monitor in wash down areas make sure
you orient the filter with the drain opposite the water flow. (see section
3.2.4)
8. NOTE: If using longer lengths of sample tubing, the dust/water filter
must be located at the end of the sample line to work properly.
9. The Factory Password for entering the menus is 557

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Table of Contents
1: Introduction .....................................................................................................................2
1.1 Key Features........................................................................2
1.2 Component identification ....................................................3
2: Specifications...................................................................................................................7
2.1 Performance Specifications.................................................7
2.2 Gas Detection System..........................................................7
2.3 Signal Outputs .....................................................................7
2.4 Electrical Requirements.......................................................7
2.5 Physical Characteristics.......................................................7
2.6 System Default Factory Settings .........................................8
3: Installation.......................................................................................................................9
3.1 Site Requirements................................................................9
3.2 Mounting..............................................................................9
3.3 Wiring................................................................................13
3.4 Initial Startup.....................................................................13
4: Normal Operation..........................................................................................................15
4.1 Signal Outputs ...................................................................15
4.2 Instrument Faults...............................................................15
4.3 Routine Maintenance Schedule .........................................16
4.4 Loss of Power Indicator.....................................................16
4.5 Alarm Reset.......................................................................16
5: Air Check O2Monitor Programming ............................................................................18
5.1 Joystick Operation.............................................................18
5.2 Program Flowchart ............................................................19
5.3 Entering the Password .......................................................23
5.4 Changing the User Password.............................................24
5.5 Entering the Menus............................................................27
5.5.1 Set 4-20mA Loop .....................................................27
5.5.2 Set Formats...............................................................29
5.5.3 Set Alarm Threshold Polarity...................................31
5.5.4 Set Latching..............................................................33
5.5.5 Resetting a Latching Alarm......................................36
5.5.6 Set Alarm Delay .......................................................36
5.5.7 Set Zero Suppression................................................37
5.5.8 Set Alarm Thresholds...............................................37
5.5.9 Set Alarm Hysteresis ................................................39
5.5.10 Set Sensor Adjust....................................................40
5.5.11 Main Operation Mode.............................................41
6: Maintenance & Cell Verification ..................................................................................42
6.1 Sensor Verification............................................................42
6.2 Sensor Verification Procedure...........................................43
7: Appendix .......................................................................................................................46
Rev. 4.08 January 2021

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1: Introduction
The Air Check ✓O2water resistant monitor is a self-contained Oxygen deficiency detection system
suitable for remote sampling of confined spaces that require daily wash-downs. It’s a compact gas
monitoring system that’s ideal for the continuous monitoring of inert gas storage areas, confined
spaces, and other locations where low oxygen levels may pose a hazard to personnel. Unlike
electrochemical sensor cells the Air Check ✓O2zirconium cell provides stable oxygen readings even
in areas where temperature and humidity levels are changing. The PureAire Air Check ✓O2
Deficiency Monitor is suitable for either indoor or outdoor use. Factory calibrated against a NIST
traceable reference standard and UL, CUL and Ce approved.
The heart of the monitoring system is a long-lasting zirconium sensor, which responds to low oxygen
conditions within seconds and provides accurate measurements over a wide temperature and humidity
range. The zirconium O2sensor cell will operate continuously for 8 or more years and requires an
absolute minimum of maintenance. There are no zero or span calibration pots to adjust and when
compared to disposable type sensors, our long-life zirconium O2sensor can save up to hundreds of
dollars in annual maintenance.
Ideal for continuously monitoring oxygen levels in food processing areas where inert gases are used in
freezing tunnels, the Air Check ✓water resistant O2 monitor does not drift or loose sensitivity when
the weather or temperature changes. The electronics are housed in a 4X IP65 water resistant housing
capable of withstanding water projected from a nozzle.
Each system consists of a long-life zirconium oxide sensor cell and three-wire transmitter. The Air
Check ✓O2monitor may be used as a stand-alone gas detector, linked to optional PureAire single and
multipoint controllers, or connected to your own centralized control and surveillance system. This
manual covers the installation, operation, and maintenance of the Air Check ✓water resistant O2
deficiency monitor.
1.1 Key Features
The Air Check ✓O2monitor incorporates several user-friendly features designed to simplify
installation, operation, and maintenance.
1.1.1 Long Life Zirconium Oxide O2Sensor
The system’s O2sensor cell has a life of well over 8 years of continuous operation. Unlike
concentration O2cells, PureAire’s exclusive zirconium oxide sensor cell does not need an oxygen
reference gas for proper operation. The Air Check ✓O2monitor can detect low oxygen levels in
confined spaces and process tools without the need of a reference gas.
1.1.2 Smart Electronics
The Air Check ✓O2monitor incorporates a special electronic circuit that continuously monitors sensor
operation. With the built-in alarm relay, any cell degradation or complete failure will immediately be
detected. This smart circuitry alerts the user to sensor faults and other electrical problems that may
interrupt surveillance through the standard mA signal output signal and through the fault relay.

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1.1.3 Calibration
The Air Check ✓O2monitor incorporates a stable zirconium oxide sensor that rarely requires
adjustment. Changing barometric pressure changes or changes in temperature and humidity do
not affect the zirconium oxide oxygen cell. The earth is a wonderful source of calibrated
oxygen at 20.9%, therefore under ambient conditions, visual verification of the Air Check ✓O2
monitor to 20.9% oxygen is easily performed. There are no zero or span pots to adjust. The O2
monitor only requires periodic testing with nitrogen to verify the cells response to low oxygen
levels. See Section 6.2 for the testing procedure to nitrogen.
1.2 Component Identification
1.2.1 Front View Exterior
1. Front Cover —This is a removable, waterproof cover that protects the
interior of the transmitter. It fastens through 4ea. captive screws
2. Joystick —Used for selecting and adjusting the built-in menus. The Air
Check ✓O2Sample draw monitor has dual level user selectable alarms.
3. Digital Display —This displays the Oxygen levels in percentage. The
normal oxygen level on earth is 20.9%
4. Front Cover Fasteners—The Air Check ✓O2Sample draw monitor has
4ea. captive screws to remove the front window from the base unit.
5. Sample Inlet —This inlet permits the flow of oxygen to enter the sensor
cell.
Front Cover
Alarm and Fault
Relays
Mounting Feet
(4ea.) not shown)
Sample Inlet
Digital Display
Joystick
Front panel
fastening
screws (2 ea.)
Front Cover
Fasteners
(4ea.)
Sample
Exhaust
Cable Strain
Relief

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6. Sample Exhaust —This permits the flow of oxygen to exit the enclosure.
7. Cable strain relief —This is the sealed opening in the transmitter housing
for connecting the input power, 4-20 mA output and relay wiring.
1.2.2 Front View with front cover removed
8. Sample Pump —Used to bring in a sample to the oxygen cell. Flow rate is
preset at the factory. Flow rate is continuously protected with a built-in flow
sensor. See Section 4.2; Instrument Faults
9. Oxygen Sensor Assembly —A zirconium oxide sensor, which detects and
measures the level of oxygen. When exposed to oxygen, the sensor outputs
an electrical signal proportional to the actual concentration of oxygen.
10. Front Panel Retaining Screws —These captive screws are used to mount
the display front panel and O2electronics to the enclosure.
NOTE: When unfastening the front panel electronics, apply upwards
pressure on the back of the front panel to release the captive screws.
11. Alarm Indicators —3 multi colored LED indicators for showing:
Alarm level 1 Orange LED
Alarm level 2 Red LED
Fault Alarm Yellow LED
Sample
pump
Joystick
Oxygen
sensor
assembly
Retaining
Screws for
electronics
panel
Alarm Relay
LED’s
Fault
Alarm 1
Alarm 2

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O2water resistant monitor front cover removed
1.2.3 Transmitter Interior
Alarm and Fault
Relays &
Terminal blocks
Relays
Flow Sensor
O2Sensor
connector
Sample pump
connector
Sample Pump
1. Power
Analog output
Terminal Block
Common
Common
mA output
+ 24 VDC
+ 24 VDC
3. PTC
Resettable
Fuse
2. Sensor cell
connector

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1. Power Analog Terminal Block —This terminal block is where the 24VDC
power and 4-20 mA analog output connection is made.
2. Sensor Cell Connector —This connector is where the Oxygen sensor cell
is connected. NOTE: Never connect the oxygen sensor to this connector
while the monitor is powered. This will damage the oxygen sensor
3. PTC Resettable Fuse —The PCB is protected with a PTC Fuse that is
resettable and Never needs to be replaced. If it trips, you will need to turn
power off to the monitor. When power resumes the fuse will reset.
1.2.4 Alarm Relay Board
(Identification legend is located between the relay and connector)
Relay 2 Relay 1 Fault Relay Remote
NC C NO NC C NO NC C NO Reset
Flow Sensor
Pump
Connector
Sensor cell
Connector

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2: Specifications
NOTE: For our continual product improvement, all specifications are subject to change without notice.
2.1 Performance Specifications
Sensor Type: Long Life Zirconium Oxide Sensor Cell 0-25%
Response Time: Within 2 seconds of any change in O2.
Repeatability: ± 2% of reading
Fault Indicators: Loss of VDC power (analog signal drops to 0 mA).
Sensor cell failure: Fault relay activated
Operating Temp: -40° to 104°F (-40° to +40°C); consult PureAire for lower or higher temperature
Humidity: 0 to 100% RH; IP65 water resistant enclosure
Environment: Altitude 2000 m, PSU only UL spec. Pollution Degree 3
Sampling distance: Max distance 100 feet, (33M)
UL / CUL listing: Measuring Equipment E363306
Ce EN 61000-3-2:2006 EMC, EN 61000-3-3:2008 EMC, EN61010-1-3-2013 LVD
2.2 Gas Detection System
Type: Long Life Zirconium Oxide Sensor Cell, Range 0-25%
Sensor Life: 8-10 years under normal conditions.
Transmitter: Microprocessor electronics with built-in 3-digit backlit LCD display
Joystick operated menus
2.3 Signal Outputs
Local Display: Digital display calibrated for Oxygen. The range is stated on the model label
and also can be accessed via the joystick on the front panel. In the measurement
mode pushing the joystick down will scroll the gas and range on the display.
Push the joystick down again to stop the scrolling and display the gas again.
Analog Output: DC 4-20 mA
Relay Output: Dual level user selectable alarm relays and one fault relay
Rated, 2amps @ 24VAC or 24VDC
2.4 Electrical Requirements
Power: 24 VDC external power. A regulated 24VDC power supply is required.
Consumption: Approximately 300mA
2.5 Physical Characteristics
Dimensions: 7.0 (W) x 5.0 (H) x 5.0(D) inches; 178 x 127 x 127 mm
Weight: 4.0 pounds (2 kg)
Enclosure Type: Polycarbonate wall mount IP65 water resistant. Not intended for explosive
atmospheres or electrically classified areas.

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2.6 AirCheck O2System Default Factory settings
The Air Check ✓O2water resistant monitor is shipped with factory defaults for the alarm relay
settings. The following are the factory defaults:
Menu Function
Factory Default
Menu Defined
Set 4-20mA loop
The mA output is set at
the factory using a
calibrated Fluke meter.
Use this function to adjust the
Oxygen monitors 4mA, (Zero) and
20mA, (Span) to your PLC or
distributive control system.
Set Formats
LED and alarm relay
State **
Alarm 1 = Normal
Alarm 2 = Normal
Fault = Normal
Do you want the relays to
energize, (normal) or de-energize,
(fail safe) when the alarm
activates?
Set Alarm Threshold
Polarity
Alarm 1 = Inverted
Alarm 2 = Inverted
Audio = Inverted*
Do you want to alarm at a level
higher, (normal) or lower,
(inverted) than the alarm
threshold?
Set Latching
Alarm 1 = Non-latching
Alarm 2 = Non-latching
Audio = Non-latching
Do you want the alarm to
automatically reset? (non-latching)
or do you want to manually reset
the alarm? (latching)
Alarm Delay
Alarm = 5 seconds
How long do you want to wait
until the relay alarms activate?
Zero Suppression
000 = 0.00%
This function is Not Enabled on
the Oxygen monitor.
Set Alarm
Thresholds
Alarm 1 = 19.5 %
Alarm 2 = 18.0 %
Audio = 19.5%*
At what level do you want to
alarm?
Set Alarm Hysteresis
Alarm 1 = 0.0 %
Alarm 2 = 0.0 %
Audio = 0.0 %
For use when using the O2monitor
for control or valves and process.
See Section 5.5.9
Sensor Adjustment
No factory default
For use when dynamically gas
calibrating the Oxygen monitor to
a known span gas.
See Section 6.2
Manage Passwords
Factory default is 557
For use when changing the
password from factory default to a
new password of your choice.
NOTE:The built-in relay settings may be changed by the user in the field. Refer to
Section 5.4.2
* NOTE: The Audio alarm feature is optional.
** NOTE: The LED indicators on the front panel are connected directly to the alarm
relays.

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3: Installation
3.1 Site Requirements
The Air Check ✓O2monitor enclosure should be mounted in an area free of vibration and electrical
noise or interference. If possible, avoid areas with high temperatures.
WARNING: The Air Check ✓ O2monitor is not designed for installation in
hazardous areas. Consult PureAire for information on enclosures for use in
hazardous environments.
3.2 Mounting
3.2.1 Transmitter Enclosure
The Air Check ✓O2monitor is designed primarily for wall mounting and should be installed at a
height convenient for operation, maintenance, and viewing of the instrument display.
3.2.2 Air Check ✓O2monitor
The transmitter and sensor should be installed in a location where gas leaks are likely to occur or
where released gases may accumulate. It should be mounted no closer than 12 inches above floor level.
Airflow within the monitored area, the characteristics of the gas (lighter or heavier than air), and the
position of workstations and personnel should all be considered in determining the most suitable
installation location.
NOTE:Leave clearance room on the bottom of the Oxygen monitor for the inlet dust/water filter,
which adds an additional 12 inches.
7.0”
12”(approx.)

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3.2.3 Enclosure Mounting Feet
Mounting Feet
Can be oriented in
any direction
Feet can also be
removed for
mounting the O2
monitor flush with
a wall or other
surface

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3.2.4 Air Check ✓Sample Inlet Filter
To protect the pump from dust and water, the use of a special filter is supplied. On installation, attach
the particulate/water filter to the sample inlet by pushing the filter into the ¼” tube compression fitting.
Aligning the arrow, (printed on the filter) towards the monitor. The filter pulls air from both vertical
and horizontal tubes. Never connect any sampling tubing to either tubing ports. When sampling
remote, ALWAYS locate this filter at the end of the sample line.
The Air Check ✓O2Sample Draw monitor has an internal sample flow rate that is programmed at the
factory and cannot be changed in the field. A flow sensor on the relay board continually monitors flow
rate for1/2”OD x 3/16”ID tubing up to 100 feet. When a loss of flow is detected, a signal is sent to
the fault relay and the front mounted LED will activate. Sample flow to the monitor is continuously
monitored and controlled by the flow control microprocessor.
NOTE: If using longer lengths of sample tubing, the dust/water filter must be located
at the end of the sample line to work properly.
NOTE: If the sample line is blocked, the fault indicator will illuminate, and the pump will
accelerate to try and reestablish the proper flow rate. If the line is cleared, the pump
will speed and slow down and the fault light will turn off when the flow rate is back to
factory setting. The “Flow Fault”message can be cleared by pushing the joystick down
Depending on the environment, replacement of this filter should be performed every 12 months. In
dusty environments, filter replacement may need to be replaced more frequently. If the filter becomes
completely blocked, the internal flow sensor will detect the loss of flow and activate the fault relay and
LED. Order filter part number 90179
NOTE: NEVER connect
any tubing to either the
inlet or drain port of the
filter.
Sample air can enter from
either port. This is the
reason why the water
filter must be located at
the end of the sample
line.

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¼” tube push to
connect fitting **
Dust/Water Sample
filter p/n 90179
**NOTE: PureAire recommends
the use of polypropylene sample
tubing with the dimensions of
1/4” OD by 3/16” ID. The total
length of tubing should not
exceed 100 feet.
NOTE: When used in wash
down areas, the dust/water
filter drain must be oriented
opposite the water flow.
(i.e, orient the drain towards
the back of the monitor to
prevent water from building up
inside the drain.)
NOTE: NEVER connect
any tubing to either the
inlet or drain port of the
filter.
Sample air can enter from
either port. This is the
reason why the water filter
must be located at the end
of the sample line.
Photo shown is a
waterproof monitor
located at the risk
site.
If any length of
sample tube is
needed to sample
remote, the water
filter must be located
at the end of the
sample tubing.

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3.3 Wiring The Air Check ✓O2monitor requires a single, 3-wire shielded cable for analog output
and 24 VDC power input. A three-wire shielded cable; 3-conductor, 18 AWG stranded
General Cable E2203S.30.860, or equivalent is recommended for the connection. The
analog out and VDC power in connections are made on the terminal block inside the
transmitter housing.
These connections are made as follows:
* Caution: DO NOT connect to a powered current loop receiver. The Air Check
Oxygen monitor supplies the current loop power.
3.3 Initial Startup
Once installation of the gas detector has been completed, it is ready for startup. The following
procedures should be performed before putting the instrument into operation:
1. Check the integrity of all wiring.
2. Apply 24 VDC power to the Power Supply PCB board. The sample pump
will activate. Also, the digital display second line will quickly display the
DTM, (digital transmitter module) serial number and Software version.
NOTE: To display the DTM numbers push the joystick to the left. To display the gas and range
push the joystick down and the gas and range will continuously scroll. To stop the
scrolling, push the joystick down.
The instrument should now be powered up. Upon power up, the Air Check ✓O2monitor LCD
displays the PureAire logo and then starts a 4-minute, (240 second) count down as the current to the
zirconium oxide O2sensor stabilizes. The monitor will output a 4 mA signal during the entire warm-
up period. After the countdown, the oxygen sensor will continue to reach its operating temperature for
3.4
-Common
-Common
mA* 4-20mA signal
output to PLC
+24VDC Power
+24VDC Power
Identification Legend
PureAire provides
the plug-in power
supply

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approximately 30 minutes and the reading displayed will slowly increase to ambient. Do not make
any adjustments to the reading until after the monitor has been powered for at least an hour.
NOTE: Immediately after the countdown, the monitor will display
“FLOW FAILURE: OUT OF RANGE”on the top line and disappear. This is
a fault history message only and is generated on start-up to verify the integrity of
the system. The message will automatically clear and “Oxygen” will display
on the top line and the “20.9%” reading will display on the bottom line.
If the fault is still present, the actual fault code will display on the bottom line.
The instrument should now be operating properly and is ready for monitoring.
NOTE: The Air Check ✓O2monitor’s reading may be adjusted to the ambient oxygen level.
See section 6.1 for instructions on adjusting.
Pump Adjustment
The Air Check Sample Draw O2monitor has a built in digitally controlled flow
controlled sample pump. The pump flow is set at the factory and should not
require adjustment. It has a range to accommodate tubing lengths of 3 feet to
over 100 feet. If flow adjustment is necessary, please contact PureAire.
NOTE: Normal flow rate is 0.25 liters per minute. (250cc/min)
Oxygen
239 WARM
13

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4: Normal Operation
The Air Check O2monitor is a single point monitor designed for the continuous detection and
measurement of ambient oxygen concentration levels.
4.1 Signal Outputs
The Air Check ✓O2monitor outputs a continuous 4-20 mA analog signal proportional to the
measured concentration of oxygen. 4 mA represents 0% O2and 20 mA represents 25% O2which is the
full range. In the event of a system fault, a specific factory defined code will be displayed on the local
digital display. This code will indicate the exact nature of the system fault. A few codes are listed
below.
CAUTION: DO NOT connect to a powered current loop receiver. The Air Check
Oxygen monitor supplies the current loop power.
4.2 Instrument Faults
The Air Check ✓O2monitor incorporates a number of self-checking features to
ensure reliable operation. In the event that a fault condition is detected, the
analog output signal is altered: A few common error codes are displayed in the
following table:
Condition
Analog Signal
**Supply Voltage Out of
Range Fault code 16
Analog output drops to 2 mA
Transmitter cable cut
Analog output drops to 0 mA
O2Cell current fault
Fault Code 128
Analog output drops to 2 mA
Fault Relay activates
O2 System Warm Up
Analog output drops to 2 mA
Fault Relay activates and turns off when system is
in the Oxygen operation mode
O2Cell voltage fault
Fault Code 64
Analog output drops to 2 mA
Fault Relay activates
No Flow to the Oxygen
sensor
Fault Code 32
Analog output drops to 2 mA
Fault Relay activates
EEPROM Fault 08
Analog output drops to 2mA
NOTE:All system faults are displayed on the front panel. Each fault has
it’own specific code to identify the specific problem. Please contact PureAire
whenever a fault is displayed.
** When using your own power supply please ensure that the voltage is
regulated to 24VDC +/- 0.5 volts. If the voltage is too low or high you will
activate a “Supply Voltage Out of Range fault and disable the monitor.

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NOTE: If a Fault condition clears itself, (Yellow LED is no longer illuminated)
The Fault message will continue to scroll until manually cleared.
To clear the fault message, push the joystick down (- Minus)
4.3 Routine Maintenance Schedule
Continuous gas detection systems depended upon to measure and detect hazardous gas leaks in the
workplace requires periodic maintenance to ensure proper operation. The frequency with which this
routine maintenance is required depends on the environment. The following table is intended to serve
as a general guideline for routine maintenance. The conditions in your particular application, as well as
your organization’s maintenance policies, will ultimately determine the best routine maintenance
schedule for your equipment. Routine Visual Checks
Items to check
Check for power and proper operation
Condition / status when
operating properly
Unit should be outputting a 17.34 mA signal when
the oxygen level is at 20.9%. The LCD digital
display should also indicate 20.9% 02when the
oxygen is at ambient levels.
4.3.2 Recommended Routine Maintenance Schedule
Routine Visual Checks Every 6 - 12 months
Sensor Verification with nitrogen Every 6 - 12 months**
** The ambient oxygen level is 20.9%; therefore, under ambient conditions visual verification of the
Air Check ✓O2monitor to 20.9% oxygen is easily performed. The O2monitor only requires periodic
testing with nitrogen to verify the cells response to low oxygen levels. See Section 5.5.10 for how to
make minor adjustments.
4.4 Loss of Power Indicator
In the event the Air Check ✓O2monitor loses 24VDC power, the 4-20 mA analog output signal drops
to 0mA. The LCD display will also display a blank screen.
4.5 Alarm Reset
It the Air Check ✓O2monitor is supplied with the optional alarm relays, whenever the monitors alarms
are activated, the built-in alarm relays, panel mounted LED’s and optional audio horn will also
activate. When the relay settings are non-latching, the alarm relays, LED’s and horn will automatically
reset. If the relay settings are latching, then a manual reset of the alarms are required. Resetting the
alarms can be performed through use of the joystick or using the remote reset function.

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Joystick –You must enter the password to enter the reset function. After the password is entered and
accepted, push the joystick in; (enter) to reset the alarms.
Remote Reset –Refer to section 1.2.4. for location on PC board. The alarm relay board has a two-pin
connector for wiring to a remote switch. When connected to a switch, this remote reset will bypass the
joystick and a password will not be needed to reset the alarms.
NOTE:The oxygen levels must recover above the alarm thresholds before the horn can be
reset from the remote reset switch or joystick.