PureAire Air Check Lite User manual

Air CheckLite
Toxic Gas Monitor
Instruction Manual
PureAire Monitoring Systems, Inc.
1140 Ensell Road
Lake Zurich, Illinois 60047
Phone: [phone]
Fax: [phone]
Toll-Free: 888-788-8050
www.pureairemonitoring.com
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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’re 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 digital 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’re 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’s 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
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Table of Contents
1: Introduction......................................................................................................................2
1.1 Key Features ........................................................................2
1.2 Component identification.....................................................3
2: Specifications...................................................................................................................6
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.......................................................8
3: Installation .......................................................................................................................9
3.1 Site Requirements................................................................9
3.2 Mounting..............................................................................9
3.3 Sensor Installation..............................................................10
3.4 Wiring................................................................................11
3.5 Initial Startup .....................................................................11
4: Normal Operation..........................................................................................................12
4.1 Signal Outputs....................................................................12
4.2 Instrument Faults ...............................................................12
4.3 Routine Maintenance Schedule..........................................12
4.4 Loss of Power Indicator.....................................................13
5: Maintenance & Calibration............................................................................................14
5.1 Sensor Cell Removal and Installation................................14
5.2 Electrolyte Replacement....................................................15
5.3 Sensor Calibration..............................................................19
6: Drawings........................................................................................................................24
7: Appendix........................................................................................................................29
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1: Introduction
The Air Check Lite Toxic Gas Monitoring System is a self-contained gas detection system
suitable for keeping a wide range hazardous gases under continual surveillance. Each system
consists of an amperometric, electrochemical sensor cell and two-wire transmitter. The Air
Check Lite Monitoring System may be used as a stand-alone gas detector, linked to an
optional controller (RX-1G), or connected to your own centralized control and surveillance
system.
This manual covers the installation, operation, and maintenance of the
Air Check Lite Monitoring System for the following gases:
Ammonia (NH3) 0 to 75 ppm
Arsine (AsH3) 0 to 1 ppm
Boron Trichloride (BCl3) 0 to 9 ppm
Carbon Monoxide (CO) 0 to 100 ppm
Chlorine (Cl2) 0 to 3 ppm
Diborane (B2H6) 0 to 1 ppm
Fluorine (F2) 0 to 1 ppm
Hydrogen (H2) 0 to 4% vol
Hydrogen Bromide (HBr) 0 to 9 ppm
Hydrogen Chloride (HCl) 0 to 15 ppm
Hydrogen Fluoride (HF) 0 to 9 ppm
Hydrogen Sulfide (H2S) 0 to 30 ppm
Nitric Oxide (NO) 0 to 100 ppm
Nitrogen Dioxide (NO2) 0 to 9 ppm
Oxygen Deficiency (O2) 0 to 25%
Phosphine (PH3) 0 to 1 ppm
Silane (SiH4) 0 to 15 ppm
1.1 Key Features
The Air Check Lite Monitoring System incorporates a number of user-friendly features
designed to simplify installation, operation, and maintenance.
1.1.1 Plug-in Sensor
The system’s renewable, electrochemical sensor features a special plug-in design to simplify
sensor installation and removal.
1.1.2 Smart Electronics
The sensor cell also incorporates a special electronic circuit which permits “ex-situ” calibration.
This smart circuitry also alerts the user to low electrolyte, sensor faults, and other problems
which may interrupt surveillance.
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1.2 Component Identification
1.2.1 Front View Exterior
1. 4-20 mA Signal Output Terminal —This connection serves as both
the
4-20 mA output connection and 24 VDC power input connection. See
section 3: Installation for more information.
2. Sensor Cable and Connector —Allows remote mounting of sensor.
Sensor plugs into receptacle on end of sensor cable.
3. Sensor Cover —This cover protects the gas sensor. It threads onto
the upper portion of the sensor.
4. Gas Sensor —An amperometric, electrochemical sensor which
detects and measures the target gas. Different gas sensors are required
to detect different gases. When exposed to the target gas, the sensor
outputs an electrical signal proportional to the gas concentration.
5. Cable Port —This is the opening in the transmitter housing for
connecting the 4-20 mA output and 24 VDC power cable.
6. Transmitter Cover —A removable cover that protects the interior of
the transmitter.
7. Transmitter Cover Fasteners —These captive screws secure the
transmitter cover in place.
1.
2.
6.
3. & 4.
5.
7.
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1.2.2 Transmitter Interior
1. Calibration Port —This port is used for when calibrating Air Check
Lite Monitoring Systems which do not have a digital display. See
Sensor Calibration elsewhere in this manual.
2. Terminal Block —This terminal block is where the VDC
power/analog output connection is made.
3. Sensor Cell Terminal Block —This terminal block is where the
sensor cell cable output connection is made.
1.2.3 Electrochemical Sensor
1. Span Potentiometer —This potentiometer is used to adjust the
sensitivity of the sensor cell. It should only be adjusted when
calibrating the instrument.
2. Zero Potentiometer —This potentiometer is used to adjust the
instrument’s
4 mA analog output signal to ensure that it is transmitting a 4 mA
signal when the instrument is reading a zero concentration.
3. Shorting Plug —The sensor is shipped with a jumper (shorting plug)
in place. This plug should be removed prior to sensor installation and
replaced whenever the sensor is removed for extended periods of time
(storage, etc.).
1. Span Potentiometer
2. Zero Potentiometer
3. Shorting Plug
1. Calibration Port
2. Terminal Block
3. Sensor cell
Terminal Block
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4. Sensor Connector —Female connector; plugs into receptacle on
sensor cable.
5. Threads for Sensor Cover —Secure sensor cover onto sensor body.
4. Sensor Connector
5. Threads for Sensor
Cover
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6. Sensor Cable and Connector —Allows remote mounting of sensor.
Sensor plugs into receptacle on end of sensor cable.
7. Sensor Cover —This cover protects the gas sensor. It threads onto
the upper portion of the sensor body.
6. Sensor Cable and
Connector
7. Sensor Cover
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2: Specifications
NOTE: Due to our commitment to continual product improvement, all
specifications are subject to change without notice.
2.1 Performance Specifications
Sensor Type: Plug-in diffusion type electrochemical cell.
Response Time: Within 30 seconds to T90.
Repeatability: ±10% of full scale.
Fault Indicators: Loss of VDC power (analog signal drops to 0 mA).
Low electrolyte (analog signal drops to 2 mA; 0 mA on request).
Sensor removed (analog signal drops to 2 mA; 0 mA on request).
Operating Temperature:14° to 113°F (-10° to +45°C); consult PureAire for lower operating temperatures.
Humidity: Sensor dependent; typically 20 to 95% RH; consult PureAire for sensors which
can operate in 100% condensing RH environments.
2.2 Gas Detection System
Type: Renewable GS-DQS electrochemical gas sensor.
Sensor Life: 4 to 5 years under normal conditions.
Detectable Gases: See Appendix for gases, measuring ranges, and sensor part numbers.
2.3 Signal Outputs
Analog Output: DC 4-20 mA
2.4 Electrical Requirements
Power: 24 VDC external power.
Consumption: Approximately 100mA
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2.5 Physical Characteristics
Dimensions: 4.9 (W) x 3 (H) x 3 (D) inches;
125 x 75 x 75 mm
Weight: 1.1 pounds (0.5 kg)
Enclosure Type: General purpose; not intended for explosive atmospheres.
Installation Options: Bulkhead fittings for remote sensor installation.
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3: Installation
3.1 Site Requirements
The Air Check Lite enclosure should be mounted in an area free of vibration and electrical
noise or interference. If possible, avoid areas with high temperatures or relative humidity.
WARNING: The Air Check  Lite 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
The Air Check Lite transmitter is designed primarily for wall mounting and should be
installed at a height convenient for operation, maintenance, and calibration of the instrument.
Allow sufficient space around the transmitter to permit access for maintenance and calibration.
3.2.2 Sensor
IMPORTANT: The Air Check  Lite must be mounted with the sensor pointed
directly down. Do not install with the sensor at greater than a 30° angle from
vertical.
The 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.
Air flow within the monitored area, the characteristics of the target gas (lighter or heavier than
air), and the position of work stations and personnel should all be considered in determining the
most suitable installation location. The sensor should be mounted. Fittings for bulkhead
installation are available; consult PureAire.
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3.3 Sensor Installation
IMPORTANT: Be careful not to turn the sensor or touch the membrane on the
bottom of the sensor during installation.
IMPORTANT: Be sure to remove the jumper from the sensor electronics prior
to installing the sensor. Failure to do so will result in a sensor fault indication
upon startup.
Remove the transmitter cover. It is held in place by captive screws mounted in
each of its four corners.
Insert the sensor cable through the strain relief and into the transmitter
housing.
Connect the 5-conductor sensor cable to the 5-pin Phoenix connector on
the transmitter PCB per the following table:
NOTE:The terminal block may be removed from the printed circuit
board to make these connections. Be sure to replace the terminal block
securely once all connections have been made.
Sensor Cable Type
Wire Color
Location
5-Wire Sensor Cable
Black
White
Red
Green
Yellow or Brown
Terminal 1
Terminal 2
Terminal 3
Terminal 4
Terminal 5
NOTE: This is a keyed connector. Twisting the connector will damage it.
4. Connect the sensor cell male connector into the GS-DQS sensor cell. Align the connector
properly, plug it in, and turn the knurled locking ring until tight
Sensor cell
5-pin
connector
Sensor cell connector
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3.4 Wiring The Air Check Lite uses 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 is recommended for the connection. The
maximum permissible cable length is 0.62 miles (1 km).
The analog out and VDC power in connections are made on the terminal block
inside the transmitter housing.
These connections are made as follows:
Pin #
Connection
Description
1
Power
DC +24V Input
2
Signal Out
4-20mA Output
3
Common (Signal Ground)
0V
IMPORTANT: If connecting directly to a 24VDC power source, you must
use a 100-ohm resistor between pins 2 and 3 to simulate a load. Without
this resistor the Air Check Lite will not operate properly.
3.5 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.
The instrument should now be operating properly.
Power/Analog Out
Terminal Block
+= 24VDC Power
MA = 4-20mA signal
output
(connects to PLC)
C= Common signal
ground
Green LED is
illuminated when
24VDC power and
4-20mA are
terminated
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4: Normal Operation
The Air Check Lite is a single point monitor designed for the continuous detection and
measurement of hazardous gas leaks.
4.1 Signal Outputs
The Air Check Lite outputs a continuous 4-20 mA analog signal proportional to the measured
concentration of the target gas. 4 mA represents 0 ppm; 20 mA represents the top of the
measuring range for the installed sensor.
4.2 Instrument Faults
The Air Check Lite 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 as follows:
Condition
Analog Signal
Sensor cell removed
Analog output drops to 2 mA (0 mA on request)
Electrolyte in sensor low
Analog output drops to 2 mA (0 mA on request)
Power to transmitter lost
Analog output drops to 0 mA
Transmitter cable cut
Analog output drops to 0 mA
4.3 Routine Maintenance Schedule
Continuous gas detection systems depended upon to measure and detect hazardous gas leaks in
the workplace require periodic maintenance to ensure proper operation. The frequency with
which this routine maintenance is required depends on the environment, since temperature,
humidity, gas concentrations, and dust all affect system operation.
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.
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4.3.1 Routine Visual Checks
Items to check
Check for power and proper operation
Condition / status when
operating properly
Unit should be outputting a 4 mA signal when no
gas is present. On instruments with a digital
readout, display should also show 0 when no gas
is present.
Corrective actions
If analog signal (or digital display) is higher than 4
mA in a zero gas condition, adjust as required to
the environment
4.3.2 Recommended Routine Maintenance Schedule
Routine Visual Checks Monthly
Electrolyte Replacement Every 6 months*
Sensor O-ring and Membrane Replacement Every 6 months*
Sensor Calibration Every 6 months
*Hydrogen cell can operate 1-2 years between recharges.
4.4 Loss of Power Indicator
In the event the Air Check Lite loses VDC power, the 4-20 mA analog output signal drops to
0.
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5: Maintenance & Calibration
Maintenance and calibration should be performed only by qualified personnel.
5.1 Sensor Cell Removal and Installation
5.1.1 Sensor Removal
1. Remove the sensor protective sleeve by rotating counter-clockwise
(right to left).
2. Loosen the threaded connector holding the sensor cable to the sensor.
3. Unplug the sensor.
CAUTION: Do not twist the sensor; pull straight down.
CAUTION: Avoid spilling electrolyte out of the small opening on the side of the
sensor.
IMPORTANT: Do not touch the membrane at the bottom of the sensor. Oil from
your hands or fingers will adversely affect performance.
5.1.2 Sensor Installation
IMPORTANT: Be sure to remove the jumper (shorting wire) from the
sensor prior to installation. It is located to the left of the zero and span
potentiometers.
IMPORTANT: Be careful not to turn the sensor or touch the membrane on
the bottom of the sensor during installation.
1. Remove the jumper (shorting wire) from the sensor electronics. It is located
to the left of the zero and span potentiometers.
2. Plug the sensor into the receptacle on the sensor cable and
thread/tighten the knurled connector.
3. Screw the sensor protective sleeve onto the sensor. Do not over-
tighten.
Shorting Plug
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5.2 Electrolyte Replacement
CAUTION: PureAire recommends wearing protective gloves and safety glasses
when replacing sensor electrolyte. Be sure to adhere to your facility’s chemical
handling guidelines and procedures.
1. Remove the sensor as outlined in section 5.1.1.
2. Place your finger over the pressure compensation port and turn the
sensor upside down. Remove the box nut, membrane retainer ring,
membrane,
O-ring, and silicon sheet (depending on sensor model).
Box Nut
Membrane Retainer Ring
Membrane
O-ring
Sensing Electrode
Silicon Sheet
3. Place the sensor over the beaker as shown and pour the old electrolyte into
the beaker. Some will remain in the sensor until the pressure compensation
plug is removed. Remove the milli seal covering the plug and then the plug
to release the electrolyte into the beaker.
Pressure
Compensation
Screw
Beaker for
Old Electrolyte
4. Hold the sensor in your hand with the sensing electrode up. Hold a
piece of paper tissue over the pressure compensation port with your
thumb. Pour
10 cc’s of fresh electrolyte into the sensor and rinse. Discard into the
beaker.
Pressure
Compensation
Screw
NOTE: The Pressure
Compensation Screw
has a Teflon membrane
fixed to the inside of the
screw.
Never remove this
membrane.
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Sensing Electrode
Nozzled Electrolyte
Bottle
Pressure Compensation Port
Electrolyte
5. Wipe the sensing electrode and the surrounding area with a dry paper tissue.
Sensing Electrode
Paper Tissue
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6. Place a new silicone sheet (if used) and O-ring on the sensor. Make sure that
the area is dry of electrolyte.
Silicon Sheet
O-ring
7. Apply a drop of electrolyte on the sensing electrode.
Enlarged View
Drop of
Electrolyte
Sensing
Electrode
8. Place a new membrane on the sensor, with the bead of electrolyte between
the electrode and the membrane.
Enlarged
View
Mmebrane
Electrolyte
Bead
Sensing
Electrode
Mmebrane
NOTE: Do not touch membrane with bare fingers. Oil from your fingers may
adversely affect performance.
9. Place the retainer ring over the membrane and then place the box nut over the
retainer ring. Turn box nut clockwise until hand tight; continue tightening
until the box nut can no longer be moved by hand. CAUTION: Sensor cell
response will be affected if box nut is too loose.
Membrane
Membrane
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Box Nut
Mmebrane
Retainer
Ring
Membrane
10. Hold the sensor in your hand with the electrode down. Pour fresh electrolyte
in until it reaches the MAX. mark.
max.
Enlarged
View
Pressure Compensation Port
Nozzled Bottle
Electrode Level
Mark
NOTE: MAX. level differs from sensor to sensor.
Membrane
Retainer
Ring
Electrolyte Level
Mark
Pressure Compensation Port
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