Cool Air LBW-420-LEL User manual

LBW-420-LEL (24 VDC powered)

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Ammonia Leak Detector
TABLE OF CONTENTS
IMPORTANT—READ THIS FIRST .................................................................................. 1
CAUTIONS........................................................................................................................... 2
AVOIDING UNWANTED ALARMS OR SHUTDOWNS ............................................................. 2
INTRODUCTION ................................................................................................................. 3
STANDARD FEATURES..................................................................................................... 3
PARTS DESCRIPTION ....................................................................................................... 3
FRONT PANEL DISPLAY ..................................................................................................... 3
FRONT PANEL-MOUNTED CIRCUIT BOARD...................................................................... 5
SERVICE SWITCH JUMPER (SERVICE MODE) ................................................................... 5
THE “ENTER”, “UP”, AND “DOWN” PUSHBUTTONS..................................................... 6
ROTARY SELECTOR SWITCH ............................................................................................. 6
ENCLOSURE-MOUNTED CIRCUIT BOARD ......................................................................... 7
POWER................................................................................................................................ 7
JUMPER J3.......................................................................................................................... 7
Jumpers.......................................................................................................... 8
RELAYS............................................................................................................................... 8
RELAY STATUS LEDS........................................................................................................ 8
OUTPUT CONTACTS ........................................................................................................... 9
4–20 MAANALOG OUTPUT................................................................................................ 9
4TO 20MAWIRING.......................................................................................................... 9
INSTALLATION AND SETUP ......................................................................................... 12
PROGRAMMING AND OPERATION ............................................................................ 13
PROGRAMMING THE AMMONIA ALARM SET POINT ...................................................... 13
MANUAL RESET OF THE ALARM CONDITION................................................................... 13
SETTING THE SERVICE MODE TIMEOUT......................................................................... 14
PROGRAMING THE 4TO 20MARANGE ............................................................................ 14
TEST AND CALIBRATION.............................................................................................. 15
TESTING THE DETECTOR................................................................................................. 15
TESTING THE DETECTOR................................................................................................. 15
Zero ............................................................................................................. 16
Span ............................................................................................................. 17
TECHNICAL SUPPORT ................................................................................................... 19
WARRANTY ....................................................................................................................... 20
LBW-420 SPECIFICATIONS............................................................................................ 23
IMPORTANT—READ THIS FIRST

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PLEASE READ AND UNDERSTAND THIS SECTION
BEFORE INSTALLING AND OPERATING THE LBW-
420-LEL DETECTOR
CAUTION:
After applying power, test the detector to ensure it is operating
correctly. Be sure the detector has been powered for at least 10
minutes before testing.
Do not store this manual inside the detector, as this
might result in damage to components from excessive
heat.
ADEQUATELY COVER THE DETECTOR SENSOR
DURING WASHDOWN, AND AVOID SPRAYING THE
WASHDOWN LIQUID DIRECTLY ONTO THE SENSOR
Avoiding unwanted Alarms or shutdowns
To avoid nuisance alarms, place the detector in service mode
before:
•Programming the alarm set point.
•Performing maintenance, repairs, testing, or calibration.
•Performing refrigeration system maintenance.

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INTRODUCTION
The Cool Air Incorporated LBW-420-LEL Detector is a state-of-
the-art ammonia leak detector that detects and displays ammonia
concentrations of 0 to 9.9%. It comes equipped with a long-life
ammonia sensor that has a quick and accurate response to ammonia
concentrations.
The Cool Air Incorporated LBW-420-LEL has a fully isolated DC
to DC power supply, allowing the LBW-420-LEL to be powered
from the same DC supply as the 4-20 mA monitoring circuits
without concern for ground isolation.
The LBW-420-LEL requires a DC supply voltage between 18- and
36-volts DC.
The LBW-420-LEL can be configured to supply power to the 4-20
mA circuit(s) or can operate as a fully isolated 4-20 mA sensor.
Refer to 4–20 mA Analog Outputs for more details.
The Cool Air Incorporated LBW-420-LEL can be optionally
equipped with an AC to DC converter to allow operating the
detector with 100 to 240VAC input.
STANDARD FEATURES
All LBW-420-LEL’s come with these additional standard features:
•Programmable Alarm set point.
•Selectable Service Mode timeout.
•4-20 mA analog output signals, for ammonia which can
communicate directly with computer systems such as
PLC’s.
•Normally-open, normally-closed contacts for
communicating with common industry alarm systems.
PARTS DESCRIPTION
Front Panel Display

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The front panel display is comprised of a digital display and a series
of labeled indicating LED’s. The seven-segment, two-digit display
indicates a variety of information, such as ammonia concentration
and more, depending on the position of the rotary selector switch.
Ammonia concentration is displayed in percent ammonia. The
LEDs provide an indication of ammonia concentration and alarm
status at a glance.
Alarm indication
All Relays will be
active when this is on.
Alarm disabled
indication. All relays
will be deactivated when
this LED is on.
Two-digit seven segment display.
In normal operating mode this
will display the ammonia
concentration. It will also be use
in setting options and calibration.

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Front Panel-Mounted Circuit Board
The front panel-mounted circuit board contains the controls
necessary for programming and operating the detector. Each
control is described in detail below. When the detector enclosure is
open, this circuit board is on the left, attached to the front panel.
NOTE: The service switch may be a jumper instead of the switch.
Service Switch Jumper (Service Mode)
The detector can be set to one of two modes: normal operating
mode or service mode. The detector is in normal operating mode
when the service jumper is in the “OFF” position. When the service
jumper is in the “ON” position, the detector continues to function as
usual, however the alarm, pre-alarm, and auxiliary relays are
disabled as well as the 4 to 20mA signal is set to 4ma (0%). This
allows the detector to be serviced, tested, and calibrated without
tripping the alarm relays and setting alarms or causing shutdowns.
When the detector is in the service mode, “Alarms Disabled” LED
will be illuminated (service jumper “on”). This is done as a
reminder to set the jumper back to “off” when service is done. If
the service jumper is not returned to the off it will automatically
return to an as off state after a selected amount of time. The factory
default is 15 minutes.
See “Setting the Service Mode Timeout”
LBW-420-LEL Control Display board
Service Switch Jumper
Enter push button switch
Program mode (SET1) Jumper
UP push button switch
Down push button switch
Menu rotary switch

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The “ENTER”, “UP”, and “DOWN” Pushbuttons
The “UP” and “DOWN” buttons are used for setting the digital
display to the desired value, and the “ENTER” button is used for
programming a value previously set on the digital display. These
buttons are used when programming: the set points, configuring
other options, they are also used during calibration of the detector.
Rotary Selector Switch
The rotary selector switch (labeled “MENU SELECT” on the front
panel-mounted circuit board) is used for performing functions such
as:
•Setting the information displayed on the front panel
•Programming set point
•Displaying system information
•Calibrating the detector
When the detector is in operation, this switch is typically set to
position “0” to continuously display ammonia concentration.
Use the following chart to select the switch position for the desired
function:
To:
Set the Rotary
Selector Switch to:
Display ammonia concentration in percent
0
Display ammonia concentration in percent
1
Display the firmware revision
2
Program the ammonia alarm set point
3
Factory Use
4
Factory Use
5
Factory Use
6
Factory Use
7
Factory Use
8
Factory Use
9
Note: If the rotary selector switch is left in a position other than
“0” for more than 5 minutes without pushing an “UP”, “DOWN” or
“ENTER” button, the digital display will begin to display ammonia
concentration. If this happens, return the selector switch to the “0”
position, then set the switch to the desired position. For example, if
you set the rotary selector switch to position “3” to program the
alarm set point, and if, after 5 minutes of inactivity the display
reverts to displaying ammonia concentration, move the switch to
“0”, then back to “3” to continue programming the alarm set point.

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Caution: Before closing the detector enclosure, be sure to
return the rotary selector switch to position “0” to
correctly display ammonia concentration.
Additional functions are available through the rotary selector switch
when the jumper (labeled “SET1”), located below the rotary
selector switch on the front panel-mounted circuit board, is
installed:
To:
Set the Rotary
Selector Switch to:
Factory Use
0
Factory Use
1
Display the firmware revision
2
Program the ammonia sensor Range
3
Set the Service Mode Time out
4
Factory Use
5
Factory Use
6
Factory Use
7
Calibrate the detector fine adjust
8
Calibrate the detector course adjust
9
Enclosure-Mounted Circuit Board
The Enclosure Mounted Circuit board contains the relays, output
contacts and termination points for connecting to external
equipment. When the detector enclosure is open, this circuit board
is on the rear wall of the enclosure. The enclosure-mounted circuit
board is shown in the following picture and described in detail
below.
Power
Power for the LBW-420-LEL must be a DC voltage between 18 and
30 volts with a current rating of at least 0.5 amps at 24 volts. Power
is connected to terminal block J2.
Jumper J3, Ammonia signal
Jumper J3 (ammonia signal) configures the LBW-420-LEL to use
either an external power supply for the Ammonia 4-20 mA circuit
or to use an on board 30-volt DC supply for the 4-20 mA circuits.
With the jumper in the leftmost position, connecting pins 2 to 3 (as

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shown in the picture on the next page) 4-20mA power is supplied by
the on-board supply.
With the jumper in the rightmost position, connecting pins 2 to 1
(opposite of picture) 4-20 mA power must be supplied by an
external supply.
Jumpers J3 must be installed in either position. If the jumper is
removed, the 4-20 mA circuit(s) will not function.
Jumper J4 is not used
Jumper Required
Relays
The detector has three miniature printed circuit board relays: the
alarm, pre-alarm (early warning), and the auxiliary relays. In the
normal operating mode, the relays are energized in a normally-open
state. If a loss of power to the detector occurs, the relays will de-
energize and the alarms, if connected, will sound. When the detector
goes into alarm all three relays de-energize at the same time.
Relay Status LEDs
Each relay has a surface-mounted LED associated with it that
indicates the status of the relay. A relay is energized (a non-alarm
condition) when its LED is lighted (green), and de-energized (an
alarm condition) when the LED is not lighted.

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External Connections
Contacts for external connections:
•4–20 mA outputs for ammonia level
•Auxiliary Relay contacts
•Alarm Relay contacts
•Pre-alarm Relay contacts
•LBW-420-LEL DC Power
4–20 mA Analog Outputs
The detector has a 4-20 mA analog output that allows it to
communicate with external devices such as computers, PLCs, and
digital displays. The output conforms to ISA S50.01 ratings, Type
2L and Type 2H (two-wire).
The ammonia level detector output current (TB2, “Sensor 4-
20mA” terminals on lower left of Enclosure Mounted Circuit
Board) is proportional to ammonia % with the proportionality
constant dependent on the range. The % value can be determined
using one of the following formulae:
% NH3 = .041667 (I – 4) 0 to 1% Range
% NH3 = .083334 (I – 4) 0 to 2%Range
% NH3 =.4166667(I – 4) 0 to 10% Range
Where % NH3 equals ammonia concentration in percent and I equal
the output current in mA. For example, if the current is 4 mA, then
the ammonia concentration is 0 %. If the current is 20 mA, then the
ammonia concentration is 1% (1% range), 2% (2% range), and 10%
(10% range)
4 to 20mA WIRING
For this configuration, with the jumper J3 in the leftmost position
(which connects pins 2 & 3) power for the 4-20 mA circuit is
provided by the LBW-420-LEL. This circuit is shown below. The
power supply must supply all power for the LBW-420-LELplus the
4-20 mA circuit. Refer to the specifications page for the power
requirements for the LBW-420-LEL. The voltage drops across the
detector and the receiver together must not exceed the power supply
voltage. This circuit is shown in figure 1 below:

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FIGURE 1
Wiring Diagram: LBW-420-LEL with (2) – 24 VDC
Power Supplies
In this configuration, with the jumper J3 in the rightmost position
(which connects pins 1 & 2), power for the LBW-420-LELis
supplied by the 24 VDC power supply #1 only. The power supply
must supply all power for the LBW-420-LEL. Refer to the
specifications page for the power requirements for the LBW-420-
LEL.The power for the 4-20 mA circuit is supplied by the 24 VDC
power supply #2. The 4-20 mA circuit is a simple series circuit that
includes the LBW detector, a power supply, and the receiving
device. It is recommended that a 24 VDC low-noise power supply
be used for this application, although power supplies providing a

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minimum of 10 VDC to a maximum 30 VDC can be used. The
voltage drop across the detector and the receiver together must not
exceed the power supply voltage. This circuit is shown in Figure 2
below:
FIGURE 2
For the LBW-420-LEL, the maximum allowable resistance in the
receiving device must not exceed Rmax using this formula:
Rmax = 50 (Vs – 7.5)
Where Vs is the supply voltage in volts DC for the 4-20 mA circuit.
For example, with a supply voltage of 24 VDC, the maximum
allowable resistance is 825 Ω.

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INSTALLATION AND SETUP
Caution: Do not apply power to the detector until instructed to
do so.
The detector comes with four mounting feet, packaged in the
detector enclosure for shipment. Use the directions that accompany
the mounting feet for mounting the detector enclosure.
The detector should be mounted in a location where ammonia leaks
are most likely to occur, such as near valve groups, compressors,
and refrigeration coils. Be sure the detector is visible and easily
accessible. Avoid locating the detector where it might be damaged
during wash-down.
When power is applied to the detector the display will stay blank for
10 seconds. This is normal. This is ensuring no monitoring for
ammonia is performed until the sensor is stable.
The detector is calibrated and programmed at the factory. To
program the detector for its specific installation, follow these steps
in the order given:
1. Open the detector enclosure and place the detector in service
mode by moving the service jumper to the “ON” position.
2. Apply power to the detector and allow the sensor to warm to
normal operating temperature (at normal operating temperature,
the display will read “0” and all Alarm LEDs will be unlit).
3. Program the ammonia High alarm set point. See the next
section on programming the ammonia high alarm set point.
4. Be sure the displayed ammonia concentration is below the
programmed alarm set point, return the detector to normal
operating mode by moving the service jumper to the “OFF”
position.
5. Test the detector to ensure it is operating correctly (but allow at
least 10 minutes after power is first applied to the detector
before testing). See the section on testing the detector.

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PROGRAMMING AND OPERATION
The LBW-420-LEL detector is easy to program and operate.
Follow the instructions in this section to:
•Program the ammonia alarm set point
•Set the 4 to 20mA range
•Set the Service mode time out
Programming the Ammonia Alarm Set Point
The Alarm set point can be set from .1% to 9.9% in .1% increments.
1. Open the detector enclosure and move the service jumper to the
“ON” position.
2. Set the rotary selector switch to position “3”.
3. Press the “UP” or “DOWN” button until the desired set point
concentration in % is displayed.
4. Press and hold the “ENTER” button for at least 2 seconds. The
new set point is now programmed.
5. Return the rotary selector switch to the desired position.
6. Be sure the ammonia concentration reading is below the
alarm set point, then move the service jumper to the “OFF”
position and close the detector enclosure.
Manual reset of the alarm condition
Once the ammonia concentration has reached the alarm set point,
the alarm light will come on and all three relays will activate. These
conditions will remain until the detector has been manually reset.
To reset the detector, follow these steps:
1. Install the jumper on the jumper pins (labeled “SET1”)
located below the rotary switch on the front panel-mounted
circuit board
2. Set the rotary menu selector switch to position “5”
3. Press the “ENTER” button for two seconds

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4. The alarm light should go off and the relays should reset
5. Return the rotary menu selector switch to position “0”
6. Remove (move to one pin only) “SET1” jumper
The detector is now ready to monitor ammonia again.
Setting the Service Mode Timeout
If the service jumper is not returned to off, you can change how
long the detector stays in service mode before returning to normal
operating mode.
With the SET jumper on and the Rotary Switch in position 4 you
can use the up and down buttons to select either;
1 – After 1 hour in the on position the detector will return to normal mode.
2 – After 2 hours in the on position the detector will return to normal mode.
4 – After 4 hours in the on position the detector will return to normal mode.
8 – After 8 hours in the on position the detector will return to normal mode.
Once you have selected the desired service mode timeout you must
hold the ENTER button for two seconds before removing the SET 1
jumper or changing the rotary switch.
Programing the 4 to 20mA range
The ammonia level 4-20 mA signal can be scaled to one of three
ranges, either 0-1% (r1), 0-2% (r2), or 0-10% (r3). To program the
4-20 mA range, follow these steps:
1. Open the detector enclosure and move the service jumper
to the “ON” position.
2. Install the jumper on the jumper pins (labeled “SET1”)
located below the rotary switch on the front panel-mounted
circuit board.
3. Set the rotary selector switch to position “3”. The display
will indicate the current range, either “r1 (0 to 1% range),
“r2” (0 to 2% range), “or “r3” (0 to 10% range).

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4. Press the “UP” or “DOWN” button until the display
indicates the desired range.
5. Press and hold the “ENTER” button for at least 2 seconds.
The new range is now programmed.
6. Remove the jumper and return the rotary selector switch to
the desired position.
7. Move the service jumper to the “OFF” position and close
the detector enclosure.
TEST AND CALIBRATION
Be sure to follow all codes and company procedures that pertain to
the maintenance, repair, testing, and calibration of all safety
equipment, including this detector. At a minimum, the detector
must be calibrated at least once a year to ensure it is detecting and
displaying ammonia concentration accurately.
The detector is initially calibrated and programmed at the factory.
However, if a new ammonia sensor is installed, the detector must be
calibrated. All tests and calibrations must be recorded.
Not installing, maintaining, testing, or calibrating the detector
according to the schedules and procedures in this manual will
automatically void the warranty.
Testing the Detector
The detector hardware and the connected system response can be
tested without exposing the sensor to ammonia. With the SET 1
jumper off, rotate the rotary switch to position 5. Pressing the
“DOWN” button will force the detector to simulate an ammonia
concentration equal to the LOW Alarm Set Point. Pressing the “UP”
button will force the detector to simulate an ammonia concentration
equal to the HI Alarm Set Point. The 4 to 20mA output current will
indicate the simulated ammonia concentration according to the 4 to
20mA range selected. If the relay is set to latch, you will need to
reset the relay after each test.
To test the detectors response to ammonia (for best results, allow at
least 20 minutes after first applying power to the detector):

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1. Open the detector enclosure and move the service jumper to the
“ON” position, if needed. This step deactivates the Pre-Alarm,
Alarm, and Auxiliary relays so that any attached strobe lights,
horns, and/or monitoring systems are not activated. In some
applications, if alarming is required, leave the service jumper in
the “OFF” position.
2. Attach the calibration adaptor to the sensor and flow the test
gas at no greater than .5Lpm.
3. Check the following:
•When the ammonia concentration reaches the Alarm
set point the Alarm LED (red) will come on.
•Digital display shows an increasing concentration of
ammonia in %.
•4-20 mA output signal shows an increasing value that
corresponds to the digital display.
4. Remove the ammonia sample.
5. Wait until the ammonia concentration reading is below the
alarm set point, then move the service jumper to the “OFF”
position and close the detector enclosure. Remember, this step
is only required if the service jumper was moved to the “ON”
position in step # 1 above. Testing is now complete.
NOTE: If the detector was not put in service mode and went
into alarm, you will need to perform a manual reset once the
display reads lower than the alarm set point.
See “Manual reset of the alarm condition” section
Calibrating the Detector
Adjusting the Zero reading on the Detector
Follow these instructions to adjust the zero reading on the detector:
1. Open the detector enclosure and move the service jumper to
the “ON” position, if needed. This step deactivates the pre-
alarm, Alarm, and Auxiliary relays so that any attached strobe
lights, horns, and/or monitoring systems are not activated. In
some applications, if alarming is required, leave the service
jumper in the “OFF” position.
Amplifier Module (inside the housing)
Sensor
connection
Zero adjust
Pot
Connection to
Control Display
Board
For factory use only

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2. Adjust ZERO adjust pot until the display reads zero.
NOTE: If the detector was not put in service mode and went
into alarm, you will need to perform a manual reset once the
display reads lower than the alarm set point.
See “Manual reset of the alarm condition” section
Adjusting the Span reading on the Detector
Follow these instructions to calibrate the detector for span:
3. Open the detector enclosure and move the service jumper to
the “ON” position, if needed. This step deactivates the pre-
alarm, Alarm, and Auxiliary relays so that any attached strobe
lights, horns, and/or monitoring systems are not activated. In
some applications, if alarming is required, leave the service
jumper in the “OFF” position.
4. Install the jumper on the jumper pins (labeled “SET1”) located
below the rotary selector switch on the front panel-mounted
circuit board.
5. Set the rotary selector switch to position “9”.
6. Apply span gas certified span gas at 0.3 L/min (span gas must
be in air, not nitrogen or another carrier). until a stable
ammonia concentration reading is displayed. It might take
several Seconds for the reading to stabilize this should be at a
maximum 60 seconds.
7. Press the “UP” or “DOWN” button until the display indicates
the concentration of the known sample. For example, if the
sample ammonia concentration is 1%, press the “UP” or
“DOWN” button until the display indicates 1%.
8. If a fine adjustment is necessary Set the rotary selector switch
to position “8” and repeat step 7.
9. Press and hold the “ENTER” button for at least 2 seconds.
10. Remove the span gas.
11. Move the jumper on the jumper pins (labeled “SET1”) located
below the rotary selector switch on the front panel-mounted
circuit board to just one pin.
12. Wait until the ammonia concentration reading is below the
alarm set point, then set the rotary selector switch to the
desired position (typically “0” or “1”) and the service jumper
to the “OFF” position and close the detector enclosure.

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Remember, this step is only required if the service jumper was
moved to the “ON” position in step # 2 above. Calibration is
now complete.
NOTE: If the detector was not put in service mode and went
into alarm, you will need to perform a manual reset once the
display reads lower than the alarm set point.
See “Manual reset of the alarm condition” section