Alnor AirGard 335 User manual

AirGard®335
Fume Hood Monitor
OWNER’S MANUAL

LIMITATION OF WARRANTY AND LIABILITY
Seller warrants that this product, under normal use and service as described in the
operator's manual, shall be free from defects in workmanship and material for a period of
twenty four (24) months, or the length of time specified in operator's manual, from the date of
shipment to the customer. This limited warranty is subject to the following exclusions:
a. Batteries and certain other components when indicated in specifications are warranted for
a period of 90 days from the date of shipment to the customer.
b. With respect to any repair services rendered, Seller warrants that the parts repaired or
replaced will be free from defects in workmanship and material, under normal use, for a
period of 90 days from the date of shipment to the customer.
c. Seller does not provide any warranty on finished goods manufactured by others. Only the
original manufacturer's warranty applies.
d. Unless specifically authorized in a separate writing by Seller, Seller makes no warranty
with respect to, and shall have no liability in connection with, any goods which are
incorporated into other products or equipment by the Buyer. All goods returned under
warranty shall be at the Buyer’s risk of loss, Seller’s factory prepaid, and will be returned
at Seller’s risk of loss, Buyer’s factory prepaid.
The foregoing is IN LIEU OF all other warranties and is subject to the conditions and
LIMITATIONS stated herein. NO OTHER EXPRESS OR IMPLIED WARRANTY OF
FITNESS FOR PARTICULAR PURPOSE OR MERCHANTABILITY IS MADE.
THE EXCLUSIVE REMEDY OF THE USER OR PURCHASER, AND THE LIMIT OF THE
LIABILITY OF SELLER FOR ANY AND ALL LOSSES, INJURIES, OR DAMAGES IN
CONNECTION WITH THIS PRODUCT (INCLUDING CLAIMS BASED ON CONTRACT,
NEGLIGENCE, STRICT LIABILITY, OTHER TORT, OR OTHERWISE) SHALL BE THE
RETURN OF THE PRODUCT TO THE FACTORY OR DESIGNATED LOCATION AND THE
REFUND OF THE PURCHASE PRICE, OR, AT THE OPTION OF SELLER, THE REPAIR
OR REPLACEMENT OF THE PRODUCT. IN NO EVENT SHALL SELLER BE LIABLE FOR
ANY SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES. SELLER SHALL NOT BE
RESPONSIBLE FOR INSTALLATION, DISMANTLING, REASSEMBLY OR
REINSTALLATION COSTS OR CHARGES. NO ACTION, REGARDLESS OF FORM, MAY
BE BROUGHT AGAINST THE SELLER MORE THAN ONE YEAR AFTER THE CAUSE OF
ACTION HAS ACCRUED.
The purchaser and all users are deemed to have accepted the terms of this LIMITATION OF
WARRANTY AND LIABILITY, which contains the complete and exclusive limited warranty of
Seller. This LIMITATION OF WARRANTY AND LIABILITY may not be amended or modified
nor may any of its terms be waived except by a writing signed by an authorized
representative of Seller
Service Policy
Knowing that inoperative or defective instruments are as detrimental to Alnor as they are to
our customers, our service policy is designed to give prompt attention to any problems. If any
malfunction is discovered, please contact your nearest sales office or representative, or call
Alnor’s Customer Service department at [phone] (USA) and (1) 651-490-2811
(International).

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TABLE OF CONTENTS
Section 1 Introduction
General Description...................................................... 3
Component Identification ............................................. 4
Section 2 Installation
Tools Required ............................................................. 7
Mounting the Monitor .................................................. 7
Electrical Wiring........................................................... 8
Section 3 Calibration
Overview .................................................................... 10
Low Alarm Setup ....................................................... 14
Section 4 Normal Operation
Power Up Sequence.................................................... 15
Run Mode ................................................................... 15
Monitor Test ............................................................... 16
Horn............................................................................ 16
Viewing Alarm Set Points .......................................... 17
Changing Alarm Set Points ........................................ 17
High Alarm Disable.................................................... 18
Emergency Purge........................................................ 18
Section 5 Parameter Configuration
General ....................................................................... 19
Configuration Parameters ........................................... 20
CAL — Calibration ..................................................... 21
P01 — Digits Enabled/Disabled .................................. 21
P02 — Unit of Measure ............................................... 21
P03 — Temporary Horn Disable Timer....................... 22
P04 — Caution-to-Alarm Transition Delay Timer ...... 23
P05 — Alarm-to-Caution Transition Delay Timer ...... 24
P06 — Low Alarm Caution Offset .............................. 25
P07 — Dis Input .......................................................... 26
P08 — Alarm Input...................................................... 28
P09 — Relay Output 1................................................. 31
P10 — Relay Output 2................................................. 33
P11 — High Alarm Relay Disable............................... 35
P12 — Night Setback Low Alarm ............................... 36
dEF — Reset Configuration Parameters to Factory
Default Settings........................................................ 37

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Section 6 Troubleshooting and Service
Error Codes................................................................. 38
Troubleshooting Guide ............................................... 39
Service Requests......................................................... 40
Section 7 Mounting Template............................................................ 41

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SECTION 1
Introduction
General Description
Air is drawn into a fume hood by an exhaust system that produces a
differential pressure between the interior of the fume hood and the
surrounding laboratory. The average velocity of the air moving
perpendicular through the front sash opening of the hood is called the
face velocity. Adequate face velocity is necessary to protect fume hood
users by containing all of the contaminants inside the fume hood.
The AirGard®335 continuously monitors fume hood face velocity by
measuring the air velocity of clean air from the room passing through
the air inlet on the front of the monitor. The monitor then reports this
information via audio and visual indicators.
Visual Indicators — An electronic bargraph moves back and forth
through universally recognized red (danger), yellow (caution) and
green (safe) colored zones as the velocity changes. Corresponding
large colored LEDs also illuminate. A digital display can be enabled to
view velocity quantitatively.
Audible Indicator — A continuous audible alarm alerts of a dangerous
situation when the face velocity is in an alarm condition.
Alarm information can be sent to other personnel in a remote location
by means of a relay output.
IMPORTANT: Fume hoods vary in design and performance. Because
each hood installation and its air flow patterns is unique, the AirGard
335 Monitor must be calibrated in the field on the fume hood in which
it is installed.
Read this manual entirely before installing, calibrating, configuring,
and using the AirGard®335. If you need assistance or any further
explanation regarding this instrument, please contact TSI.

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Component Identification
Figure 1 — Front View of Instrument
Analog Bargraph
Status LEDs
(
red,
y
ellow and
g
reen
)
Colored Bands
Digital Display
Up Button
Down Button
Test/Reset
Button
Mounting
Screw
Emergency
Purge Button
Mounting
Screw
Air Inle
t

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Status LEDs Red (Alarm) — Indicates a high or low
airflow alarm;
Yellow (Caution) — Indicates that the
airflow is within the caution zone between
normal and low alarm;
Green (Good) — Indicates that the airflow
is within normal range.
Up Button Up scroll button for configuration and
calibration.
Down Button Down scroll button for configuration and
calibration.
Analog Bargraph Electronic bargraph expands/contracts
through colored zones as the flow velocity
changes.
Colored Bands Red, yellow and green colored bands on
LCD glass correspond to alarm, caution, and
normal zones.
Digital Display Status indicators and icons reflect the status
of monitor features. If digits are enabled,
shows airflow velocity measurement either
in feet per minute or meters per second.
Test/Reset Button Tests the digital display, LEDs, audible
alarm and relay output or, if an alarm is
present, silences the audible alarm. It is also
is used during calibration and configuration.
Emergency Purge Button When configured to operate, activates a
relay that can be used to command the fume
hood damper to open until pressed again.
Air Inlet Guides room air to the sensor.
Mounting Screws Two #6-20 screws secure the monitor to the
fume hood.

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Figure 2—Back View of Instrument
Communications Port For factory use only.
Flow Tube Connects the flexible air hose attached to the
fume hood side wall.
Terminal Block Accepts 14-24 AWG wires. See the
Installation section for wiring the monitor’s
various input/output features.
Power Jack A suitable AC/DC power supply is supplied
with US/Canada units; a 2.1 mm plug with
1.8 m power cord is provided for other
countries.
Flow Tube
Terminal Block
Power Jack
Communications
Port

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SECTION 2
Installation
Tools Required
1. Power Drill
2. Drill bit size #37 (0.104 inch) (2.6 mm)
3. 9/16 inch (14 mm) diameter hole saw for cutting into side wall
4. Reciprocating saw with saw blades for cutting sheet metal
5. Pilot drill sized to fit saw blade
6. Phillips head screwdriver with #1 point
7. Small slotted screwdriver for securing wires to terminal block.
WARNING: If the monitor will be installed on a hood with
Hardiboard™ fiber-cement panels or similar material, use a
special hole saw designed for glass and other hard, abrasive
materials. Failure to do so may shatter or crack the panel.
DANGER: Always wear eye protection when using power tools.
Observe all necessary precautions when installing or repairing
monitors near electrical equipment.
Mounting the Monitor
1. Determine where the monitor will be mounted. Use the cardboard
template supplied as a guide for the size of the installed product
and the hole needed to be cut out of the hood. The cutout required
is 3 inches high by 2 inches wide (76.2 x 50.8 mm), which is the
typical size required for a single switch electrical box. If the
cardboard template is not available, a dimensioned diagram is at
the back of this manual (see Section 7).
2. Using the template, mark off the 3 inch high by 2 inch wide (76.2
x 50.8 mm) hole necessary to clear the back enclosure portion of
the monitor. Mark off the two mounting screw hole locations.
3. Drill a pilot hole in each of the four corners. Use the saw to cut out
the hole. A suitable nibbling tool may also be used.
4. Drill the two #37 (0.104 inch) (2.6 mm) mounting screw holes.

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5. Drill one 9/16 inch (14 mm) diameter hole in the size wall of the
fume hood approximately 6 inches (152 mm) behind the sash and
1 inch (25.4 mm) above the sash bottom when it is at its true fully
open position. Insert the side wall adapter from the inside of the
hood and securely lock it in place from the back with the locking
ring.
6. Connect the input/output signal wiring, if required, to the terminal
block on the back of the monitor. See the Electrical Wiring below.
7. Connect one end of the supplied air hose to the side wall adapter.
Route the hose as necessary to avoid kinks and bends which can
affect proper air flow. Trim slightly if required. Firmly connect the
other end to the flow tube on the back of the monitor.
8. Connect the power cord to the power jack.
9. Screw the monitor to the fume hood with the self-tapping screws
provided.
10. Plug the power supply into an appropriate electrical outlet.
Electrical Wiring
Power Jack — Power is supplied to the monitor through a power jack
located on the back of the monitor. For units shipped within the United
States and Canada, a suitable AC/DC power supply is supplied with the
unit. Plug the power supply into 120 VAC nominal 60 Hz mains.
For monitors shipped outside the US/Canada, a 2.1 mm plug with a
1.8 m cord is provided. See the Specification section on the inside front
cover for power requirements.
Terminal Block — The monitor has a seven-pin screw terminal block
connector protruding from the back of the monitor. The terminal block
accepts 14-24 AWG wires. These connections are for input/output
features. See the Configuration Parameters section where indicated.
The connections available are described below:
DIS INPUT: This allows you to activate the Test/Reset or Emergency
Purge functions with a remote contact closure or remotely disable the
monitor or change to a lower alarm setpoint during night setback. The
night setback function may be wired to use open or closed contacts.
When wired for “open” contacts, opening the contacts will disable the
monitor; when wired for “closed” contacts, closing the contacts will
disable the monitor. The connection should be made through a switch
to the INPUT COM terminal. See Configuration Parameter P07.

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ALRM INPUT (Alarm Input): This allows you to remotely activate the
Test/Reset or Emergency Purge functions via a contact closure or wire
an external alarm/event into the monitor. The external alarm function
may be wired to use open or closed contacts. When wired for “open”
contacts, opening the contacts will activate the monitor’s alarm; when
wired for “closed” contacts, closing the contacts will activate the
monitor’s alarm. The connection should be made through a switch to
the INPUT COM terminal. See Configuration Parameter P08.
INPUT COM (Input Common): This is the ground used for the DIS
INPUT and ALRM INPUT connections.
RELAY 1 (Relay 1): This relay has contacts that are open in the non-
energized state. It can be configured to close for alarm, caution, or
emergency purge or open for alarm, caution, emergency purge, or loss
of power. See Configuration Parameter P09.
RELAY 2 (Relay 2): This relay has contacts that are closed in the non-
energized state. It can be configured to open for alarm, caution, or
emergency purge or close for alarm, caution, emergency purge, or loss
of power. See Configuration Parameter P10.
2.1mm barrel jack
Use a 9 to 30 V AC/DC
200mA Max. Class 2 power supply
Use 14 - 24 AWG wire
TERMINAL
BLOCK
J1
12
POWER
JACK
J3
34567
5V DC
1 2
DIS INPUT
12
Installation Wiring Diagram
Recommended ALRM INPUT
External
Ratings:
Switch
@0.5mA Max. 0.5A @25V A
C
1A @30V DC
Internal
Relays 1 & 2 are rated for:
INPUT COMMON
RELAY 1 CONNECTIONS (NO) RELAY 2 CONNECTIONS (NC)
This diagram is provided to illustrate the field connections.
Figure 3 – Field Wiring Diagram

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SECTION 3
Calibration
Overview
IMPORTANT: Calibration procedures are for a constant volume
hood. If you have a VAV hood, call TSI for the calibration procedure.
The fume hood monitor must be calibrated before first use and checked
annually thereafter. The calibration is stored in the non-volatile
memory of the instrument and is not lost when the monitor loses
power.
Fume hoods vary in design and performance. Because each hood
installation and its air flow patterns is unique, this monitor must be
calibrated in the field on the fume hood in which it is installed.
DANGER: Calibration and configuration of this monitor must be
performed by qualified personnel. Proper guidelines for
monitoring any ventilation apparatus are established on the
basis of toxicity or hazards of the materials used, or the
operation conducted within the ventilation apparatus. Personnel
calibrating this monitor must be completely aware of the
regulations and guidelines specific to its application.
If you need a reference on performing traverses on fume hoods, please
consult ANSI/ASHRAE 110-1995 Method of Testing Performance of
Laboratory Fume Hoods, section 6.2 Face Velocity Measurements.
Tools Required
1. Calibrated thermo-anemometer. Suggested instruments include the
Model 9870 or Model 8570.
2. Small pointed tool to press the recessed Up and Down buttons. A
straightened paper clip works well.
Procedure
1. Ensure that the monitor is properly installed. The flexible air hose
should be attached securely to both the fume hood side wall and
the back of the monitor.
2. The power supply plug should be firmly in the power jack on the
back of the monitor and the power supply should be plugged into

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an appropriate live electrical outlet. The monitor must be warmed
up for at least 10 minutes to reach a stable operating temperature.
NOTE: For the two point calibration, high and low face velocities
need to be determined. These two values must be between 50 and 250
fpm (0.25 and 1.27 m/s). An accurate calibration requires that the low
and high calibration points be separated by an adequate velocity.
Therefore, a minimum separation value is set at the factory. After
calibration is completed at the low point, the display will jump ahead
to the suggested value for the high calibration point. Typical values for
calibration are 70 fpm (0.36 m/s) for the low and 150 fpm (0.76 m/s)
for the high.
3. While the monitor warms up, use a calibrated thermo-anemometer
to determine the velocity through the face of the hood by taking
two detailed traverses. Take one traverse at low flow with the sash
true full open (beyond the sash stop) and another at high flow with
the sash at 12 inches (204 mm). For each traverse, divide the area
under the sash into equal areas and measure at the center of those
areas. Do not move more than 6 inches (152 mm) between
readings. A minimum of sixteen readings must be taken per
traverse. Record the average velocities and the sash heights where
they are taken.
4. Move the sash back to the true full open position (i.e., the point
where the low flow face velocity traverse was conducted).
5. Press and hold the Test/Reset button until you hear a double beep
and see CAL displayed.
NOTE: This Calibration initialization sequence takes approximately
10 seconds, during which the display will be fully lit (all segments on)
for about 3 seconds and then blank (all segments off) for about 5
seconds before the word CAL appears.
6. Press the Test/Reset button to begin the calibration process. Lo
will be displayed for two seconds and then the low calibration
reference starting point. Use the Up or Down buttons to adjust the
displayed value to match the actual measured low face velocity
(sash full open).
7. Press the Test/Reset button once the desired value is displayed and
step away from the face of the fume hood. The monitor will count
down 5 seconds (shown on the display) and then take readings for
20 seconds (again shown as a countdown display). This completes
the Lo calibration; Hi will then be displayed for two seconds.

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NOTE: If an error message is displayed at this point, there is problem
with the calibration and the procedure will be terminated. See
Calibration Error Codes below.
8. Move the sash to the 12 inch (305 mm) open position (the point
where the high flow face velocity traverse was conducted).
9. Use the Up/Down buttons to adjust the displayed Hi value to
match the actual measured high face velocity (sash at 12 inch/204
mm open position).
10. Press the Test/Reset button once the desired value is displayed and
step away from the face of the fume hood. The monitor will count
down 5 seconds (shown on the display) and then take readings for
20 seconds (again shown as a countdown display).
11. The monitor now conducts a self-test to determine if the
calibration was successful. If this test indicates that the calibration
was successful, the instrument will emit two quick beeps, store the
new values in memory, and return the display to the CAL
configuration menu selection.
This completes the calibration procedure. To view other parameter
configuration menu selections (see Section 5), press the Up/Down
buttons. To exit and return to the Run mode, press and hold the
Test/Reset button for two seconds.
Calibration Error Codes
If an error occurs during a calibration step, the instrument will emit one
long beep and the display will show an error code.
Error Code Cause
ErL Airflow below the instrument’s measurement range.
ErH Airflow above the instrument’s measurement range.
Err Too much variation in airflow.
Er2 Insufficient difference between the low and high calibration
points.

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If a calibration error is detected, the user must press the Test/Reset
button to acknowledge the error condition. After acknowledgement, the
monitor will return to the CAL configuration menu selection so that
another calibration can be attempted. The incorrect values will not be
stored in memory. The monitor will continue to use the previous
calibration values until a correct calibration is successfully completed.
Suggestions For Obtaining An Acceptable Calibration
ErL — To obtain a slightly higher airflow velocity for the low cal
point, lower the sash a few inches and take another set of velocity
readings. Use this new sash position as the low cal position.
ErH — To obtain a slightly lower airflow velocity for the high cal
point, raise the sash a few inches and take another set of velocity
readings. Use this new sash position as the high cal position.
If the unit displays this error during Calibration, the thermistor is
broken. Return to TSI for service.
Err — To get a more laminar (stable) set of sample readings, check the
following during the 20 second calibration period:
 Make sure no one is walking in front of the hood.
 Make sure doors and windows are not being opened and closed.
 Do not change baffle positions on the hood.
 Check to see if the lab HVAC is cycling on or off, either heating
or air conditioning.
 Compare all readings taken during the traverse to see if any vary
by more than 10 fpm above or below the calculated average (‘fast
spots’ or ‘slow spots’). Hint: Set the thermoanemometer to the
lowest possible time constant.
 Make sure the hose is connected properly to the sidewall of the
hood and the monitor and is not kinked.
 Check for presence of a diffuser or supply grille right above the
hood. If air is being “pushed” toward the front of the monitor, try
diverting or blocking it.
Er2 — Adjust sash positions to achieve either a lower low cal point
(by raising the sash) and/or a higher high cal point (by lowering the
sash).

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Low Alarm Setup
The low alarm setpoint should be established before first use and
checked annually thereafter. The alarm setup is stored to nonvolatile
memory and is not lost when the monitor loses power.
Procedure
1. Verify that the monitor was properly installed.
2. The power supply plug should be firmly in the power jack on the
back of the monitor and the power supply should be plugged into
an appropriate live electrical outlet. The monitor must be warmed
up for at least 10 minutes to reach a stable operating temperature.
3. Once the monitor warms up, note the velocity displayed through
the fume hood. This can be observed without changing the settings
by pressing the Down Button and watching the number that
alternates with the low alarm setting (the default setting is OFF).
4. Press and hold the Down Button for 5 seconds to access the low
alarm setup menu. The current alarm setting will be displayed.
5. Use either the Up or Down Button to change the displayed value to
match the actual desired low alarm point. Press the Test/Reset
button when the desired value is displayed.

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SECTION 4
Normal Operation
Power Up Sequence
On power up, the digital display is initialized and every segment of the
display turned on for two seconds. All three of the LEDs and the horn
are also activated.
After the two seconds has expired, the three LEDs and the horn will
turn off. The version number of the firmware will then be displayed for
two seconds.
Run Mode
An electronic bargraph travels horizontally through universally
recognized red (danger), yellow (caution) and green (safe) colored
zones as the flow velocity changes. Corresponding large colored LEDs
also illuminate.
The green LED indicates a normal airflow condition. The yellow LED)
indicates that the airflow is within the caution zone between normal
and low alarm. The red LED indicates an airflow alarm.
These Good, Caution, and Alarm zones are determined by a user
programmed low alarm set point and set point offset. If the digits are
enabled, the digital display shows the air flow velocity measurement
either feet per minute (fpm) or meters per second (m/s). Over range
measurements are shown as Hi. Under range measurements are shown
as Lo.

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Monitor Test
During normal operation, pressing and holding the Test/Reset Button
for 2 to 5 seconds will turn on all segments on the LCD and all LEDs
as well as the horn and the alarm relay output. To test the emergency
purge feature, press the Emergency Purge button; press it a second time
to turn it off.
Horn
The horn will be activated whenever the Low or High Alarm zone has
been reached (unless the horn has been permanently disabled).
Once the horn has been activated due to an alarm condition, it will stay
on until the condition causing the alarm ceases to exist or the horn is
temporarily or permanently disabled. If the horn is temporarily
disabled, the horn will turn off and not come back on until either the
temporary horn disable timer expires (Configuration Parameter P03) or
another alarm condition is detected. If the horn is permanently
disabled, the horn will not come back on until the horn is re-enabled.
The horn will sound when the sash override input is active and will
remain on until the sash override input is deactivated or the Test/Reset
button is pressed.
The horn will also sound when the Emergency Purge button is pressed
and will remain on until the Emergency Purge button is pressed again
or the Test/Reset button is pressed.
The horn will pulse intermittently when the external alarm input is
active and will remain on until the external alarm input is deactivated.
If the night setback is active (with P12 set to “OFF”), the horn will be
completely disabled in all instances until this input is deactivated. (See
P07 for details)

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Temporary Horn Disable
Pressing the Test/Reset button temporarily silences the horn. The horn
slash through icon will be on the display indicating that the horn is
temporarily disabled. If the horn is temporarily disabled, it will turn off
and not come back on until either the temporary horn disable timer
expires or until the monitor detects another alarm condition. See
Configuration Parameter P03 for programming the timer.
Permanent Horn Disable
The horn may be permanently disabled during normal operation by
pressing and holding the Test/Reset button for five seconds. After five
seconds, the horn slash through icon will continuously flash on the
display indicating that the horn is permanently disabled; the horn will
no longer sound in an alarm zone or when any alarm input is activated.
Removal of power to the monitor does not change this setting; upon
restoration of power, the horn will still be disabled. The horn may be
re-enabled by pressing the Test/Reset button for five seconds. The
flashing horn slash through icon will then be shut off.
Viewing Alarm Set Points
The alarm set points may be viewed during normal operation by
pressing the Up and Down Buttons. The Up Button is to the right of the
green LED. The down button is to the left of the red LED. A
straightened out paper clip works well to access them. If the Up Button
is pressed, the display will toggle between the current reading and the
High Alarm set point. If the Down Button is pressed, the display will
toggle between the current reading and the Low Alarm set point.
The display will toggle between the current reading and the selected set
point until there is no keypad activity for five seconds. At that point,
the monitor will return to normal operation and display the current
airflow reading.
Changing Alarm Set Points
The alarm set points can be changed during normal operation and while
viewing a set point by holding the Up Button (High Alarm) or Down
Button (Low Alarm) for five seconds. When the button is first pushed,
the display will toggle between the current reading and the selected set
point. If the button is held for five seconds, the monitor goes into a
program mode that allows changing the selected set point. The
corresponding LED will continuously flash and the display will turn on
the PGM descriptor to indicate that the monitor is in program mode.

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The displayed setting is changed by pressing the Up and Down
Buttons. The Up Button will increment the set point by 1 fpm or by
0.01 m/s, depending on the units configuration. The Down Button will
decrement the set point by 1 fpm or by 0.01 m/s. When the desired
setting is displayed, press the Test/Reset Button. The PGM descriptor
will flash once and the horn will give two quick beeps to acknowledge
the save and the monitor will return to normal operation and display the
current airflow reading.
IMPORTANT: If the Test/Reset button is pressed and held for 2
seconds, the change will not be saved; this is signalled via one long
horn beep
LED Status When Changing the Alarm Setpoint
Alarm LED Status
Low alarm Red LED flashes
High alarm Green LED flashes
Night setback low alarm Yellow LED flashes
High Alarm Disable
The high alarm is enabled/disabled through the Changing Alarm Set
Points procedure described above. To disable the high alarm, the high
alarm set point should be set to OFF. While scrolling through the high
alarm set point values, the OFF selection is located right after the upper
most range of the allowable values. If the high alarm is enabled, the
relay can be disabled/enabled for the high alarm by using
Configuration Parameter P11.
Emergency Purge
This button can be configured to activate a relay that can be used to
command the fume hood damper to full open until pressed again. See
Configuration Parameter P09 and P10 to set up the relay.