MSA Ultima XI User manual

Ultima®XI Infrared
Gas Monitor
Instruction Manual
THIS MANUAL MUST BE CAREFULLY READ BY ALL INDIVIDUALS WHO HAVE OR WILL
HAVE THE RESPONSIBILITY FOR USING OR SERVICING THE PRODUCT. Like any piece
of complex equipment, this device will perform as designed only if it is used and serviced
in accordance with the manufacturer’s instructions. OTHERWISE, IT COULD FAIL TO
PERFORM AS DESIGNED AND PERSONS WHO RELY ON THIS PRODUCT FOR THEIR
SAFETY COULD SUSTAIN SEVERE PERSONAL INJURY OR LOSS OF LIFE.
The warranties made by Mine Safety Appliances Company with respect to the product are
voided if the product is not used and serviced in accordance with the instructions in this
manual. Please protect yourself and others by following them. We encourage our
customers to write or call regarding this equipment prior to use or for any additional
information relative to use or service.
In the U.S., to contact your nearest stocking location, dial toll-free 1-800-MSA-INST
To contact MSA International, dial 1-412-967-3354.
© MINE SAFETY APPLIANCES COMPANY 2009 - All Rights Reserved
This manual is available on the internet at www.msanet.com.
Inquiries can also be e-mailed to customer[email protected].
Manufactured by
MSA NORTH AMERICA
P.O. Box 427, Pittsburgh, Pennsylvania 15230
(L)-Y Rev 3 10052972
"! WARNING

i
MSA Permanent Instrument Warranty
1. Warranty- Seller warrants that this product will be free from
mechanical defect or faulty workmanship for the following period:
• IR Sensor source: ten (10) years from date of shipment
• All other IR components: two (2) years from date of shipment.
This warranty is applicable provided it is maintained and used in
accordance with Seller's instructions and/ or recommendations.
This warranty does not apply to expendable or consumable parts
whose normal life expectancy is less than one (1) year. The Seller
shall be released from all obligations under this warranty in the
event repairs or modifications are made by persons other than its
own or authorized service personnel or if the warranty claim results
from physical abuse or misuse of the product. No agent, employee
or representative of the Seller has any authority to bind the Seller
to any affirmation, representation or warranty concerning the goods
sold under this contract. Seller makes no warranty concerning
components or accessories not manufactured by the Seller, but will
pass onto the Purchaser all warranties of manufacturers of such
components. THIS WARRANTY IS IN LIEU OF ALL OTHER
WARRANTIES, EXPRESSED, IMPLIED OR STATUTORY, AND IS
STRICTLY LIMITED TO THE TERMS HEREOF. SELLER
SPECIFICALLY DISCLAIMS ANY WARRANTY OF
MERCHANTABILITY OR OF FITNESS FOR A PARTICULAR
PURPOSE.
2. Exclusive Remedy- It is expressly agreed that Purchaser's sole
and exclusive remedy for breach of the above warranty, for any
tortious conduct of Seller, or for any other cause of action, shall be
the repair and/ or replacement at Seller's option, of any equipment
or parts thereof, which after examination by Seller is proven to be
defective. Replacement equipment and/ or parts will be provided at
no cost to Purchaser, F.O.B. Seller's Plant. Failure of Seller to
successfully repair any nonconforming product shall not cause the
remedy established hereby to fail of its essential purpose.
3. Exclusion of Consequential Damage- Purchaser specifically
understands and agrees that under no circumstances will seller be
liable to purchaser for economic, special, incidental or
consequential damages or losses of any kind whatsoever, including
but not limited to, loss of anticipated profits and any other loss
caused by reason of non-operation of the goods. This exclusion is
applicable to claims for breach of warranty, tortious conduct or any
other cause of action against seller.

General Warnings and Cautions
1. The Ultima XI Infrared Gas Monitors described in this manual
must be installed, operated and maintained in strict accordance
with their labels, cautions, warnings,instructions, and within the
limitations stated. Verify that the class, group, and temperature
ratings of the equipment agree with the actual classification of
the location.
2. The Ultima XI Infrared Gas Monitor is designed to detect gases
or vapors in air. It can also measure the concentration of gases or
vapors in steam or inert or oxygen-deficient atmospheres. .
3. Use only genuine MSA replacement parts when performing any
maintenance procedures provided in this manual. Failure to do so
may seriously impair instrument performance. Repair or alteration
of the Ultima XI Infrared Gas Monitor, beyond the scope of these
maintenance instructions or by anyone other than authorized MSA
service personnel, could cause the product to fail to perform as
designed.
4. The Ultima XI Infrared Gas Monitor detects the presence of most
combustible gases by identifying the difference in the amount of
infrared light energy absorbed during the presence of these gases.
This monitor, however, does NOT detect the presence of hydrogen
gas and must never be used to monitor for hydrogen gas.
5. The standard Ultima XI Infrared Gas Monitor does not detect the
presence of acetylene gas. The presence of acetylene gas will
desensitize sensor performance. Custom-built acetylene sensors
are available through your MSA representative.
6. CSA performance Certification to standard C22.2 No. 152 is valid
only when the instrument is calibrated on methane per the
instruction manual.
"WARNING
ii

1. As with all gas monitors of this type, high levels of, or long
exposure to, certain compounds in the tested atmosphere could
contaminate the sensors. In atmospheres where an Ultima XI
Infrared Gas Monitor may be exposed to such materials, calibration
must be performed frequently to ensure that operation is
dependable and display indications are accurate.
2. The Ultima XI Infrared Gas Monitor must not be painted. If painting
is done in an area where a Monitor is located, care must be
exercised to ensure that paint is not deposited on the
environmental shield of the Ultima XI Infrared Gas Monitor, if so
equipped. Such paint deposits would interfere with the diffusion
process, whereby a sample of the atmosphere being monitored
diffuses into the Monitor.
3. The only absolute method to ensure proper operation of an Ultima
XI Infrared Monitor is to check it with a known concentration of the
gas for which it has been calibrated. Consequently, calibration
checks must be included as part of the routine inspection of the
system.
4. Protect the Ultima XI Infrared Gas Monitor from extreme vibration.
FAILURE TO FOLLOW THE ABOVE CAN RESULT IN PRODUCT
DAMAGE AND/OR AN UNSAFE CONDITION.
"CAUTION
iii

Table of Contents
Chapter 1,
Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-1
General Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-1
Identifying Your Unit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-1
Installing Your Gas Monitor . . . . . . . . . . . . . . . . . . . . . . . . . . .1-2
Ultima XI Electrical Connections . . . . . . . . . . . . . . . . . . . . . . .1-4
For Milliamp Output . . . . . . . . . . . . . . . . . . . . . . . . . . .1-5
Chapter 2,
Start-up and Calibration . . . . . . . . . . . . . . . . . . .2-1
Calibration Basics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-1
Ultima XI Calibration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-2
Calibration Kit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-5
Chapter 3,
Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-1
Chapter 4,
Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4-1
General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4-1
Ultima XI Cleaning Procedure . . . . . . . . . . . . . . . . . . . . . . . . .4-1
Appendix A,
Calibration Guide
for Additional XI Gases . . . . . . . . . . . . . . . . . . . .A-1
iv

List of Figures
Figure 1-1. Explosion-Proof Ultima XI Infrared Gas Monitor .1-1
Figure 1-2. Explosion-Proof Ultima XI Infrared Gas Monitor
with Junction Box . . . . . . . . . . . . . . . . . . . . . . . . .1-2
Figure 1-3. Ultima XI Infrared Gas Monitor . . . . . . . . . . . . . . .1-3
Figure 1-4. Ultima XI Installation Requirements . . . . . . . . . . .1-4
Figure 1-5. Ultima XI Infrared Gas Monitor
with Junction Box . . . . . . . . . . . . . . . . . . . . . . . . .1-5
Figure 2-1. Intrinsically Safe Ultima XI Calibration Cap . . . . .2-3
Figure 2-2. Calibration Sequence Diagram . . . . . . . . . . . . . . .2-3
Figure 2-3. Environmental Guard . . . . . . . . . . . . . . . . . . . . . .2-4
List of Tables
Table 1-1. Ultima XI Maximum Cable Length
& 4-20 mA Signal Load . . . . . . . . . . . . . . . . . . . .1-5
Table 2-1. Instrument Operation . . . . . . . . . . . . . . . . . . . . . . .2-1
Table 2-2. Calibration Kit Table . . . . . . . . . . . . . . . . . . . . . . .2-5
Table 3-1 . Performance Specifications . . . . . . . . . . . . . . . . .3-1
Table 3-2. Certification and Approval . . . . . . . . . . . . . . . . . . .3-2
Table 3-3. Installation Drawings . . . . . . . . . . . . . . . . . . . . . . .3-2
Table 4-1. Parts List . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4-3
v

1-1
Chapter 1,
Installation
General Description
The Ultima XI Infrared Gas Monitor is designed to sample the
environment where mounted and alert you to potentially dangerous
levels of combustible gas. The Ultima XI Infrared Gas Monitor is
shipped factory-calibrated and is labeled with target gas, calibration gas
and span setting information. The target gas is not field-configurable
and cannot be changed. The Ultima XI Gas Monitor is a stand-alone
unit with a 4 to 20 mA output.
Identifying Your Unit
• The Ultima XI Infrared Gas Monitor is housed in a 316 stainless
steel explosion-proof enclosure (FIGURE 1-1).
Do not mix units with different area classifications. All units
Figure 1-1. Explosion-Proof Ultima XI Infrared Gas Monitor

• The Ultima XI Infrared Gas Monitor is also available with an
optional junction box equipped with a terminal strip for easy wiring
(FIGURE 1-2).
Do not mix units with different area classifications. All units
Installing Your Gas Monitor
Generally, the Ultima XI Gas Monitor should be mounted close to the
area where a leak is likely to occur or where the gas is expected.
Testing for ventilation patterns may be helpful in establishing locations
for the Ultima XI Gas Monitor in enclosed areas. Smoke tubes
(P/N 458481) are useful in measuring these patterns to help determine
where gases may flow or accumulate.
Mount the Ultima XI Gas Monitor on a support by using suitable
hardware (not supplied), and attach rigid conduit and a conduit seal
fitting (for XP installations). The optional condulet assembly can also be
used for wiring power and signal.
NOTE: The XI Gas sensor must be mounted with the sensor
extended horizontally as shown in FIGURE 1-2.
The Ultima XI Infrared Gas Monitor contains no user- or field-
serviceable parts and must be returned to the factory for
repair. Any attempt to open the monitor will damage the unit
and void the warranty.
Mount the Ultima XI Infrared Gas Monitor with the sensor
inlet fitting extended horizontally from the main enclosure
(FIGURES 1-1 and 1-2). Horizontal mounting will help pre-
vent the build-up of particulate or liquid matter on the moni-
tor's optical surfaces.
"CAUTION
"WARNING
Figure 1-2. Explosion-Proof Ultima XI Infrared Gas Monitor
with Junction Box
1-2

Do not paint the Ultima XI Infrared Gas Monitor. If painting is
done in an area where a sensor is located, exercise caution
to ensure paint is not deposited on the sensor inlet fitting.
Such paint deposits would interfere with the diffusion
process, whereby a sample of the monitored atmosphere
diffuses into the sensor. In addition, solvents in the paint
may cause an alarm condition to occur.
Protect the Ultima XI Infrared Gas Monitor from extreme
vibration. Do not mount sensing head in direct sunlight as
this may cause the sensor to overheat.
During sensor installation or removal, do not use any tools
or apply excessive force to the two legs that support the
unit's reflectors (FIGURE 1-3). Applying force to the legs can
permanently damage the monitor.
The monitor's environmental guard should be installed on
the unit at all times. If the monitor is to be operated without
the guard, frequent checks should be made to ensure par-
ticulate or liquid matter has not collected on the windows.
Use a wrench on the hex nut in the sensor neck to install or
remove the sensor.
Do not mix units with different area classifications. All units
Figure 1-3. Ultima XI Infrared Gas Monitor
1-3

Ultima XI Electrical Connections
The Ultima XI Gas Monitor is provided with input wires for power and
signal connections. An optional condulet assembly is also available.
An external power supply is required.
• For power requirements, see Chapter 3, "Specifications".
• All connections should be made by following appropriate wire code
procedures.
NOTE: Refer to TABLE 3-3 for appropriate installation drawing.
Before wiring the Ultima XI Infrared Gas Monitor, disconnect
or isolate all power connected to the monitor; otherwise,
electrical shock could occur.
Be sure to install your Ultima XI Infrared Gas Monitor in
accordance with National and local Wiring Regulations.
Failure to do so can result in an unsafe condition.
The Ultima XI Monitor is a three-wire transmitter that operates in the
current source mode and can be wired directly to the input wires
(FIGURE 1-4) or with the optional junction box (FIGURE 1-5). TABLE
1-1 provides typical cable lengths and wire sizes for installation.
"WARNING
Figure 1-4. Ultima XI Installation Requirements
1-4

Do not mix units with different area classifications. All units
Table 1-1. Ultima XI Maximum Cable Length & 4-20 mA Signal Load
POWER SUPPLY 24 VOLTS 12 VOLTS
18 AWG CABLE 2,000 feet 300 feet
16 AWG CABLE 3,500 feet 500 feet
12 AWG CABLE 5,000 feet 900 feet
4 - 20 mA SIGNAL MAXIMUM LOAD 600 OHMS 300 OHMS
• In all installations, twisted-pair, instrument quality cable is
recommended. Shielded cable is recommended for cable runs
where radio frequency interference (RFI), electromagnetic
interference (EMl), or other noise sources exist (such as motors,
welding equipment, heaters, etc.).
• Conduit may also be needed in areas where a large amount of
electrical noise is expected.
Proper installation should ensure that water and dirt are not able to
enter the unit via the wire or conduit.
For Milliamp Output
The Ultima XI Infrared Gas Monitor may be connected to any device
capable of accepting a 4 to 20 mA analog signal, such as:
• SUPREMA (with 4 to 20 mA input modules)
• 9010/9020 Controller
• Gasgard®Family of Controllers
• DCS’s, etc.
Figure 1-5. Ultima XI Infrared Gas Monitor with Junction Box
1-5

Chapter 2,
Start-up and Calibration
The Ultima XI Infrared Gas Monitor is factory-calibrated and ready for
immediate use. The Ultima XI Gas Monitor provides a 4 to 20 mA output
signal that can be used in conjunction with data acquisition controllers.
During instrument operation, the 4 to 20 mA output signal provides the
information shown in TABLE 2-1.
Table 2-1. Instrument Operation
OPERATION 4 to 20 mA
NORMAL, NO ALARMS Gas value
ALARMING Gas value
FAULT 3.0 mA
POWER UP/ COUNTDOWN 3.75 mA (approximately 65 seconds)
SENSOR CAL 3.75 mA
CAL FAULT Gas value
UNDER-RANGE 3.0 mA if gas value 0 or less; gas value otherwise
OVER-RANGE 21.0 mA
Calibration Basics
• While the Ultima XI Infrared Gas Monitor is factory-calibrated, it is
good practice to calibrate the unit once it is installed in its final
environmental destination.
• As with any type of gas monitor, the only true check of its
performance is to apply gas directly to the sensor. The frequency
of the calibration gas tests depends on the operating time and
chemical exposures of the sensors. New sensors should be
calibrated more often until the calibration records prove sensor
stability. The calibration frequency can then be reduced to the
schedule set by the safety officer or plant manager.
• Before calibrating, the Ultima XI Infrared Gas Monitor must be
powered for a minimum of one hour to allow the sensor to settle
into its new environment.
• Output signal during calibration is 3.75 mA.
2-1

• Read all calibration instructions before attempting an actual
calibration.
• Identify and become familiar with all of the calibration components.
• During the calibration, it may be necessary to quickly apply the
span gas to the unit. Prior connection of the calibration
components will aid in the ease of unit calibration.
• The only true check of any gas monitor's performance is to apply
gas directly to the sensor.
• The calibration procedure must be performed regularly.
Before attempting a calibration, power the monitor for at
least one full hour. To ensure a fully functional sensor, per-
form a calibration check and adjustments at initial start-up
and at regular intervals.
Ultima XI Calibration
• Although a full calibration (zero and span) can be performed on the
Ultima XI Infrared Gas Monitor, a no-gas (zero) calibration is
sufficient to properly calibrate the monitor.
• Normally, any degradation of the sensor's performance is
associated with slight drifts in its zero response that, in turn, will
adversely affect its span performance. Restoring the sensor's zero
is typically sufficient to restore its span performance.
• The following steps are required to perform an Ultima XI
calibration.
• The calibration sequence diagram is shown in FIGURE 2-2.
1. Remove the environmental guard or flow cap from the Ultima XI
Gas Monitor (FIGURE 2-3).
2. Turn the switch on the calibration cap to the ON position.
3. Connect the Ultima XI Calibration Cap (FIGURE 2-1) to the Ultima
XI Gas Monitor.
• The Calibration Cap display flashes "-", indicating the cap is
interfacing with the Ultima XI Gas Monitor.
• The Calibration Cap display flashes "C", indicating the unit is in
zero calibration mode.
"CAUTION
2-2

Apply zero gas to the calibration port. Zero gas can be supplied as
ambient air or from the zero gas cylinder in the calibration kit as
noted in TABLE 2-2.
Do not mix units with different area classifications. All units
Do not mix units with different area classifications. All units
Figure 2-2. Calibration Sequence Diagram
Figure 2-1. Intrinsically Safe Ultima XI Calibration Cap
2-3

• If the user can confirm that the ambient air is free of detectable
analyte gas, it can be used in place of the zero gas cylinder.
• After approximately 60 seconds, the Calibration Cap display
indicates "P" for pass or "F" for fail.
4. After successful completion of the zero calibration and, if only a
zero calibration is being performed, a span check should be
performed to ensure proper operation. If the span check does not
yield accurate results, perform a full calibration (zero and span).
5. After successful completion of the zero calibration, a span
calibration can be performed by applying span gas through the
Calibration Cap port (see TABLE 2-2 for span gas selection).
• The unit must see gas within 30 seconds after successful
completion of the zero calibration in order for the span
calibration to initiate.
• Initiating a span procedure causes the display to flash “S”.
• After approximately 60 seconds, the Calibration Cap display
indicates "P" for pass or "F" for fail.
6. When calibration is complete, remove the Calibration Cap and
connect the environmental guard or flow cap. The 4- 20 mA is held
at 4 mA for two minutes to reduce the chance of a nuisance alarm
upon completion of a calibration procedure.
7. Apply cap to next sensor to be calibrated. Turn switch to OFF
position if the calibration cap will not be used for extended period
to prolong battery capacity.
NOTE: When a zero or span calibration failure occurs, the Ultima
XI Gas Monitor reverts back to its last successful
calibration settings.
Figure 2-3. Environmental Guard
2-4

NOTE: If the Ultima XI Calibration Cap is left on for more than
fifteen minutes after calibration concludes, the 4 to 20 mA
signal indicates a fault status.
The Calibration Cap must be removed from the XI sensor
after completing the Zeroing and/or Spanning procedure;
otherwise, the sensor cannot perform properly.
Calibration Kit
Calibration Kits are available for the Ultima XI Infrared Gas Monitor in
the event zero or span gas is required. The recommended calibration
kits are shown in TABLE 2-2.
Table 2-2. Calibration Kit Table
GAS TYPE CAL CYLINDER SPAN
CYLINDER P/N VALUE CAL KIT
Methane 2.5% Methane 10028032 50% LEL 40
Propane 0.6% Propane 10028034 29% LEL 40
Ethane 0.6% Propane 10028034 25% LEL 40
Butane 0.6% Propane 10028034 28% LEL 40
Pentane 0.6% Propane 10028034 33% LEL 40
Hexane 0.6% Propane 10028034 41% LEL 40
Cyclopentane 0.6% Propane 10028034 30% LEL 40
Ethylene 0.1% Propane 711054 28% LEL 40
Zero Gas 100% Nitrogen 10028030 0% LEL 40
See Appendix A for additional XI calibration gases.
"WARNING
2-5

Chapter 3,
Specifications
Table 3-1 . Performance Specifications
TEMPERATURE
RANGE -40 to +60°C (-40 to +149°F)
DRIFT ZERO DRIFT Less than 5% per year, typically
SPAN DRIFT Less than 10% per year, typically
NOISE Less than 1% FS
ACCURACY IR COMBUSTIBLE
GAS: METHANE,
PROPANE <50% LEL: ±2% FS
>50%LEL ±5% FS: ±2% FS
STEP CHANGE
RESPONSE TIME TO REACH
50% OF SCALE
COMBUSTIBLES Less than 10 seconds
TIME TO REACH
90% OF SCALE
COMBUSTIBLES Less than 30 seconds
HUMIDITY 15 to 95% RH,
non-condensing,
24 hours or less
35 to 95% RH, long term
SENSOR LIFE FULL
REPLACEMENT
WARRANTY 10 years for IR sensor source
(See "MSA Instrument Warranty" in this manual
for complete details)
WIRING
REQUIREMENTS Three-wire
POWER INPUT 7-30 VDC
SIGNAL
OUTPUT 4-20 mA Three-wire current source
ULTIMA XI
PHYSICAL SIZE 2-1/2 x 8" (64 x 203 mm)
WEIGHT 6.6 lbs. (3 Kg.)
3-1

Table 3-2. Certification and Approval
FMus Class I, Div. 1, Groups A, B, C and D
cFM Class I, Div. 1, Groups B, C and D
ULus Enclosure: Class I, Div. 1, Groups A, B, C and D;
Class II, Groups E, F and G.
cUL Enclosure: Class I, Div. 1, Groups B, C and D; Class II,
Groups E, F and G.
CSA Class I, Div. 1, Groups B, C and D
Dekra Exam II 2G EEx d IIC T5
CE Low Voltage Directive, EMC Directive, ATEX
Approval subject to change without notice. Check label for
specific approval information.
Table 3-3. Installation Drawings
INSTALLATION
OUTLINE DRAWINGS DOCUMENT NO.
UL 10000018418
3-2

Chapter 4,
Maintenance
General
The Ultima XI Infrared Gas Monitor is:
• not field-serviceable and must be returned to the factory for repair.
• constantly performing a self-check.
When a critical error is detected in the unit, the 4 to 20 mA output
signal goes to the 3.0 mA fault condition.
Ultima XI Cleaning Procedure
The presence of particulate matter, oil films, liquid water, or the residue
from water drops on the two monitor windows can adversely affect its
performance. The environmental guard is designed to prevent foreign
solids or liquids from reaching the monitor's optical system. Additionally,
heating elements are incorporated into the unit to prevent water
condensation. Under severe conditions, however, some material may
collect on these surfaces and it may be necessary to occasionally check
and clean the windows.
1. Remove the environmental or flow cap.
2. Place an opaque object (piece of paper, end of wrench handle,
etc.) between the light source window and the mirror to completely
obscure the light path for two to three seconds.
• The Ultima XIR/Ultima XI Monitor enters the Cleaning Mode
for two minutes.
NOTE: While in the Cleaning Mode, the sensor will not
respond to the presence of gas.
• The analog current output is 3.0 mA during this time.
• The display indicates 'low signal'’.
4-1

3. While both windows are made of a highly durable material that is
not easily scratched, avoid excessive pressure when cleaning
them. Clean, cotton-tipped applicators are the most convenient tool
to remove material collected on the windows.
• Use a dry applicator or one moistened with distilled water to
wipe the window and remove dust.
• Use an additional clean, dry applicator to remove any residual
water.
• Use an applicator moistened with isopropyl alcohol to remove
heavy deposits of solids, liquids or oil films. Clean the window
again with a second applicator moistened with distilled water;
then, dry the window with a final applicator.
• Avoid using excessive amounts of water or alcohol in the
cleaning procedure, and inspect the window to ensure that the
entire surface is clean.
• The unit remains in the Cleaning Mode for a minimum of
two minutes. If active cleaning is still in progress at the end
of this period, the sensor detects the motion of this object
in its light path and automatically extends the Cleaning
Mode for 15 seconds. Further 15-second Cleaning Mode
extensions continue until no motion is detected.
NOTE: When the cleaning process is complete, be sure to
remove all objects from the light path.
4. When exiting the Cleaning Mode, the unit returns to normal
operation. If water or isopropyl alcohol was used, allow
the unit to operate for 15 minutes to completely dry before
replacing the environmental guard and continuing to monitor
for combustible gas.
5. Replace the environmental or flow cap.
6. After cleaning the windows, it is advisable to check the sensor’s
response to both zero and calibration gas.
4-2