RKI Instruments 65-2445 Series User manual

RKI Instruments, Inc.
www.rkiinstruments.com
65-2445-XX
PPM Hydrogen Transmitter
Operator’s Manual
Part Number: 71-0609
Revision: 0
Released: 5/8/23

2• 65-2445-XX PPM Hydrogen Transmitter Operator’s Manual
WARNING
Read and understand this instruction manual before operating
instrument. Improper use of the gas monitor could result in bodily
harm or death.
Periodic calibration and maintenance of the gas monitor is essential
for proper operation and correct readings. Please calibrate and
maintain this instrument regularly! Frequency of calibration depends
upon the type of use you have and the sensor types. For most
applications, typical calibration frequencies are between 3 and 6
months but can be more often or less often based on your usage.

65-2445-XX PPM Hydrogen Transmitter Operator’s Manual • 3
Product Warranty
RKI Instruments, Inc. warrants gas alarm equipment sold by us to be free from defects in
materials, workmanship, and performance for a period of one year* from the date of shipment
from RKI Instruments, Inc. Any parts found defective within that period will be repaired or
replaced, at our option, free of charge. Parts must be returned to RKI Instruments, Inc. for repair
or replacement. This warranty does not apply to those items which by their nature are subject to
deterioration or consumption in normal service, and which must be cleaned, repaired or replaced
on a routine basis. Examples of such items are:
• Pump diaphragms and valves
•Fuses
•Batteries
• Filter elements
Warranty is voided by abuse including mechanical damage, alteration, rough handling, or repair
procedures not in accordance with instruction manual. This warranty indicates the full extend of
our liability, and we are not responsible for removal or replacement costs, local repair costs,
transportation costs, or contingent expenses incurred without our prior approval.
THIS WARRANTY IS EXPRESSLY IN LIEU OF ANY AND ALL OTHER WARRANTIES AND
REPRESENTATIONS, EXPRESSED OR IMPLIED, AND ALL OTHER OBLIGATIONS OR
LIABILITIES ON THE PART OF RKI INSTRUMENTS, INC. INCLUDING BUT NOT LIMITED TO,
THE WARRANTY OF MERCHANTABILITY OR FITNESS FOR APARTI CULAR PURPOSE. INNO
EVENT SHALL RKI INSTRUMENTS, INC. BE LIABLE FOR INDIRECT, INCIDENTAL, OR
CONSEQUENTIAL LOSS OR DAMAGE OF ANY KIND CONNECTED WITH THE USE OF ITS
PRODUCTS OR FAILURE OF ITS PRODUCTS TO FUNCTION OR OPERATE PROPERLY.
This warranty covers instruments and parts sold to users only by authorized distributors, dealers
and representatives as appointed by RKI Instruments, Inc.
We do not assume indemnification for any accident or damage caused by the operation of this gas
monitor and our warranty is limited to the replacement of parts or our complete goods. Warranty
covers parts and labor performed at RKI Instruments, Inc. only, and does not cover field labor or
shipment of parts back to RKI.

4• 65-2445-XX PPM Hydrogen Transmitter Operator’s Manual
Table of Contents
Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
PPM Hydrogen Detector. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Amplifier. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Junction Box . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Mounting the PPM Hydrogen Transmitter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Wiring the PPM Hydrogen Transmitter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Startup. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Introducing Incoming Power . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Transmitter Burn-In Period. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Setting the Zero Signal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Preventive Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Replacing Components of the PPM Hydrogen Transmitter . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Calibration Frequency . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Calibration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Calibration Kit Humidifier Tube. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Preparing for Calibration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
Setting the Zero Reading . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
Setting the Span Reading . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
Setting the Linearization. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
Returning to Normal Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
Parts List . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

65-2445-XX PPM Hydrogen Transmitter Overview • 5
Overview
This manual describes the 65-2445-XX ppm hydrogen transmitter. This manual also describes
how to install, start up, configure, maintain, and calibrate the transmitter when it is used with a
gas monitoring controller. A parts list at the end of this manual lists replacement parts and
accessories for the transmitter.
Specifications
Table 1 lists specifications for the ppm hydrogen transmitter.
WARNING: When using the 65-2445-XX, you must follow the instructions and warnings in
this manual to assure proper and safe operation of the 65-2445-XX and to
minimize the risk of personal injury. Be sure to maintain and periodically
calibrate the 65-2445-XX as described in this manual.
Table 1: Specifications
Target Gas Hydrogen (H2)
Detection Range • 65-2445-100: 0 - 100 ppm
• 65-2445-500: 0 - 500 ppm
• 65-2445-1000: 0 - 1,000 ppm
• 65-2445-2000: 0 - 2,000 ppm
Area Classification Explosion-proof for Class I, Groups B, C, and D
Sampling Method Diffusion
Input Power 10 - 30 VDC
Signal Output 4 to 20 mA with impedance maximums listed
below:
• 12 VDC input: 500 Ohms
• 24 VDC input: 1000 Ohms
Response Time 90% in 45 seconds

6• Description 65-2445-XX PPM Hydrogen Transmitter
Description
This section describes the ppm hydrogen transmitter’s components. It is a 4 to 20 mA type
detector head. It consists of the ppm hydrogen detector, amplifier, and junction box.
Figure 1: Component Location
Amplifier
J-Box
Hydrogen Detector
LINEAR
Reducing Bushing,
3/4 NPT to 1/2 NPT
COARSE
FIN E
DETECTOR PWR / SIG
SW B R

65-2445-XX PPM Hydrogen Transmitter Description • 7
PPM Hydrogen Detector
The ppm hydrogen detector is a MOS type (metal oxide semiconductor) detector packaged in
a 1/2 NPT nipple with a sintered metal flame arrestor on one end allowing ambient air to diffuse
into the detector. The flame arrestor also contains any sparks which may occur within the detector.
The 1/2 NPT mounting threads at the top of the detector allow you to mount it into the bottom
conduit hub of the junction box. A rainshield screws onto the bottom of the detector (flame
arrestor end). The rainshield helps protect the detector from rain and debris in the monitoring
environment. Three color-coded leads extend from the top of the detector. The leads allow you to
connect the detector to the amplifier.
The detector has a built in molecular sieve that only allows hydrogen to diffuse into the detector.
The output of the detector is non-linear and is linearized by the amplifier (see below).
Amplifier
The amplifier converts the non-linear electrical output from the detector to a linear 4 to 20 mA
signal that corresponds to the detection range and transmits the signal to a gas monitoring
controller. The amplifier includes the terminal strips, coarse span pot, fine span pot, linearizing
pot, and test points.
Figure 2: Amplifier Component Location
Controller Terminal Strip
The controller terminal strip is a three position plug-in style terminal strip located near the top of
the amplifier. Use the controller terminal strip to wire the transmitter to a controller.
Mounting Screw
w/ flat and lock washer
-TestPoint,Black
DETECTOR
WBR
+ Test Point, Red
Detector Terminal Strip
Controller Terminal Strip
COARSE
PWR/ SIG
S
FINE
Coarse
Span Pot
Linearizing Pot
Fine Span
Pot
LINEAR

8• Description 65-2445-XX PPM Hydrogen Transmitter
Detector Terminal Strip
The detector terminal strip is a three position plug-in style terminal strip located below the
controller terminal strip. Use the detector terminal strip to connect the detector to the amplifier.
NOTE: The detector is factory-wired to the detector terminal strip. See page 10 for all wiring
procedures related to the transmitter.
Coarse Span Pot
The coarse span pot (labeled COARSE) is located to the left of the detector terminal strip and
below the fine span pot (see Figure 2). Use a small flat blade screwdriver to turn the span pot’s
adjustment screw and adjust the amplifier’s coarse full scale response output during the
calibration procedure.
Fine Span Pot
The fine span pot (labeled FINE) is located to the left of the detector terminal strip and above the
coarse span pot (see Figure 2). Use a small flat blade screwdriver to turn the span pot’s adjustment
screw and adjust the amplifier’s fine full scale response output during the calibration procedure.
Linearizing Pot
The linearizing pot (labeled LINEAR) is located in the bottom left corner of the amplifier (see
Figure 2). Use a small flat blade screwdriver to turn the linearizing pot’s adjustment screw while
applying mid-scale gas to linearize the transmitter’s output during the calibration procedure.
Test Points
The test points are on the right side of the amplifier (see Figure 2). The test points produce a 100
to 500 mV output that corresponds to the transmitter’s 4 to 20 mA output. Use the test points and
a voltmeter to measure the amplifier’s output during the start-up and calibration procedures. The
black test point on the bottom is the negative (-) test point and the red test point on the top is the
positive (+) test point.
Junction Box
Use the junction box to install the transmitter at a mounting site that is remote from the controller.
The junction box also protects the amplifier and wiring connections made to the amplifier. Use the
top 3/4 NPT conduit hub to connect wiring from the amplifier to the controller. Use the cover on
the front of the junction box to access the interior of the junction box. The detector and amplifier
are factory installed in the junction box.

65-2445-XX PPM Hydrogen Transmitter Installation • 9
Installation
This section describes procedures to mount the ppm hydrogen transmitter in the monitoring
environment and wire the transmitter to a controller.
Mounting the PPM Hydrogen Transmitter
Figure 3: Mounting the PPM Hydrogen Transmitter
1. Select a mounting site that is representative of the monitoring environment. Consider the
following when you select the mounting site.
• Select a site where the transmitter is not likely to be bumped or disturbed. Make sure there
is sufficient room to perform start-up, maintenance, and calibration procedures.
• Select a site where the target gas is likely to be found first. For hydrogen, which is lighter
than air, mount the transmitter near the ceiling or where hydrogen is most likely to
accumulate.
2. At the monitoring site you select, hang or mount the junction box with the detector facing
down (see Figure 3).
.38
.75
2.70
JBox
Rubber
Spacers,
3X
3/4 NPT Female
3.65
Hydrogen
Detector
3/4 x 1/2 Reducing
Bushing
7.5 max

10 • Installation 65-2445-XX PPM Hydrogen Transmitter
Wiring the PPM Hydrogen Transmitter
WARNING: Always verify that the power to the controller is off before you make wiring
connections.
1. Turn off power to the controller.
2. Place the controller’s power switch in the OFF position.
3. Remove the junction box cover.
4. The detector leads are factory wired. Verify that the detector leads are wired to the amplifier’s
detector terminal strip as shown in Figure 4.
5. To gain access to a plug-in terminal strip for wiring, pull it out of its socket by grasping the
terminal strip and pulling. The detector strip is keyed so that the controller and detector
terminal strips cannot be reversed inadvertently.
6. Guide a three-conductor, shielded cable or three wires in conduit through the top conduit hub
of the junction box.
7. Pull out the controller terminal strip, and connect the three wires to the terminal strip as
follows (see Figure 4).
• Connect the positive wire to the PWR/SIG “+” terminal.
• Connect the signal wire to the PWR/SIG “S” terminal.
• Connect the negative wire to the PWR/SIG “-” terminal.
CAUTION: If shielded cable is used, leave the cable shield’s drain wire
disconnected and insulated at the transmitter. You will connect the
opposite end of the cable’s drain wire to the controller’s chassis (earth)
ground.
8. Reinstall the controller terminal strip into its socket.
9. Secure the junction box cover to the junction box.
10. Route the cable or wires leading from the ppm hydrogen transmitter through one of the
conduit hubs at the controller housing.
CAUTION: Do not route power and transmitter wiring through the same controller
conduit hub. The power cable may disrupt the transmission of the
transmitter signal to the controller.

65-2445-XX PPM Hydrogen Transmitter Installation • 11
11. Connect the wires to the applicable detector/transmitter terminal strip at the controller as
shown in Figure 4.
Figure 4: Wiring the PPM Hydrogen Transmitter to a Controller
12. If shielded cable is used, connect the cable’s drain wire to an available chassis (earth) ground
at the controller. RKI controllers typically have a ground stud that can be used to ground the
cable’s drain wire.
Cable Shield
Red
Black Detector Wires
Fine Span
Pot
Controller
- (DC Ground)
+24VDC
4-20mAIn(S)
PWR /SIG
SR
FINE
COARSE
BW
Coarse
Span Pot White
LINEAR
DETECTOR

12 • Start Up 65-2445-XX PPM Hydrogen Transmitter
Start Up
This section describes procedures to start up the ppm hydrogen transmitter and place the
transmitter into normal operation.
Introducing Incoming Power
1. Complete the installation procedures described earlier in this manual.
2. Verify that the power wiring to the controller is correct and secure. Refer to the controller
operator’s manual.
NOTE: When a transmitter is first powered up after installation or being off power
for an extended period, its output may be high enough to cause an alarm or
low enough to indicate a failure for a brief period before stabilizing within a
few minutes. Be sure to make arrangements so that this does not cause
unwanted alarms.
3. Turn on power to the controller.
4. Turn on the controller.
5. Verify that the controller is on and operating properly. Refer to the controller operator’s
manual.
Transmitter Burn-In Period
Once power has been applied to the transmitter, it will take 4-6 weeks for the transmitter signal to
the controller to stabilize completely. This is the burn-in period. The zero reading should settle
down close to zero within 2-3 hours of applying power. The transmitter is calibrated at the factory
before shipment and it is not necessary to calibrate the transmitter after installation until the
recommended calibration frequency interval has passed. If calibration of the transmitter is desired
after installation but before the recommended calibration frequency interval passes, wait at least 4
weeks after startup before calibrating the transmitter. A burn-in period of 6 weeks is
recommended. See page 17 for calibration instructions.
Setting the Zero Signal
The detector’s zero setting is controlled by electronics and is not user-adjustable.

65-2445-XX PPM Hydrogen Transmitter Maintenance • 13
Maintenance
This section describes maintenance procedures. It includes preventive maintenance,
troubleshooting, and component replacement procedures.
Preventive Maintenance
This section describes a preventive maintenance schedule to ensure the optimum performance of
the ppm hydrogen transmitter. It includes daily and quarterly procedures.
Daily
Verify a display reading of 0 ppm at the controller. Investigate significant changes in the display
reading.
Biannual
Calibrate the ppm hydrogen transmitter as described on page 17.
Troubleshooting
The troubleshooting guide describes symptoms, probable causes, and recommended action for
problems you may encounter with the ppm hydrogen transmitter.
NOTE: This troubleshooting guide describes transmitter problems only. See the controller
operator’s manual for problems you may encounter with the controller.
Table 2: Troubleshooting the ppm Hydrogen Transmitter
Condition Symptom(s) Probable Causes Recommended Action
Fail
Condition
• Controller indicates a
fail condition.
• The transmitter
wiring is
disconnected or
misconnected.
• The transmitter is
malfunctioning.
1. Verify that the transmitter
wiring is correct and secure.
2. Calibrate the transmitter.
3. If the fail condition continues,
replace the detector.
4. If the fail condition continues,
contact RKI for further
instruction.

14 • Maintenance 65-2445-XX PPM Hydrogen Transmitter
Replacing Components of the PPM Hydrogen
Transmitter
This section includes procedures to replace the ppm hydrogen detector and amplifier.
Replacing the PPM Hydrogen Detector
1. Turn off power to the controller.
2. Place the controller’s on/off switch in the OFF position.
3. Remove the junction box cover.
4. Remove the detector terminal strip from its socket.
5. Disconnect the detector leads from the detector terminal strip. Note the position of the color-
coded leads as you remove them.
6. Unscrew the detector from the junction box.
7. Guide the detector leads of the replacement detector through the bottom conduit hub of the
junction box, then screw the mounting threads of the detector into the conduit hub.
Slow or No
Response/
Difficult or
Unable to
Calibrate
• Unable to accurately
set the span or
linearizing response
during calibration.
• Transmitter requires
frequent calibration.
NOTE: Under
“normal”
circumstances, the
transmitter requires
calibration once every
6 months.
Some applications may
require a more frequent
calibration schedule.
• The calibration
cylinder is low,
out-dated, or
defective.
• The calibration gas
flow rate is too
low.
• The transmitter is
malfunctioning.
1. Verify that the calibration
cylinder contains an adequate
supply of gas.
2. Verify that the regulator used
for calibration is a 0.5 LPM
regulator.
3. If the calibration/response
difficulties continue, replace the
detector.
4. If the calibration/response
difficulties continue, contact
RKI for further instruction.
Table 2: Troubleshooting the ppm Hydrogen Transmitter (Continued)
Condition Symptom(s) Probable Causes Recommended Action

65-2445-XX PPM Hydrogen Transmitter Maintenance • 15
8. Connect the detector leads to the detector terminal strip as shown in Table 3 below and
Figure 4 on page 11 of this manual.
9. Re-install the detector terminal strip into its socket.
NOTE: When a transmitter is first powered up with a new detector, its output may be
high enough to cause an alarm or low enough to indicate a failure for a brief
period before stabilizing within a few minutes. Be sure to make
arrangements so that this does not cause unwanted alarms.
10. Turn on power to the controller.
11. Turn on the controller and place it into normal operation.
12. Allow the transmitter to run for 3 hours.
13. Perform a preliminary calibration as described on page 17. This will be a temporary
calibration since the new ppm detector must burn-in before it can be properly calibrated.
14. Allow the replacement detector to burn-in for at least 4 weeks before you continue with the
next step. A burn-in period of 6 weeks is recommended.
15. After the burn-in period, calibrate the transmitter as described on page 17.
Replacing the Amplifier
When replacing the amplifier, try to minimize the amount of time that the sensor is off power. If
the sensor is off power for more than 1 hour, it will need to burn in again.
1. Turn off power to the controller.
2. Place the controller’s on/off switch in the OFF position.
3. Remove the junction box cover.
4. Unplug the detector terminal strip and controller terminal strip from their sockets. You may
leave the wires connected to the terminal strips.
5. Unscrew and remove the screw with the flat and lock washers that secures the amplifier to the
junction box.
6. Remove the old amplifier.
Table 3: Reconnecting the PPM Detector to the Amplifier
Detector Lead Detector Terminal Strip
Red R
White W
Black B

16 • Maintenance 65-2445-XX PPM Hydrogen Transmitter
7. Install the detector and controller terminal strips into their sockets on the new amplifier as
shown in Figure 4 on page 11 of this manual. If controller leads or detector leads were
removed during this procedure, refer to Tables 4 and 5 below.
8. Install the amplifier into the junction box with the screw, lock washer, and flat washer you
removed in Step 5 above. A foam gasket that orients the amplifier and keeps it from rotating is
installed on the bottom of the amplifier. Make sure the amplifier is seated flat in the junction
box.
NOTE: When a transmitter is first powered up with a new amplifier, the initial
output may be either high or below zero. Be sure to make arrangements so
that this does not cause unwanted alarms.
9. Turn on power to the controller.
10. Turn on the controller and place it into normal operation.
11. Allow the transmitter to run overnight.
12. Perform a calibration as described on page 17.
If the sensor was off power for more than 1 hour during amplifier replacement, perform a
preliminary calibration after the new amplifier/sensor combination has run overnight.
Perform another calibration 4-6 weeks after replacement.
Table 4: Reconnecting the PPM Hydrogen Amplifier to the Controller
Amplifier’s Controller
Terminal Strip
Controller’s Transmitter
Terminal Strip (typical)
--(DC-)
S S (4 - 20 mA In)
++24V
Table 5: Reconnecting the PPM Hydrogen Detector to the Amplifier
Detector Lead Amplifier’s Detector
Terminal Strip
Red R
White W
Black B

65-2445-XX PPM Hydrogen Transmitter Calibration Frequency • 17
Calibration Frequency
Although there is no particular calibration frequency that is correct for all ppm hydrogen
transmitter applications, a calibration frequency of every 6 to 12 months is adequate for most
applications. Unless experience in a particular application dictates otherwise, RKI Instruments,
Inc. recommends a calibration frequency of every 6 months.
If an application is not very demanding, for example detection in a clean, temperature controlled
environment where hydrogen is not normally present, and calibration adjustments are minimal at
calibration, then a calibration frequency of every 12 months is adequate.
If an application is very demanding, for example if hydrogen is present often and in significant
concentrations or the environment is not well controlled, then more frequent calibration than
every 6 months may be necessary.
Calibration
This section describes how to calibrate the ppm hydrogen transmitter. It includes procedures to
prepare for calibration, set the span reading, set the linearization, and return to normal operation.
If the transmitter has been recently installed, do not adjust the factory setting on the Fine, Coarse,
or Linear pots until the transmitter has been on power for 4-6 weeks. If the transmitter's sensor has
recently been replaced, a rough calibration may be performed at installation but another
calibration must be performed 4-6 weeks later.
WARNING: The controller is not an active gas monitoring device during the calibration
procedure.
Calibration Kit Humidifier Tube
The ppm hydrogen detector requires normal atmospheric humidity levels to respond properly to
hydrogen. Normal atmospheric humidity variations do not affect the detector’s response to
hydrogen in ambient air, but the ultra low humidity level of gas from a calibration cylinder
requires that the calibration sample be humidified for the detector to respond properly. The
calibration kit for the ppm hydrogen transmitter includes a humidifier tube that is not normally
included in other calibration kits. This humidifier tube humidifies the calibration sample flowing
through it by absorbing humidity from the ambient air and adding it to the sample. The humidifier
tube is included in the “Parts List” on page 21.
WARNING: A humidifier tube must be used when calibrating the ppm hydrogen transmitter
for the detector to respond properly to the calibration gas. Failure to use a
humidifier tube will result in an inaccurate calibration.

18 • Calibration 65-2445-XX PPM Hydrogen Transmitter
Materials
• 0.5 LPM fixed flow regulator with an on/off knob
• calibration cup
• humidifier tube
• calibration gas cylinder with a full-scale concentration in a balance of air
• calibration gas cylinder with a half-scale concentration in a balance of air
Preparing for Calibration
1. Screw the calibration cup onto the bottom of the hydrogen detector.
2. Use the humidifier tube to connect the regulator to the calibration cup.
3. Set a voltmeter to measure in the millivolt (mV) range.
4. Remove the junction box cover, then plug the voltmeter leads into the test points on the
amplifier.
Plug the positive lead into the red + test point; plug the negative lead into the black - test
point.
5. Place the controller into its calibration mode or disable external alarms.
NOTE: Calibrating the ppm hydrogen transmitter may cause alarms. Be sure to put
the controller into its calibration program or disable external alarms before
continuing.
Setting the Zero Reading
The detector’s zero setting is controlled by electronics and is not user-adjustable.
Detection Range Calibration Gas Concentrations
0 - 100 ppm H250 ppm H2 AND 100 ppm H2
0 - 500 ppm H2250 ppm H2 AND 500 ppm H2
0 - 1,000 ppm H2500 ppm H2 AND 1,000 ppm H2
0 - 2,000 ppm H21,000 ppm H2 AND 2,000 ppm H2

65-2445-XX PPM Hydrogen Transmitter Calibration • 19
Setting the Span Reading
If the transmitter has been recently installed, do not adjust the factory setting on the Fine, Coarse,
or Linear pots until the transmitter has been on power for 4-6 weeks. If the transmitter's sensor has
recently been replaced, a rough calibration may be performed at installation but another
calibration must be performed 4-6 weeks later.
Setting the span reading involves configuration of the COARSE and FINE span pots. To correctly
set the span reading, perform the following:
1. Screw the regulator into the full-scale, air-balanced calibration cylinder.
2. Turn the regulator knob counterclockwise to open the regulator.
3. Make sure the LINEAR pot is set at roughly mid-range, or at least 6 turns from either end.
4. Allow the calibration gas to flow for 2 minutes.
5. Make span calibration adjustments as outlined in Table 6.
3. Turn the regulator knob clockwise to close the regulator.
4. Unscrew the regulator from the full-scale calibration cylinder.
Setting the Linearization
1. Screw the regulator into the half-scale calibration cylinder.
2. Turn the regulator knob counterclockwise to open the regulator.
3. Allow the calibration gas to flow for 2 minutes.
4. Verify a reading of 300 mV (±2 mV) on the voltmeter. If necessary, use the linear pot on the
amplifier to adjust the reading.
5. Turn the regulator knob clockwise to close the regulator.
6. Unscrew the regulator from the half-scale calibration cylinder.
Table 6: Span Calibration Procedures
Full Scale Span Calibration Instructions
• 2000 ppm H2 1. COARSE pot should be set all the way counterclockwise initially.
2. Adjust to 500 mV (±2 mV) using the FINE pot.
3. If 500 mV cannot be reached, adjust the COARSE pot until the
output slightly exceeds 500 mV then dial it back with the FINE pot.
• 1000 ppm H2
• 500 ppm H2
1. Start with COARSE and FINE pots at mid-range.
2. Use the COARSE pot to get as close to 500 mV as possible.
3. If necessary, use the FINE pot to get all the way to 500 mV (±2 mV).
• 100 ppm H2
• 500 ppm Hexane
1. Set the FINE pot somewhere mid-range.
2. Use the COARSE pot to adjust the output to 500 mV (±2 mV).

20 • Calibration 65-2445-XX PPM Hydrogen Transmitter
Returning to Normal Operation
1. Remove the voltmeter leads from the amplifier test points.
2. Unscrew the calibration cup from the detector.
NOTE: For convenience, leave the regulator and calibration cup connected by the
humidifier tube.
3. Secure the junction box cover to the junction box.
4. When the controller display reading falls below the alarm setpoints, return the controller to
normal operation.
5. Verify that the controller display reading decreases and stabilizes at 0 ppm.
6. Store the components of the calibration kit in a safe and convenient place.