RKI Instruments 65-2395RK-CH4-4 User manual

RKI Instruments, Inc.
www.rkiinstruments.com
65-2395RK-CH4-4
Methane Transmitter
Operator’s Manual
Part Number: 71-0468
Revision: P1
Released: 10/17/18

65-2395RK-CH4-4 Combustible Gas Transmitter
WARNING
Read and understand this instruction manual before
operating transmitter. Improper use of the transmitter could
result in bodily harm or death.
Periodic calibration and maintenance of the transmitter is
essential for proper operation and correct readings. Please
calibrate and maintain this transmitter regularly! Frequency
of calibration depends upon the type of use you have and
the sensor types. Typical calibration frequencies for most
applications are between 6 and 12 months, but can be
required more often or less often based on your usage.

65-2395RK-CH4-4 Combustible Gas Transmitter
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 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. 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:
Warranty is voided by abuse including mechanical damage, alteration, rough handling, or
repair procedures not in accordance with the operator’s manual. This warranty indicates
the full extent 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 A
PARTICULAR PURPOSE. IN NO 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 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.
a) Absorbent cartridges d) Batteries
b) Pump diaphragms and valves e) Filter elements
c) Fuses

65-2395RK-CH4-4 Combustible Gas Transmitter
Table of Contents
Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Specifications. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Methane Detector . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Calibration Cup/Splash Guard . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Amplifier . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Amplifier Junction Box . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Detector Junction Box. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Mounting the Methane Transmitter. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Wiring the Detector to the Amplifier. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Wiring the Amplifier to a Controller. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Startup. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Introducing Incoming Power . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Setting the Zero Signal. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Maintenance. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Preventive Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Replacing Components of the Methane Transmitter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Calibration Frequency . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
Determining Response Time . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
Calibration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
Preparing for Calibration. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
Setting the Zero Reading . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
Setting the Response Reading. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
Returning to Normal Operation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
Parts List . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23

65-2395RK-CH4-4 Combustible Gas Transmitter • 5
Overview
This manual describes the 65-2395RK-CH4-4 methane 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 methane transmitter.
Specifications
Table 1 lists specifications for the methane transmitter.
WARNING: When using the 65-2395RK-CH4-4, you must follow the instructions and
warnings in this manual to assure proper and safe operation of the
65-2395RK-CH4-4 and to minimize the risk of personal injury. Be sure to
maintain and periodically calibrate the 65-2395RK-CH4-4 as described in
this manual.
Table 1:Specifications
Description Specification
Target Gas Methane (CH4)
Area Classification Explosionproof for Class I, Groups B, C, and D
Sampling Method Diffusion
Signal Output 4 to 20 mA
Detection Range 0 to 100% volume
Response Time 90% in 45 seconds
Operating Temperature -4°F to 122°F (-20°C to 50°C)
Accuracy ± 5% of reading or ± 2% of full scale (whichever is greater)

6 • 65-2395RK-CH4-4 Combustible Gas Transmitter
Description
The 65-2395RK-CH4-4 methane transmitter utilizes an infrared type of detector which has
some advantages over a catalytic type of combustible detector. The infrared detector will
generally have a longer service life than a catalytic detector, it will require calibration less
often, and it can detect methane even if there is no oxygen in the sample which allows
detection of methane in an inert atmosphere.
This section describes the components of the methane transmitter. The transmitter is a 4 -
20 mA type detector head. It consists of the methane detector, calibration cup/splash
guard, amplifier, the amplifier junction box, and the detector junction box. The two-
junction-box configuration is intended for situations where the detector needs to be
installed at an inaccessible location. The detector junction box can be installed at the
inaccessible location and the amplifier junction box can be installed in a more readily
accessible area.
Figure 1: Methane Transmitter Component Location
G S
LEL PWR / SIG
BR W
Amplifier
Amplifier J-Box
IR CH4Detector
Terminal Strip
Detector J-Box
SPAN ZERO
Sensor
Cu rrent
mA
Calibration Cup/Splash Guard

65-2395RK-CH4-4 Combustible Gas Transmitter • 7
Infrared CH4 Detector
The infrared %volume CH4detector is made up of a miniature infrared CH4detector
housed and encapsulated in a pipe nipple. The pipe nipple has 3/4” NPT threads on each
end and a 1 1/4” hex that allows removal or installation of the detector with a wrench. A
porous flame arrestor that is coated with a hydrophobic film that repels liquids is on one
end of the detector and allows sample gas to enter the detector. Four color coded leads,
red, white, green, and black, extend from the other end of the detector. The leads allow
you to connect the detector to the amplifier.
Calibration Cup/Splash Guard
A calibration cup/splash guard is installed on the IR CH4detector. A fitting at the bottom
of the calibration cup/splash guard allows a length of tubing to be connected for
calibration and routed to a more easily accessible location. The calibration cup/splash
guard also protects the detector.
Amplifier
The amplifier is located in the amplifier junction box. The amplifier converts the electrical
output from the detector to a 4 to 20 mA signal that corresponds to the detection range
and transmits the signal to a gas monitoring controller. A foam gasket that orients the
amplifier and keeps it from rotating is installed on the bottom of the amplifier. A label on
the amplifier indicates the detector drive current. This drive current is factory set to 148
mA. The amplifier includes the detector terminal strip, controller terminal strip, span pot,
zero pot, and test points (see Figure 2).
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 methane transmitter to a
controller.
GWRB
Controller Terminal
Strip
PWR / SIGLEL S
Sensor
Current
mA
Detector Terminal
Strip
SPAN
ZERO
- Test Point
+ Test Point
Jumper Pins,
Factory Use Only
Zero Pot
Span Pot
Factory Adjust Pot

8 • 65-2395RK-CH4-4 Combustible Gas Transmitter
Detector Terminal Strip
The detector terminal strip is a four position plug-in style terminal strip located below the
controller terminal strip. Use the detector terminal strip to connect the IR CH4detector to
the amplifier.
NOTE: See “Wiring the Detector to the Amplifier” on page 11 for all wiring procedures
related to the transmitter.
Zero Pot
The zero pot is located in the upper left corner of the amplifier (see Figure 2). Use a small
flat blade screwdriver to turn the zero pot’s adjustment screw and adjust the amplifier’s
zero (fresh air) output during the start-up and calibration procedures. Turn the adjust-
ment screw clockwise to increase the zero output and counterclockwise to decrease the
zero output.
Span Pot
The span pot is located to the right of the zero pot (see Figure 2). Use a small flat blade
screwdriver to turn the span pot’s adjustment screw and adjust the amplifier’s gas
response output during the calibration procedure. Turn the adjustment screw clockwise to
increase the gas response and counterclockwise to decrease the gas response.
CAUTION: The amplifier includes two additional potentiometers. They are factory-set. Do not
adjust them.
Test Points
The test points are on the left side of the amplifier (see Figure 2). The test points produce a
100 mV 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 in the lower left corner is the negative (-) test
point and the red test point below the zero pot is the positive (+) test point.
Amplifier Junction Box
The amplifier junction box protects the amplifier and wiring connections made to the
amplifier. Use the top 3/4’’ conduit hub to connect wiring from the amplifier to the
controller. Use the bottom 3/4” conduit hub to wire the remotely installed IR CH4
detector. Use the cover on the front of the junction box to access the interior of the junction
box. The amplifier is factory installed in the junction box. Three spacers installed on the
back of the junction box controls the distance of the junction box from a mounting surface.
A ground boss near the top conduit hub provides an external earth ground connection.
Detector Junction Box
The detector junction box is intended to be installed remotely from the amplifier junction
box. The IR CH4detector is factory installed in the bottom 3/4” conduit hub. A terminal
strip is provided for wiring connections and the detector is factory wired to one side of
this terminal strip. The other side of the terminal strip is for user-supplied wiring to the
detector terminal strip located in the amplifier junction box. This wiring should go
through the top 3/4” conduit hub. Three spacers installed on the back of the junction box
controls the distance of the junction box from a mounting surface. A ground boss near the
top conduit hub provides an external earth ground connection.

65-2395RK-CH4-4 Combustible Gas Transmitter • 9
Installation
This section describes procedures to mount the methane transmitter in the monitoring
environment and wire the transmitter to a controller.
Mounting the Methane Transmitter
1. Select a mounting site that is representative of the monitoring environment. Consider
the following when you select the mounting site.
• For the amplifier junction box, select a site where the junction box is not likely to
be bumped or disturbed. Make sure there is sufficient room to perform start-up,
maintenance, and calibration procedures. The site should be easily accessible.
• For the detector junction box, select a site where the target gas is likely to be found
first. For lighter gases, mount the detector near the ceiling; for heavier gases,
mount the detector near the floor.
• The junction boxes should be mounted no further than 200 feet from each other.

10 • 65-2395RK-CH4-4 Combustible Gas Transmitter
Figure 3: Mounting the Methane Transmitter
2. At the monitoring site you select, hang or mount the detector junction box with the
detector facing down (see Figure 3).
3. Install 3/16 inch I.D. flexible polyurethane tubing to the fitting at the bottom of the
calibration cup/splash guard and route it to an accessible area that is close to the
amplifier junction box. See the “Parts List” on page 23 for available tubing.
.382.70
J-Box
Rubber
Spacer,
3X
IR CH4
Detector
.75
3/4 NPT
Female
3.65
Calibration
Cup/Splash
Guard
9.00 MAX
5.25

65-2395RK-CH4-4 Combustible Gas Transmitter • 11
Wiring the Detector to the Amplifier
WARNING: Always verify that the power to the controller is off before you make
wiring connections.
1. Confirm that no power is being applied to the amplifier. If the amplifier has already
been connected to a controller, turn off the controller and turn off or unplug power to
the controller.
2. Remove the detector junction box’s cover from the junction box.
3. Remove the amplifier junction box’s cover from the junction box.
4. Guide a four-conductor, shielded cable or four wires in conduit through the top
conduit hub of the detector junction box. To make wiring more convenient, use wire
colors that correspond to the detector wire colors: red, white, green, and black.
NOTE: Consult RKI Instruments, Inc. for cable lengths longer than 200 feet.
5. Connect the wires to the terminal block in the detector junction box.
6. Secure the detector junction box’s cover to the junction box.
7. Guide the other end of the four-conductor, shielded cable or four wires in conduit
through the bottom conduit hub of the amplifier junction box.
8. 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.
9. Pull out the detector terminal strip and connect the four wires to the terminal strip as
follows (see Figure 4).
• Connect the wire corresponding to the detector’s red wire to the LEL “R”
terminal.
• Connect the wire corresponding to the detector’s white wire to the LEL “W”
terminal.
• Connect the wire corresponding to the detector’s green wire to the LEL “G”
terminal.
• Connect the wire corresponding to the detector’s black wire to the LEL “B”
terminal.
CAUTION: If shielded cable is used, leave the cable shield’s drain wire disconnected and
insulated at the detector junction box. You will connect the opposite end of the cable’s
drain wire to the amplifier junction box’s chassis (earth) ground.

12 • 65-2395RK-CH4-4 Combustible Gas Transmitter
Figure 4: Wiring the Detector to the Amplifier
10. Reinstall the detector terminal strip into its socket.
11. If shielded cable is used, connect the cable’s drain wire to an available chassis (earth)
ground at the amplifier junction box. The amplifier mounting screw is a convenient
grounding location. Install a lug on the shield drain wire or wrap the shield drain wire
around the mounting screw. Do not connect the shield drain wire at the detector
junction box.
GRB
LEL S
PWR/ SIG
W
Amplifier
Black
Green
White
Red
Cable
Shield
Detector
Terminal
Strip
Detector J-Box
Calibration Cup/Splash Guard
Amplifier
J-Box
IR CH4 Detector
Black
Green
White
Red

65-2395RK-CH4-4 Combustible Gas Transmitter • 13
Wiring the Amplifier to a Controller
1. Turn off the controller.
2. Turn off or unplug power to the controller.
3. Remove the amplifier junction box’s cover from the junction box.
4. Guide a three-conductor, shielded cable, or three wires in conduit through the top
conduit hub of the amplifier junction box.
5. Pull out the controller terminal strip, and connect the three wires to the terminal strip
as follows (see Figure 5).
• 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 amplifier junction box. You will connect the opposite end of the
cable’s drain wire to the controller’s chassis (earth) ground.
6. Reinstall the controller terminal strip into its socket.
7. Secure the amplifier junction box’s cover to the junction box.
8. Route the cable or wires leading from the amplifier junction box 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.
9. Connect the wires to the applicable detector/transmitter terminal strip at the
controller as shown in Figure 5.

14 • 65-2395RK-CH4-4 Combustible Gas Transmitter
Figure 5: Wiring the Amplifier to a Controller
10. 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.
Detector Wires
Green
White
Red
Amplifier (Transmitter)
Cable Shield
- (DC Ground)
+24VDC
4-20mAIn(S)
Controller or
Recording Device
Amplifier
J-Box
B
R W G PW R / SIG
Black
LEL
S

65-2395RK-CH4-4 Combustible Gas Transmitter • 15
Start Up
This section describes procedures to start up the methane 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.
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.
NOTE: When first powered up, the transmitter will enter about a one minute period
when the 4-20 mA output is stabilizing and may be above the controller alarm
points or well below zero momentarily. RKI controllers have a one minute
warmup period when the controller does not display any gas reading or give any
alarm indication. The methane transmitter’s 4-20 mA signal should be stable by
the time the controller’s warmup period is over.
CAUTION: Allow the detector to warm up for 5 minutes before you continue with the next
section, “Setting the Zero Signal”.
Setting the Zero Signal
WARNING: Do not remove the junction box cover while the circuits are energized
unless the area is determined to be non-hazardous. Keep the junction box
cover tightly closed during operation.
NOTE: If you can verify that the methane transmitter is in a fresh air environment, you
do not need to apply zero air to the detector before adjusting the zero reading.
The procedure below describes applying zero emission air, usually called zero air, using a
calibration kit that includes a calibration cup, calibration gas, sample tubing, and a fixed
flow regulator with an on/off knob. RKI Instruments, Inc. recommends using a 0.5 LPM
(liters per minute) fixed flow regulator.
1. Unscrew and remove the amplifier junction box’s cover from the junction box.
2. Set a voltmeter to measure in the millivolt (mV) range.
3. 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.
4. Screw the regulator into the zero air calibration cylinder.
5. Use the flexible tubing coming from the calibration cup/splash guard to connect the
regulator to the calibration cup.
6. Turn the regulator’s on/off knob counterclockwise to open it. Gas will begin to flow.

16 • 65-2395RK-CH4-4 Combustible Gas Transmitter
7. Allow the gas to flow for the length of time determined in “Determining Response
Time” on page 20.
8. Verify a voltmeter reading of 100 mV (±2 mV).
9. If necessary, use a small flat-blade screwdriver to adjust the zero pot until the
voltmeter reading is 100 mV (±2 mV).
10. Turn the regulator’s on/off knob clockwise to close it.
11. Disconnect the calibration cup/splash guard’s flexible tubing from the regulator.
NOTE: Do not disconnect the flexible tubing from the calibration cup/splash guard.
12. Unscrew the regulator from the zero air calibration cylinder.
13. Store the components of the calibration kit in a safe and convenient place.
14. Remove the voltmeter leads from the test points.
15. Secure the junction box cover to the junction box.
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 methane transmitter. It includes daily and biannual procedures.
Daily
Verify a display reading of 0 %volume at the controller. Investigate significant changes in
the display reading.
Biannually
Calibrate the methane transmitter as described in “Calibration” on page 21 of this manual.

65-2395RK-CH4-4 Combustible Gas Transmitter • 17
Troubleshooting
The troubleshooting guide describes symptoms, probable causes, and recommended
action for problems you may encounter with the methane transmitter.
NOTE: This troubleshooting guide describes transmitter problems only. See the
controller operator’s manual for problems you may encounter with the
controller.
Replacing Components of the Methane Transmitter
This section includes procedures to replace the methane detector and amplifier.
Replacing the IR CH4Detector
NOTE: The IR CH4detector is installed on the junction box that does not house the
amplifier. This junction box was likely installed somewhere difficult to access.
1. Turn off the controller.
2. Turn off or unplug power to the controller.
3. Unscrew the calibration cup/splash guard from the detector.
4. Remove the detector junction box’s cover from the junction box.
Table 2:Troubleshooting the Methane Transmitter
Condition Symptom(s) Probable Causes Recommended Action
Fail Condition • Controller indicates a
fail condition.
• The detector-to-
amplifier or amplifier-
to-controller wiring is
disconnected or
misconnected.
• The transmitter’s zero
reading is low enough
to cause a fail
condition.
• The transmitter is
malfunctioning.
1. Verify that the detector-to-amplifier
and amplifier-to-controller 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.
Slow or No
Response/
Difficult or
Unable to
Calibrate
• Unable to accurately
set the zero or
response reading
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 calibration gas is
not an appropriate
concentration.
• The transmitter is
malfunctioning.
• The flexible tubing to
the calibration cup/
splash guard has
become kinked,
blocked, or
disconnected.
1. Verify that the calibration cylinder
contains an adequate supply of a
fresh test sample.
2. Verify that the regulator used for
calibration is a 0.5 LPM regulator.
3. Verify that the calibration gas
concentration is appropriate for the
transmitter. The concentration should
be in the detection range, preferably
about half of the detection range.
4. Verify that the flexible tubing to the
calibration cup/splash guard is clear
and connected to the calibration cup/
splash guard.
5. If the calibration/response difficulties
continue, replace the detector.
6. If the calibration/response difficulties
continue, contact RKI for further
instruction.

18 • 65-2395RK-CH4-4 Combustible Gas Transmitter
5. Disconnect the detector leads from the terminal block in the detector junction box.
Note the position of the color-coded leads as you remove them.
6. Unscrew the detector from the detector junction box.
7. Guide the detector leads of the replacement detector through the bottom conduit hub
of the detector junction box, then screw the mounting threads of the detector into the
conduit hub. If necessary for environmental conditions, apply thread sealant or Teflon
tape to the hub and/or detector threads to seal them.
8. Connect the detector leads to the terminal block the same way the old detector was
wired (see Figure 4 on page 12).
9. Screw the calibration cup/splash guard onto the new detector.
10. Reinstall the detector junction box cover.
11. Turn on or plug in power to the controller.
12. Turn on the controller and place it into normal operation.
NOTE: When first powered up, the transmitter will enter about a one minute period
when the 4-20 mA output is stabilizing and may be above the controller alarm
points or well below zero momentarily. RKI controllers have a one minute
warmup period when the controller does not display any gas reading or give any
alarm indication. The methane transmitter’s 4-20 mA signal should be stable by
the time the controller’s warmup period is over.
CAUTION: Allow the replacement detector to warm up for 5 minutes before you continue with
the next step.
13. Calibrate the transmitter as described in “Calibration” on page 21 of this manual.
Replacing the Amplifier
NOTE: The amplifier is not housed in the same junction box as the IR CH4detector. The
amplifier junction box should be somewhere accessible.
1. Turn off the controller.
2. Turn off or unplug power to the controller.
3. Remove the amplifier junction box’s cover from the junction box.
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.
7. Place the new amplifier in the same position as the old amplifier. 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.
8. Install the new amplifier into the junction box with the screw, lock washer, and flat
washer you removed in step 5 above.

65-2395RK-CH4-4 Combustible Gas Transmitter • 19
9. Install the detector and controller terminals strips into their sockets on the new
amplifier as shown in Figure 5 on page 14 of this manual. If controller leads or
detector leads were removed during this procedure, refer to Table 3 and Table 4
below.
NOTE: When a transmitter is first powered up with a new amplifier, the initial output
may be either high or below zero depending on the setting of the zero pot. 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.
NOTE: When first powered up, the transmitter will enter about a one minute period
when the 4-20 mA output is stabilizing and may be above the controller alarm
points or well below zero momentarily. RKI controllers have a one minute
warmup period when the controller does not display any gas reading or give any
alarm indication. The methane transmitter’s 4-20 mA signal should be stable by
the time the controller’s warmup period is over.
12. Allow the transmitter to warm-up for 5 minutes.
13. Calibrate the transmitter as described in “Calibration” on page 21 of this manual.
Table 3:Reconnecting the Amplifier
to the Controller
Amplifier Controller
Terminal Strip
Controller
Transmitter Terminal
Strip (typical)
PWR/SIG “-” - (DC -)
PWR/SIG “S” S (4 - 20 mA In)
PWR/SIG “+” + 24V
Table 4:Reconnecting the CH4
Detector to the Amplifier
Amplifier Detector
Terminal Strip Detector Lead
DETECTOR “R” RED
DETECTOR “W” WHT
DETECTOR “G” GREEN
DETECTOR “B” BLK

20 • 65-2395RK-CH4-4 Combustible Gas Transmitter
Calibration Frequency
Although there is no particular calibration frequency that is correct for all applications, a
calibration frequency of every 6 months is adequate for most infrared methane transmitter
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 calibration adjustments are minimal at calibration, then a
calibration frequency of every 9 to 12 months is adequate.
If an application is very demanding, for example if the environment is not well controlled,
then more frequent calibration than every 6 months may be necessary.
Determining Response Time
Since the detector junction box is installed remotely from the amplifier, the response time
of the detector will depend on the length of flexible tubing that is attached to the
calibration cup/splash guard. To determine the response time based on the length of
tubing connected:
1. Place the controller into its calibration mode or disable external alarms.
2. Note the current gas reading displayed at the controller.
3. Screw the regulator into the calibration cylinder. Do not use a zero air cylinder for this
operation.
4. Use the flexible tubing coming from the calibration cup/splash guard to connect the
regulator to the calibration cup.
5. Turn the regulator’s on/off knob counterclockwise to open the regulator. Gas will
begin to flow. Take note of the time or start a stopwatch.
6. When you first start to notice an increase in the gas reading, note how much time
passed between starting the gas flow and noticing a reading response.
7. Turn the regulator’s on/off knob clockwise to close the regulator.
8. Unscrew the regulator from the calibration cylinder.
9. Disconnect the calibration cup/splash guard’s flexible tubing from the regulator.
NOTE: Do not disconnect the flexible tubing from the calibration cup/splash guard.
10. Add 1 minute to the length of time determined in step 6. This is the response time for
the detector. When performing a response test, zero adjustment, or span adjustment,
gas must be applied for this length of time.