RKI Instruments 65-2405RK-05-04 User manual

RKI Instruments, Inc.
www.rkiinstruments.com
65-2405RK-05-04
Combustible Gas Transmitter
Operator’s Manual
Part Number: 71-0547
Revision: P1
Released: 2/1/21

2 • 65-2405RK-05-04 Combustible Gas Transmitter
WARNING
Read and understand this instruction manual before operating detec-
tor. Improper use of the detector could result in bodily harm or death.
Periodic calibration and maintenance of the detector is essential for
proper operation and correct readings. Please calibrate and maintain
this detector regularly! Frequency of calibration depends upon the
type of use you have and the sensor types. Typical calibration frequen-
cies for most applications are between 3 and 6 months, but can be
required more often or less often based on your usage.

65-2405RK-05-04 Combustible Gas Transmitter • 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 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

4 • 65-2405RK-05-04 Combustible Gas Transmitter
Table of Contents
Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Specifications. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Combustible Gas Detector . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Amplifier . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Amplifier Junction Box . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Detector Junction Box . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Installation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Mounting the Combustible Gas Transmitter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Wiring the Detector to the Amplifier . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Wiring the Amplifier to a Controller . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Startup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Introducing Incoming Power . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Setting the Zero Signal. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Preventive Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Replacing Components of the Combustible Gas Transmitter . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Calibration Frequency . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
Determining Response Time . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
Calibration. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
Preparing for Calibration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
Setting the Zero Reading . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
Setting the Response Reading . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
Returning to Normal Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
Parts List . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

65-2405RK-05-04 Combustible Gas Transmitter • 5
Overview
This manual describes the 65-2405RK-05-04 combustible gas 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 combustible gas transmitter.
Specifications
WARNING: Do not use this product in a manner not specified in this manual.
Table 1 lists specifications for the combustible gas transmitter.
NOTE: The following symbol on the detector label is a caution to the user to refer to this
documentation for installation instructions:
WARNING: When using the 65-2405RK-05-04, you must follow the instructions and warnings in
this manual to assure proper and safe operation of the 65-2405RK-05-04 and to
minimize the risk of personal injury. Be sure to maintain and periodically calibrate
the 65-2405RK-05-04 as described in this manual.
Table 1:Specifications
Description Specification
Target Gas Combustible gas, methane calibration standard1
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% LEL
Accuracy ± 5% of reading or ± 2% LEL (whichever is greater)
Response Time 90% in 45 seconds
Operating Temperature -40°F to 167°F (-40°C to 75°C)
1If calibration to a combustible gas other than methane is required, specify the required
calibration gas at time of order.
!

6 • 65-2405RK-05-04 Combustible Gas Transmitter
Description
This section describes the components of the combustible gas transmitter. The transmitter is a 4 - 20
mA type detector head. It consists of the combustible gas detector, amplifier, and junction box.
Figure 1: Combustible Gas Transmitter Component Location
Combustible Gas Detector
The combustible gas detector is a catalytic type detector that produces an electrical output that
corresponds to the detection range. It is 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 flame arrestor guard
is located at the bottom of the detector and is permanently bonded to the detector housing. The flame
arrestor guard protects the flame arrestor from impact damage. Four color-coded leads extend from the
top of the detector. The leads allow you to connect the detector to the amplifier.
S
LEL PWR /SIG
BR W G
Detector
Junction Box
ZERO
Terminal Strip
SPAN
Sensor C urrent
mA
Amplifier
Junction Box
Combustible Gas Detector
Calibration Cup/SplashGuard

65-2405RK-05-04 Combustible Gas Transmitter • 7
Amplifier
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 and is dictated by the
combustible gas to which the detector is calibrated. Consult RKI Instruments, Inc. if you plan to
change the calibration gas for the transmitter, for example from a methane calibration to a hexane
calibration. The amplifier includes the detector terminal strip, controller terminal strip, span pot, zero
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.
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 detector to the amplifier.
NOTE: See “Wiring the Amplifier to a Controller” on page 12 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.
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.
PWR / SIG
S
Controller Terminal Strip
Detector Terminal Strip
G B
ZERO
SPAN
Span Pot
Zero Pot
RLEL
W
- Test Point
Factory Adjust Pot, x2
+ Test Point

8 • 65-2405RK-05-04 Combustible Gas Transmitter
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 NPT conduit hub to connect wiring from the amplifier to the controller. Use the bottom
3/4 NPT conduit hub to wire the remotely installed combustible gas 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.
Detector Junction Box
The detector junction box is intended to be installed remotely from the amplifier junction box. The
combustible gas detector is factory installed in the bottom 3/4 NPT 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 NPT conduit hub. Three spacers
installed on the back of the junction box controls the distance of the junction box from a mounting
surface.
Installation
This section describes procedures to mount the combustible gas transmitter in the monitoring
environment and wire the transmitter to a controller.
Mounting the Combustible Gas 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.

65-2405RK-05-04 Combustible Gas Transmitter • 9
Figure 3: Mounting the Combustible Gas Transmitter
2. At the monitoring site you select, hang or mount the 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 “Parts
List” on page 21 for available tubing.
.382.70
3/4 NPT Female
Rubber
Spacer,
3X
1.13
5.25
9.80 Max
Ø3.65
Combustible
Gas
Detector
Calibration
Adapter/
Splash
Guard

10 • 65-2405RK-05-04 Combustible Gas Transmitter
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 detector leads 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.