RKI Instruments 65-2400RK User manual

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65-2400RK
Combustible Gas Transmitter
Operator’s Manual
Part Number: 71-0060RK
Revision: C
Released: 1/31/13

65-2400RK Combustible Gas Transmitter
WARNING
Read and understand this instruction manual before operating
detector. 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 frequencies for most applications are between
3 and 6 months, but can be required more often or less often
based on your usage.

65-2400RK 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

65-2400RK Combustible Gas Transmitter
Table of Contents
Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Specifications. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Combustible Gas Detector. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Amplifier . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Junction Box. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Mounting the Combustible Gas Transmitter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Wiring the Combustible Gas Transmitter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Startup. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Introducing Incoming Power . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Setting the Zero Signal. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Maintenance. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Preventive Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Replacing Components of the Combustible Gas Transmitter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Calibration Frequency . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Calibration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Preparing for Calibration. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Setting the Zero Reading . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Setting the Response Reading. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Returning to Normal Operation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Parts List . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

65-2400RK Combustible Gas Transmitter • 1
Overview
This manual describes the 65-2400RK 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
Table 1 lists specifications for the combustible gas transmitter.
WARNING: When using the 65-2400RK, you must follow the instructions and warnings
in this manual to assure proper and safe operation of the 65-2400RK and to
minimize the risk of personal injury. Be sure to maintain and periodically
calibrate the 65-2400RK as described in this manual.
Table 1:Specifications
Description Specification
Target Gas Combustible gas
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

2 • 65-2400RK 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 includes the sensing elements, flame arrestor, detector
housing, and detector leads.
Sensing Elements
Two sensing elements are protected within the detector assembly. Through a series of
thermal and electronic reactions, these elements produce an electrical output that is
proportional to the detection range of the transmitter.
Flame Arrestor
The porous flame arrestor allows the target gas to diffuse into the detector assembly and
contact the sensing elements. The flame arrestor also contains sparks within the detector.
GND
24V
4-20
RED
WHT
GRN
BLK
SENSOR POWER/SIG
TP+
TP-
Combustible gas
amplifier
Interconnect
terminal strip
Test point (-)
Securing screw (2)
Test point (+)
Reducer
(3/4 in. x 1/2 in.)
Combustible gas
detector
Zero potentiometer
Span potentiometer
Potentiometer
(factory set)
Potentiometer
(factory set)
Jumper pins
(factory use only)

65-2400RK Combustible Gas Transmitter • 3
Detector Housing
The sensing elements and flame arrestor are installed within the detector housing.
Mounting threads (1/2 in. NPT) at the top of the detector allow you to mount the
combustible gas detector into the bottom conduit hub of the junction box. A rainshield
screws onto the bottom of the detector. The rainshield helps protect the detector from
debris in the monitoring environment.
Detector Leads
Four color-coded leads extend from the top of the detector. The leads allow you to connect
the combustible gas detector to the amplifier.
Amplifier
The amplifier converts the electrical output from the detector to a 4 to 20 mA signal that is
proportional to the detection range and transmits the signal to a gas monitoring controller.
The amplifier includes the interconnect terminal strip, span pot, zero pot, and test points
(see Figure 1).
Interconnect Terminal Strip
The interconnect terminal strip is a seven-point terminal strip. Use the interconnect
terminal strip to connect the combustible gas detector to the amplifier and the amplifier to
a controller.
NOTE: The combustible gas detector is factory-wired to the amplifier. See the
Installation section of this manual for all wiring procedures related to the
transmitter.
Span Pot
The span pot is near the bottom of the amplifier (see Figure 1). Use the span pot to adjust
the transmitter’s response output during the calibration procedure.
Zero Pot
The zero pot is to the right of the span pot (see Figure 1). Use the zero pot to adjust the
transmitter’s target gas-free output during the start-up and calibration procedures.
CAUTION: The amplifier includes two additional potentiometers. They are factory-set. Do not
adjust them.
Test Points
The test points (labeled TP+ and TP-) are to the left of the interconnect terminal strip
(see Figure 1). The test points produce a 100 to 500 mV output that is proportional to the
transmitter’s 4 to 20 mA output. Use the test points and a voltmeter to measure the
transmitter’s output during the start-up and calibration procedures.

4 • 65-2400RK Combustible Gas Transmitter
Junction Box
Use the junction box to install the combustible gas 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 two 3/4 in. conduit hubs to mount the detector
to the junction box (bottom hub) and connect wiring from the amplifier to the controller
(top hub). The detector has 1/2 in. NPT mounting threads, so a 3/4 in NPT. x 1/2 in. NPT
reducer is used to mount it.
NOTE: The combustible gas detector and amplifier are factory-mounted to the
junction box.
Use the junction box’s two mounting holes to mount the combustible gas transmitter to a
vertical surface at the monitoring site. Use the cover on the front of the junction box to
access the interior of the junction box.

65-2400RK Combustible Gas Transmitter • 5
Installation
This section describes procedures to mount the combustible gas transmitter in the
monitoring environment and wire the transmitter to the 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.
• 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 lighter gases,
mount the detector near the ceiling; for heavier gases, mount the detector near the
floor.
Figure 2: Mounting the Combustible Gas Transmitter
If the combustible gas detector is mounted to the junction box, skip to step 5. If not,
continue with step 2.
2. Remove the junction box cover.
3. Guide the four wires that extend from the top of the combustible gas detector through
the bottom conduit hub of the junction box.
4. Screw the combustible gas detector into the bottom conduit hub of the junction box.
5. At the monitoring site, use #10 screws through the junction box’s two mounting holes
to secure the junction box to a vertical surface.
CAUTION: Mount the combustible gas transmitter with the detector facing down (see Figure 2).
2.3 in.
(5.8 cm)
5.2 in.
Note: The junction box is
4.6 in. (11.7 cm) deep.
(13.2 cm)
7.7 in. (max.)
(19.6 cm)
5.46 in.
(13.9 cm)
2.75 in.
(7.0 cm)
0.25 in.
DIA.

6 • 65-2400RK Combustible Gas Transmitter
Wiring the Combustible Gas Transmitter to a Controller
WARNING: Always verify that the power source 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. Verify that the detector leads are wired to the amplifier’s interconnect terminal strip.
If necessary, connect the detector leads to the interconnect terminal strip as shown in
Figure 3.
5. Guide a three-conductor, shielded cable or three wires in conduit through the top
conduit hub of the junction box.
6. Connect the three wires to the interconnect terminal strip as follows (see Figure 3).
• Connect the positive wire to the 24VDC terminal.
• Connect the feedback wire to the 4-20 (FB) terminal.
• Connect the negative wire to the DC - terminal.
CAUTION: If shielded cable is used, leave the cable shield’s drain wire insulated and
disconnected at the transmitter. You will connect the opposite end of the cable’s drain
wire at the controller to chassis ground.
7. Secure the junction box cover to the junction box.
8. Route the cable or wires leading from the combustible gas transmitter through one of
the conduit hubs at the controller housing.
CAUTION: Do not route power and transmitter wiring through the same conduit hub. The
power cable may disrupt the transmission of the transmitter signal to the
controller.
9. Connect the wires to the applicable transmitter terminal strip at the controller as
shown in Figure 3 below.