RKI Instruments 65-2435RK User Manual

65-2435RK

Hydrogen Compensated Carbon

Monoxide Transmitter

Operator’s Manual

Part Number: 71-0073RK

Revision: A

Released: 2/20/14

RKI Instruments, Inc.

www.rkiinstruments.com

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.

a) Absorbent cartridges d) Batteries

b) Pump diaphragms and valves e) Filter elements

c) Fuses

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.

2 • 65-2435RK CO Transmitter

Table of Contents

Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

Specifications. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

Description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

CO Detector. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

Amplifier . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

Junction Box . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

Installation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

Mounting the CO Transmitter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

Wiring the CO Transmitter to a Controller . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

Startup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

Introducing Incoming Power. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

Setting the Zero Signal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

Operating With a Background of Hydrogen . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

Preventive Maintenance. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

Troubleshooting. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

Replacing Components of the CO Transmitter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

Setting the Null Potentiometer. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

Calibration. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

Preparing for Calibration. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

Setting the Zero Reading . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

Setting the Response Reading . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

Returning to Normal Operation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

Parts List . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

65-2435RK CO Transmit ter • 3

Overview

This manual describes the hydrogen compensated carbon monoxide (CO) transmitter. This manual
also describes how to install, start up, maintain, and calibrate the transmitter. A parts list at the end
of this manual lists replacement parts and accessories for the CO transmitter.

Specifications

Table 1 lists specifications for the CO transmitter.

Table 1: Specifications

Target Gas Carbon Monoxide (CO)

Area Classification Explosionproof for Class I, Groups B, C, and D

Input Voltage 19 - 30 VDC

Sampling Method Diffusion

Signal Output 4 to 20 mA

Detection Range 0 to 300 PPM (parts per million)

Response Time 90% in 30 seconds

4 • 65-2435RK CO Transmitter

Description

This section describes the components of the CO transmitter. The transmitter consists of the CO
detector, amplifier, and junction box.

Tes t Point (-)

Tes t Poin t (+)

Null

Pot enti om eter

Spa n Potentiom eter

Zero Potentiom eter

Carbon Mo nox i de D etector

TP+

NULL

4-20mATransmitter

57-1252RK

SPAN

ZERO

3/4" Conduit Hub

Terminal Strip

TP

FB

24V

PWR

BLK

GRN

BRN

WHT

SENSOR

RED

Carbon Monoxide
Am pli fi e r

Securing Screw (2)

Detector Hous i ng

Ca p Ga s k e t (x 2 )

Detector Hous i n g Cap

Flame Arrestor

Figure 1: CO Transmitter Component Location

CO Detector

The CO detector includes the detector housing and sensor.

Detector Housing

The detector housing protects the sensing components within the housing. Use the mounting
threads at the top of the housing to screw the CO detector into the bottom conduit hub of the
junction box. Use the removable cap near the bottom of the housing to access the sensor for
maintenance or replacement. The cap protects the sensor from damage and includes a flame
arrestor which contains any sparks which may occur within the detector housing. Two cap gaskets
seal the interface between the housing and cap.

Two wires extend from the top of the detector housing. Use these wires to connect the CO detector
to the amplifier. The housing includes a four-socket pattern. This socket pattern accepts the sensor’s
four pins to secure the sensor within the detector housing. A pre-amplifier, located between the
sockets and two interconnect wires, conditions the sensor’s signal before the signal reaches the
amplifier.

Sensor

The sensor is secured within the sensor housing by the four pins. Through a series of chemical and
electrical reactions, the sensor produces an electrical output that is proportional to the detector
range of the transmitter.

65-2435RK CO Transmit ter • 5

Charcoal Filter

The disc-shaped charcoal filter is secured to face of the CO sensor with a rubber boot. The charcoal
filter prevents interference gases (hydrogen sulfide [H

producing false CO readings.

S] and certain hydrocarbons) from

2

Amplifier

The amplifier converts the electrical output from the sensor 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 terminal strip, span potentiometer, zero potentiometer, and test points (see
Figure 1.)

Terminal Strip

The terminal strip is a seven-point terminal strip on the right side of the amplifier. Use the terminal
strip to connect the CO detector to the amplifier and the amplifier to a controller. The terminal strip
is a plug-in style which can be removed for wiring by pulling up on it.

NOTE: The CO detector is factory-wired to the amplifier. See the Installation section of this

manual for all wiring procedures related to the transmitter.

Span Potentiometer

The span potentiometer is near the bottom of the amplifier. It is to the left of the zero potentiometer.
Use the span potentiometer to adjust the transmitter’s response output during the calibration
procedure.

Zero Potentiometer

The zero potentiometer is to the right of the span potentiometer. Use the zero potentiometer to
adjust the transmitter’s target gas-free output during the start-up and calibration procedures.

Null Potentiometer

The null potentiometer is on the left side of the amplifier. It is used to adjust the transmitters
hydrogen compensation when a CO sensor is replaced.

CAUTION: The null potentiometer is factory set before shipment. It should only be adjusted in

the field when the CO sensor is replaced. This adjustment is made only once after
installing a new sensor. Do not adjust this pot when calibrating the CO transmitter.

Test Points

The test points (labeled TP- and TP+) are near the top of the amplifier. 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.

Junction Box

Use the junction box to install the CO 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).

NOTE: The CO detector and amplifier are factory-mounted to the junction box.

Use the junction box’s two mounting holes to mount the CO transmitter to a vertical surface at the

6 • 65-2435RK CO Transmitter

Installation

monitoring site. Use the cover on the front of the junction box to access the interior of the junction
box.

This section describes procedures to mount the CO transmitter in the monitoring environment and
wire the transmitter to a controller.

Mounting the CO 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.

NOTE: If your application does not require a specific mounting site, mount the transmitter at

approximately breathing level.

6.1

1.1

3.94

5.2

2.75

5.46

Ø.25Mouting Holes (2X)

3/4 C on du it Hub

8.3 ma x

2.85 max

Figure 2: Mounting the CO Transmitter

If the CO 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 two wires that extend from the top of the CO detector through the bottom conduit
hub of the junction box.

4. Screw the CO 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 CO transmitter with the detector facing down (see Figure 2.)

65-2435RK CO Transmit ter • 7