RKI Instruments 65-2399RK-CH4 User Manual

65-2399RK-CH4

Part Number: 71-0201RK
Revision: A
Released: 4/12/11

Methane Transmitter

Operator’s Manual

RKI Instruments, Inc.

www.rkiinstruments.com

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 tra nsmitt er regula rly! 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.

65-2399RK-CH4 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 fr o m date of shipment
from RKI Instruments, Inc. Any parts found defective withi n tha t 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 ser v ice, and
which must be cleaned, repaired, or replaced on a routine basis. Examples of such items
are:

W arranty 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 , a nd we are not r esponsible for removal or r eplacement costs,
local repair costs, transportation costs, or contingent expenses incurred without our prior
approval.

a) Absorbent cartridges d) Batteries
b) Pump diaphragms and valves e) Filter elements
c) Fuses

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 RK I 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 i ndemnification for a n y a c c ident or damage cause d b y the operation of
this gas monitor, and our warranty is limited to the replacement of parts or our complete
goods.

65-2399RK-CH4 Combustible Gas Trans mitte r

Table of Contents

Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

Specifications. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

Description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

Methane Detector . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

Amplifier . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

Junction Box. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

Mounting the Methane Transmitter. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

Wiring the Methane Transmitter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

Startup. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

Introducing Incoming Power . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

Setting the Zero Signal. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

Maintenance. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

Preventive Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

Replacing Components of the Methane Transmitter. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

Calibration Frequency . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

Calibration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

Preparing for Calibration. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

Setting the Zero Reading. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

Setting the Response Reading. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

Returning to Normal Operation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

Parts List . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

65-2399RK-CH4 Combustible Gas Transmitter

Overview

This manual describes the 65-2399RK-CH4 methane transmitter. This manual also
describes how to install, start up, con fi gure, mainta in, a nd ca librate 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.

Table 1:Specifications

Description Specification

Target Gas Methane (CH
Sampling Method Diffusion

Signal Output 4 to 20 mA
Detection Range 0 to 100% Volume
Response Time 90% in 45 seconds
Operating Temperature
Accuracy ± 5% of reading or ± 2% of full scale (whichever is gr eater)

-4°F to 122°F (-20°C to 50°C)

)

4

WARN IN G: When using the 65-2399RK-CH4, you must follow the instructions and

warnings in this manual to assure proper and safe opera tion of the
65-2399RK-CH4 and to mini mize the risk of personal injury. Be sure to
maintain and periodically calibrate the 65-2399RK-CH4 as described in
this manual.

65-2399RK-CH4 Combus tible Ga s Tr a nsm itter • 1

Description

l

The 65-2399RK-CH4 transmitter is calibrated to methane. The transmitter utilizes an
infrared type of detector which has some advantages over a catalytic type of combustible
detector. The infrared de tector will generally have a longer service life than a catalytic
detector, it will req uire calibration less often, and it can detect methane even if there is no
oxygen in the sample which allows d etection 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, amplifier, and junction box.

Factory Adjust Pot

Jumper Pins,

Factory Use Only

100mV-500mV

Range

Factory Adjust Pot

Span Pot

Zero Pot

+ Test Point (Red)

- Test Point (Black)

Controller Terminal Strip

Amplifier

SPAN

ZERO

Sensor

Current

mA

S

PWR / SIG

BWR
G

LEL

Detector Termina
Strip

J-Box

IR CH4%Vol ume
Detector

Figure 1: Methane Transmitter Component Location

2 • 65-2399RK-CH4 Combustible Gas Transmitter

Infrared CH4 %Volume Detector

The infrared CH4 %Vol. detector consists of the detector housing body, detector housing
cap, cap gasket, and the plug-in sensor.

Detector Housing Body

Cap Gask et

Plug-In IR CH4
%Volume Sensor

Detector Housing Cap

Hydrophobic
Membrane

Figure 2: Infrared CH4 %Vol. Detector Component Location

Detector Housing Body

The detector housing body protects the electronic components within the housing. Use the
mounting threads at the top of the housing to screw the IR CH

NPT hub on the bottom of the junction box. 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.

The housing includes three sockets installed on a circuit board. These sockets accept the
plug-in sensor’s three pins to provide an electrical connection for the sensor. The circuit
board with the sockets conditions the sensor’s signal before the signal reaches the
amplifier.

Housing Cap & Cap Gasket

The housing cap screws onto the detector housing body. It retains the plug-in sensor a nd
protects it from damage. A foam gasket is installed inside the ho using cap that seals
against the sensor face. A hydrophobic membrane on the outside of the cap face keeps
water and particulates away from the sensor face behind the cap. Unscrew the detector
cap to access the plug-in sensor for maintenance or replacement. A cap gasket seals the
interface between the housing body and cap.

Plug-In CH

The plug-in se ns or is secured in the de t ect or assembly by the housing cap. The sensor pro­duces a millivolt output that corresponds to the detection range of the trans mitter.

Sensor

4

detector into the 3/4”

4

65-2399RK-CH4 Combus tible Ga s Tr a nsm itter • 3

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. The
detector drive current is factory set to 148 mA for the 65-2399RK-CH4. The amplifier
includes the detector terminal strip, controller terminal strip, span pot, zero pot, and test
points (see Figure 1).

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.

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 CH

detector to the amplifier.

NOTE: The IR CH4 %Vol. detector is factory-wired to the detector term in al strip. See

“Wiring the Methane Transmitter to a Controller” on page 6 for all wiring
procedures related to the transmitter.

%Vol.

4

Zero Pot

The zero pot is located in the upper left corner of the amplifier (see Figure 1). Use a small
flat blade screwdriver to turn the zero pot’s adjustment screw and adjust th e amplifier’s
zero (fresh air) output during the start-up and calibration procedures. Turn the adjust­ment 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 1). 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 1). 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 star t-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.

Junction Box

Use the junction box to install the transmitter at a mounting site that is remote from the
controller. The 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

4 • 65-2399RK-CH4 Combustible Gas Transmitter

Installation

controller. Use the cover on the f ront of the junction box to access the interior of the
junction box. The detector and amplifier are factory installed in the junction box. Three
spacers installed on the back of the junction box control the distance of the junction box
from a mounting surface and ensure that there is enough room to install a calibration cup
on the detector during calibration.

This section describes procedures to mount the methane trans mitter 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.

• 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.

3/4 NPT

Female

3.10

.75

.38

3.65

6.80 MAX
Rubber

Spacers,
3X

J-Box

IR CH4

%Volume

Detector

1 1/2-20Thread for Calibration Cup

Figure 3: Mounting the Methane Transmitter

65-2399RK-CH4 Combus tible Ga s Tr a nsm itter • 5

2. At the monitoring site you select, hang or mount th e jun c tion box with the detector
facing down (see Figure 3).

Wiring the Methane Transmitter to a Controller

WARN ING: Always verify that the power to the controller is off before you make

wiring connections.

1. Turn off the controller.

2. Turn off or unplug power to the controller.

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 sock et by
grasping the terminal strip and pulling. The socket for the detector strip and the plug
for the controller strip are 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. Use appropriate conduit fittings and construction
technique for the environmental rating of the junction box. The junction box is rated
NEMA 4X.

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 methane transmitter through one of the
conduit hubs at the controller housing. Use appropriate conduit fittings and
construction technique for the environmental rating of the controller. RKI controllers
are typically rated NEMA 4X.

CAUTION: Do not route power and transmitter wiring through the same controller conduit hub.

The power cabl e may disrupt the transmission o f the transmitte r signal to the
controller.

11. Connect the wires to the applicable detector/transmitter terminal strip at the
controller as shown in Figure 4.

6 • 65-2399RK-CH4 Combustible Gas Transmitter

Cable sheild

Amplifier

Black

+ 24 VDC
4 - 20 mA In (S)

- (DC Ground)

Controller

SPAN

ZERO

S

SIG/PWR

BGW

LEL

R

Green

Detector Wires

White

Red

J-Box

IR CH4 %Volume
Detector

Figure 4: Wiring the Methane 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.

65-2399RK-CH4 Combus tible Ga s Tr a nsm itter • 7

Start Up

This section describes procedures to start up the methane tran smitter 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 pow er to the controller.

4. Turn on the controller.

5. Verify that the controller is on and operating properly. Refer to the controller
operator’s ma nual.

NOTE: When first powered up, the transmitter will enter about a one minute period

when the 4-20 mA output is stab ilizing 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

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 junction box 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 calibration cup onto the bottom of the IR CH

5. Screw the regulator into the zero air calibration cylinder.

6. Use the calibration kit sample tubing to connect the regulator to the calibration cup.

7. Turn the regulator’s on/off knob counterclockwise to open it. Gas will begin to flow.

%Vol. detector.

4

8. Allow the gas to flow for one minute.

9. Verify a voltmeter reading of 100 mV (±2 mV).

10. If necessary, use a small flat-blade screwdriver to adjust the zero pot until th e

8 • 65-2399RK-CH4 Combustible Gas Transmitter

11. Turn the regulator’s on/off knob clockwise to close it.

12. Unscrew the calibration cup from the detector.

13. Unscrew the regulator from the zero air calibration cylinder. For convenience, leave

14. Store the components of the calibration kit in a safe and conve nient place.

15. Remove the voltmeter leads from the test points.

16. 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, monthly, and biannual
procedures.

voltmeter reading is 100 mV (±2 mV).

the sample tubing connected to the regulator and the calibration cup.

Daily

Verify a display reading of 0 %Vol. at the controller. Investiga te significant changes in the
display reading.

Monthly

This procedure describes a test to verify that the methane transmitter responds properly
to the target gas.

WARN IN G: The controller is not an active gas monitoring device during the response

test procedure.

NOTE: Performing a response test on the methane transmitter may cause alarms. Be sure

to put the controller into its calibration mode or disable external alarms before
performing this test.

NOTE: The following procedure assumes the use of a calibration kit which includes a

calibration gas cylinder, a 0.5 LPM fixed flow regulator with an on/off knob, a
calibration cup for the detector, and a length of sample tubing.

Preparing for the response test

1. Place the controller into its calibration mode or disable external alarms.

2. Verify that the controller display reading for the channel you are testing is 0 %Vol.
If the display reading is not 0 %Vol., set the zero reading of the transmitter as

described in “Start Up” on page 8, then continue this procedure.

3. Screw the regulator into the calibration cylinder.

4. Screw the calibration cup onto the bottom of the detector.

65-2399RK-CH4 Combus tible Ga s Tr a nsm itter • 9

5. Use the calibration kit sample tubing to connect the regulator to the calibration cup.

6. Set a voltmeter to measure in the millivolt (mV) range.

7. 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.

8. Use the following formula to determine the correct test points output for the test
sample.

Output (mV) = (calibrating sample/fullscale) X 400 + 100

For example, with a test sample of 50 %Vol. and a fullscale setting of 100 %Vol., the
correct output is 300 mV.

300 (mV) = (50/100) X 400 +100

Performing the response test

1. Turn the regulator’s on/off knob counterclockwise to open the regulator. Gas will
begin to flow.

2. Allow the gas to flow for one minute.

3. Verify that the reading is within ± 20% of the response reading you determined earlier.

NOTE: If the reading is not within ± 20% of the correct response reading, calibrate the

transmitter as described in “Calibration” on page 15 of this manual.

4. Turn the regulator’s on/off knob clockwise to close the regulator.

5. Unscrew the regulator from the calibration cylind er.

6. Unscrew the calibration cup from the detector.

NOTE: For convenience, leave the regulator and calibration cup connected by the

sample tubing.

7. Remove the voltmeter leads from the amplifier test points.

8. Reinstall the junction box cover.

9. When the controller display reading falls below th e alarm setpoints, return the
controller to normal operation.

10. Store the components of the calibration kit in a sa fe place.

Biannually

Calibrate the methane transmitter as described in “Calibration” on page 15 of this manual.

10 • 65-2399RK-CH4 Combustible Gas Transmitter

Troubleshooting

The troubleshooting guide describes symptoms, probable causes, and recommended
action for problems you may encounter with the methane trans mitter.

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 Methane Transmitter

Condition Symptom(s) Probable Causes Recommended Action

Fail Condition • Controller indicates a

Slow or No
Response/
Difficult or
Unable to
Calibrate

fail condition.

• Transmitter responds
slowly or does not
respond to response
test.

• 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 transmitter wiring
is disconnected or
misconnected.

• The wiring from the
detector to the
amplifier is
disconnected or
misconnected.

• The plug-in sensor is
not properly plugged
into the 3 socket
pattern in the detector
housing body.

• The transmitter’s zero
reading is low enough
to cause a fail
condition.

• The transmitter is
malfunctioning.

• The calibration cylinder
is low, out-dated, or
defective.

• The calibration gas is
not an appropriate
concentration.

• The membrane on the
detector housing cap is
blocked with dirt or
some other p a rticulate
matter.

• The transmitter is
malfunctioning.

1. Verify that the transmitter wiring is
correct and secure.

2. V erify that th e wiring from the detector
to the amplifier is correct and secure.

3. Confirm th at the plug-in sensor is
properly installed.

4. Perform a zero adjustment. A full
calibration is recommended.

5. If the fail condition continues, replace
the sensor as described later in this
section.

6. If the fail condition continues, contact
RKI for further instruction.

1. Verify that the calibration cylinder
contains an adequate supply of a
fresh test sample.

2. Verify that the calibration gas
concentration is appropriate for the
transmitter.

3. Check the face of the detector
housing cap and remove any
particulate contamination from the
hydrophobic membrane if necessary.
If membrane appears saturated with
contamination or damaged, replace
the membrane as described in the
next section.

4. If the calibration/response difficulties
continue, replace the sensor as
described later in this section.

5. If the calibration/response difficulties
continue, contact RKI for further
instruction.

65-2399RK-CH4 Combustible Gas Transmitter • 11

Replacing Components of the Methane Transmitter

This section includes a procedure to replace the hydrophobic membrane, a procedure to
replace the plug-in IR CH

detector assembly, and one to replace the amplifier. In most cases, it is not necessary to
replace the entire detector assembly.

Replacing the Hydrophobic Membrane

1. Turn off the controller.

2. Turn off or unplug incoming power to the controller.

3. Unscrew the detector housing cap from the detector housing body.

4. Gently pry up the edge of the white hydrophobic mem b rane with a small flat blade
screwdriver or a similar tool.

5. Peel off the hydrophobic membrane. It may be necessary to clean off the detector
housing cap face to remove any residue left from the adhesive backed membrane.

6. Install the new membrane in t he recess on the face of the detector housing cap.

7. Make sure the cap gasket is in place and screw the detector housing cap back onto the
detector housing body.

8. Turn on the pow e r to the controller.

%Vol. sensor, a procedure to replace the entire methane

4

9. 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 stab ilizing 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.

Replacing the Plug-In IR CH

%Volume Sensor

4

1. Turn off the controller.

2. Turn off or unplug power to the controller.

3. Unscrew the detector housing cap from the detector housing body. Make sure not to
lose the cap gasket.

4. Unplug and remove the plug-in IR CH

%Volume sensor.

4

5. Carefully plug the replacement sensor into the socket pattern that is located in the
detector housing.

6. Make sure the cap gasket is in place and screw the detector housing cap back onto the
detector housing body.

7. Turn on pow er to the controller.

8. Turn on the controller and place it into normal operation.

12 • 65-2399RK-CH4 Combustible Gas Transmitter

NOTE: When first powered up, the transmitter will enter about a one minute period

when the 4-20 mA output is stab ilizing 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 sensor to warm up for 5 minutes before you continue with the

next step.

9. Calibrate the transmitter as described in “Calibration” on page 15.

Replacing the IR CH

%Volume Detector

4

1. Turn off the controller.

2. Turn off or unplug power to the controller.

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. If necessary for en vironm e ntal conditions, apply thread sealant or teflon tape to
the hub and/or detector threads to seal them.

8. Connect the detector leads to the detector terminal strip as shown in Table 3 below
and Figure 4 on page 7 of this manual.

Table 3:Reconnecting the Methane

Detector to the Amplifier

Detector Lead Detector Terminal Strip

Red %Vol. “R”

White %Vol. “W”

Green %Vol. “G”

Black %Vol. “B”

9. Reinstall the detector terminal strip into its socket.

10. Tu rn on or plug in power to the controller.

11. Turn on the controller and place it into normal operation.

65-2399RK-CH4 Combustible Gas Transmitter • 13

NOTE: When first powered up, the transmitter will enter about a one minute period

when the 4-20 mA output is stab ilizing 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 co ntinue with

the next step.

12. Calibrate the transmitter as described in “Calibration” on page 15 of this manual.

Replacing the Amplifier

1. Turn off the controller.

2. Turn off or unplug power to the controller.

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.

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 in to the junction box with the screw, lock washer, and flat
washer you removed in Step 5 above.

9. Install the detector and controller terminals strips into their sockets on the new
amplifier as shown in Figure 4 on page 7 of this manual. If controller leads or detector
leads were removed d uring this procedure, refer to Table 4 and Table 5 b elow.

Table 4:Reconnecting the Amplifier

to the Controller

Amplifier Controller

Te rminal Strip

PWR/SIG “-” - (DC -)
PWR/SIG “S” S (4 - 20 mA In)
PWR/SIG “+” + 24V

Table 5:Reconnecting the CH4 %Vol.

Detector to the Amplifier

Controller

Transm itte r Terminal

Strip (typical)

Amplifier Detector

T erminal Strip

DETECTOR “R” RED

14 • 65-2399RK-CH4 Combustible Gas Transmitter

Detector Lead

Table 5:Reconnecting the CH4 %Vol.

Detector to the Amplifier

Amplifier Detector

T erminal Strip

DETECTOR “W” WHT

DETECTOR “G” GREEN
DETECTOR “B” BLK

Detector Lead

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 pow er 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 stab ilizing 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 15 of this manual.

Calibration Frequency

Although there is no particular calibration frequency that is correct for all applications, a
calibration fre quency of every 6 months is adequat e for most infrared meth ane transmitte r
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.

Calibration

This section describes how to calibrate the methane transmitter. It includes procedures to
prepare for calibration, set the zero reading, set the response rea d ing, and return to
normal operation.

W ARNING: The controller is not an active gas monitoring device during the calibration

procedure.

65-2399RK-CH4 Combustible Gas Transmitter • 15

NOTE: The following procedure assumes the use of a calibration kit which includes a

calibration gas cylinder, a 0.5 LPM fixed flow regulator with an on/off knob, a
calibration cup for the detector, and a short piece of sample tubing to connect the
regulator to the calibration cup.

Prepari ng for Ca libration

1. Unscrew and remove the junction box cover.

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. Use the following formula to determine the correct test points output for the
calibrating sample.

Output (mV) = (calibrating sample/fullscale) X 400 + 100

For example, with a calibrating sample of 50 %Vol. and a fullscale setting of
100 %Vol., the correct output is 300 mV.

300(mV) = (50/100) X 400 +100

5. Screw the calibration cup onto the detector housing.

6. Place the controller into its calibration mode or disable external alarms.

NOTE: Calibrating the methane transmitter may cause alarms. Be sure to put the

controller into its calibration mode or disable external alarms before continuing.

Setting the Zero Reading

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.

1. Screw the regulator into the zero air calibration cylinder.

2. Use the calibration kit sample tubing to connect the regulator to the calibration cup.

3. Turn the regulator’s on/off knob counterclockwise to open the regulator.

4. Allow the gas to flow for one minute and verify a reading of 100 mV (±2 mV). If
necessary, use the zero pot on the amplifier to adjust the reading to 100 mV (±2 mV).

5. Turn the regulator’s on/off knob clockwise to close the regulator.

6. Unscrew the regulator from the zero air calibration cylinder.

7. Leave the sample tubing connected to the regulator and the calibration cup.

Setting the Response Reading

1. Screw the regulator into the calibration cylinder. Verify that the calibration gas is
representative of the transmitter’s target gas.

2. Turn the regulator’s on/off knob counterclockwise to open the regulator.

3. Allow the calibration gas to flow for one minute and verify that the reading matches
the response reading (±2 mV) you determined ea rlier. If necessary , use the span pot on
the amplifier to adjust the reading to match the correct response reading.

16 • 65-2399RK-CH4 Combustible Gas Transmitter

Parts List

4. Turn the regulator’s on/off knob clockwise to close the regulator.

5. Unscrew the regulator from the calibration cylind er.

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

sample tubing.

3. Secure the junction box cover to the junction box.

4. When the controller display reading falls below th e alarm setpoints, return the
controller to normal operation.

5. Verify that the co ntroller display reading decreases and stabilizes at 0 % Vol.

6. Store the components of the calibration kit in a safe and convenient place.

Table 6 lists replacement parts and accessories for the methane transmitter.

Table 6:Parts List

Part Number Description

06-1248RK Sample tubing (3/16 in. x 5/16 in.; specify length when ordering)
18-0400RK-01 Junction box with spacers
33-0157RK Hydrophobic disk membr ane for detect or cap
57-1053RK Amplifier with gasket (specify detector part number when ordering)
61-0199RK-CH4 Infrared CH

61-5041RK-CH4 Infrared CH
65-2399RK-CH4 Methane transmitter (includes detector, junction box, and amplifier)

71-0201RK
81-0013RK-01 Steel calibration cylinder, 50% Volume methane in nitrogen, 34-liter
81-0076RK-01 Steel calibration cylinder, zero emission air, 34-liter
81-1050RK Regulator, 0.5 liter/minute; with pressure gauge and flow control knob, for 17 liter and

81-1103RK Calibration cup

65-2399RK-CH4 Methane Transmitter Operator’s Manual (this documen t)

34 liter steel calibration cylinders

%Vol. detector

4

replacement plug-in sensor

4

82-0006RK Pot adjust screwdriver, for calibration

65-2399RK-CH4 Combustible Gas Transmitter • 17