Read and understand this instruction manual before operating
detector . Improper use of the dete ctor 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.
T ypical calibration frequencies for most applications are b etween
3 and 6 months, but can be required more often or less often
based on your usage.
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 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 no r mal service, 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 responsible for r emoval 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 cartridgesd) Batteries
b) Pump diaphragms and valvese) 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 as su m e i ndemnificatio n fo r any accident o r damage caused by the operat io n of
this gas monitor, and our warranty is limited to the replacement of parts or our complete
goods.
This manual describes the 65-2497RK oxygen detector. This manual also describes how to
install, start up, maintain, and calibrate the oxygen detector when used with a gas
monitoring controller. A parts list at the end of this manual lists replacement parts and
accessories for the oxygen detector.
The 65-2497RK oxygen detector includes the 65-2494RK oxygen detector and a junction
box. This manu al may also be used for the 65-2494RK oxygen detector whic h does not
include a junction box and is normally mounted in one of a controller’s conduit hubs. If
you are using a 65-2494RK oxygen detector, disregard all references to the junction box
and junction box terminal strip.
Specifications
WARNING: Do not use this product in a manner not specified in this instruction
Table 1 lists specifications for the 65-2494RK and 65-2497RK oxygen detectors.
manual.
Table 1: Specifications
Target GasOxygen (O
Sampling MethodDiffusion
Detection Range0-25% oxygen
Response Time90% in 30 seconds
Accuracy± 0.5% O
Operating Temperature-4°F to 113°F (-20°C to 45°C)
WARNING: When using the 65-2494RK/65-2497RK, you must follow the instructions
and warnings in this manual to assure proper and safe operation of the
65-2494RK/65-2497RK and to minimize the risk of personal injury. Be sure
to maintain and periodically calibrate the 65-2494RK/65-2497RK as
described in this manual.
This section describes the components of the 65-2494RK and 65-2497RK detectors. The
65-2497RK in cludes the 65-2494RK oxygen detector and a junction box. A two point
terminal strip is pro vid ed insid e the jun ction box fo r detector co nnecti ons. The 65 -2494R K
does not include a junction box. Figure 1 below shows the components of the 65-2497RK.
3/4 NPT Conduit Hub
WhiteGreen
Figure 1: 65-2497RK Component Location
65-2494RK Oxygen De tector
The 65-2494RK oxygen detector consists of the detector housing body, detector housing
cap, cap gasket, and the plug-in sensor.
The detector housing body protects the electronic components within the housing. Use the
mounting threads at the top of the housing to screw the oxygen detector into a 3/4” NPT
hub. Two wires extend from the top of the detector housing body. Use these wires to
connect the detector to a controller. One of the wires is white and one of the wires is green.
The housing body includes two sockets installed on a circuit board. These sockets accept
the plug-in sensor’s two pins to provide an electrical connection for the sensor . The cir cuit
board with the sockets conditions the sensor’s signal before the signal reaches the
controller.
Housing Cap & Cap Gasket
The housing cap screws onto the detector housing. It retains the plug-in sensor and
protects it from damage. A foam gasket inside the housing cap seals against the face of the
sensor when the cap is screwed on the housing body. 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 and cap.
Plug-in Sensor
The plug-in sensor is secured in the detector assembly by the housing ca p. Through a
series of chemical and electrical reactions, the sensor produces an electrical output that
corresponds to the detection range of the detector. The sensing element used is a capillary
type that is not susceptible to output changes with changes in atmospheric pressure.
Installation
Junction Box
Use the junction box to install the oxygen detector at a mounting site that is remote from a
controller and to protect the detector wiring connections. Two conduit hubs allow you to
mount the detector to the junction box and connect the wiring from the detector to a
controller. 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. A terminal block within the junction
box facilitates the wiring connections. A cover on the front of the junction box allows
access to the interior of the junction box.
This section describes procedures to mount the oxygen detector in the monitoring
environment and wire the detector to a controller.
Mounting the Oxygen Detector
NOTE: If you are installing a 65-2494RK, it does not include a junction box and is usually
factory installed in one of a controller’s conduit hubs or may be field installed
using the 3/4” NPT threads on the end with the wires. The 65-2497RK includes a
junction box as shown in Figure 3 below.
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 detector is not likely to be bumped or disturbed. Make sur e
there is sufficient room to perform start-up, maintenance, and calibration
procedures.
2. At the mounting site you select, hang or mount the junction box wit h the detector
facing down (see Figure 3).
Wiring the Oxygen Detector to a Controller
WARNING: Always verify that 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. If the detector is mou nted remotely from a controller using the ju nction box, proceed
to step 4.
If the detector is mounted directly to a controller, it is normally factory wired. Confirm
that the detector’s white and green wires are connected to the appropriate controller
detector terminals and skip to “Start Up” on page 6. See Figure 4, the controller
operator’s manual, and the controller’s detector head specification sheet for the
65-2494RK detector for the wiring connections.
4. Remove the junction box cover.
5. Guide a two-conductor, shielded cable or two wires in conduit through the unused
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.
6. Connect the two wires to the detector using the terminal block.
CAUTION: If using shielded cable, leave the drain wire insulated and disconnected at the
detector. You will connect the opposite end of the cable’s drain wire at the controller.
7. Secure the junction box cover to the junction box.
8. Route the cable or wires leading from the oxygen detector 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 detector wiring through the same conduit hub. The po wer
cable may disrupt the transmission of the detector si gnal to the controller.
9. Connect the wires to the applicable controller terminal strip. See the controller
operator’s manual and the controller’s detector head specification sheet for the
65-2497RK detector.
Controller Oxygen
Detector Terminals
Controller Housing
Green (-)
Whi te ( +)
Shielded Cable
White
J-Box
Green
Oxygen detector assembly
Figure 4: Wiring the Oxygen Detector to a Controller
10. If using shielded cable, connect the cable’s drain wire to an available chassis ground at
the controller. RKI controllers typically have a ground stud that is a convenient
grounding location.
This section describes procedures to start up the oxygen detector and place the detector
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 or plug in the incoming power, then turn on the controller.
4. Verify that the controller is on and operating properly. Refer to the controller
operator’s manu al.
CAUTION: Allow the detector to warm up for 5 minutes before you continue with the next
section, “Setting the Fresh Air Reading”.
Setting the Fresh Air Reading
CAUTION: If you suspect the monitoring environment is not a fresh air environment, use the
zero air calibration cylinder to introduce “fresh air” to the detector and verify an
accurate fresh air reading.
1. Verify that the oxygen detector is in a fresh air environment (environment known to
be free of toxic and combustible gases, and of normal oxygen content, 20.9%).
2. Verify a reading of 20.9% oxygen at the controller.
3. Perform a fresh air adjustment operation at the controller. See the controller
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 oxygen detector. It includes daily, monthly, and quarterly procedures.
Daily
Verify a display reading of 20.9% oxygen at the controller. Investigate significant changes
in the display reading.
Monthly
This procedure describes a test to verify that the oxygen detector responds properly to
oxygen deficiency.
If the display reading is 20.9% oxygen, start up is complete. The oxygen detector is in
normal operation. If the display reading is not 20.9% oxygen, continue with step 3.
WARNING: The controller is not an active gas monitoring device during the response
test procedure.
NOTE: Performing a respon se test on the oxygen detector may cause alarms. Be sure to
put the controller into its calibration program or disable external alarms before
performing this test.
1. Place the controller into its calibration program or disable external alarms.
2. Verify that the controller display reading is 20.9% oxygen.
If the display reading is not 20.9% oxygen, set the fresh air reading, then continue this
procedure. See the controller operator’s manual for instructions to set the fresh air
reading.
3. Exhale into the bottom of the oxygen detector housing.
4. Stop exha ling into the bottom of the detector, then verify that the reading on the
controller display decreased from the normal reading of 20.9% oxygen.
NOTE: If the reading does not decrease, calibrate the detector as described in
“Calibration” on page 11.
5. When the display reading rises above the decreasing alarm setpoint, return the
controller to normal operation.
Quarterly
Calibrate the detector as described in “Calibration” on page 11. See the calibration
frequency discussion in “Calibration Frequency” on page 10 to determine if a qua r terly
calibration schedule fits your needs.
Slow or No
Response/
Difficult or
Unable to
Calibrate
fail condition.
• Detector responds
slowly or does not
respond to response
test.
• Unable to accurately
set the fresh air or
zero reading during
calibration.
• Detector requires
frequent calibration.
Note: Under “normal”
circumstances, the
transmitter requires
calibration once every 3
months.
Some applications
may require a more
frequent calibration
schedule.
• The detector wiring is
disconnect ed or
misconnected.
• The plug-in sensor is
not properly plugged
into the socket pattern
in the detector ho using
body.
• The detector’s zero
reading is low enough
to cause a fail
condition.
• The detector is
malfunctioning.
• The calibration cylinder
is low, out-dated, or
defective.
• The calibration gas is
not an appr opriate
concentration.
• The membrane on the
detector housing cap is
blocked with dirt or
some other particulate
contamination.
• The detector is
malfunctioning.
1. Verify that the detector wiring is
correct and secure.
2. Confirm that the plug-in sensor is
installed properl y.
3. Perform a fresh air adjustment. A full
calibration is recommended.
4. If the fail condition continues, replace
the plug-in sensor as described later
in this section.
5. 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. Zero emission air (20.9%
oxygen) is normally used for a fresh
air adjustment if the environment is
suspect and 100% nitrogen (0%
oxygen) is normally used for a zero
adjustment.
3. Check the sensor face for dirt. Clean
if necessary.
4. Check the face of the detector
housing cap and remove any
particulate contamination from the
hydrophobic membrane if necessary.
If the membrane appears saturated
with contamination or damaged,
replace the membrane as described
in the next section.
5. If the calibration/response difficulties
continue, replace the plug-in sensor
as described later in this section.
6. If the calibration/response difficulties
continue, contact RKI for further
instruction.
This section includes a procedure to replace the plug-in oxygen sensor, one to replace the
hydrophobic membrane, and one to replace the entire oxygen detector assembly. In most
cases, it is not necessary to replace the entire detector assembly.
Replacing the Plug-in Oxygen Sensor
CAUTION: The plug-in sensor contains electrolyte which is an irritant. Do not disassemble the
sensor when replacing it with a new one. If sensor electrolyte comes in contact with
your skin, wash affected area thoroughly with soap and water.
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.
4.Unplug and remove the old oxygen sensor.
5. Carefully plug the replacement sensor into the sockets located in the detector housing
body.
6. Make sure the cap gasket is in place and screw the detector housing cap back onto the
detector housing body.
7. Turn on power to the controller.
8. Turn on the controller and place into normal operation.
CAUTION: Allow the replacement sensor to warm up for 5 minutes before you continue with the
next step.
9. Ca librate the detector as described in “Calibration” on page 11.
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 membrane 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 the 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.
NOTE: In most cases, it is only necessary to replace the plug-in sens or.
1.Turn off the controller.
2. Turn off or unplug incoming power to the controller.
3. If the detector is installed directly on a controller, open the controller door.
If the detector is installed remotely from a controller in a junction box, remove the
junction box cover.
4. If the detector is installed directly on a controller, disconnect the detector leads from
the detector terminal strip in the controller. Note the position of the color-coded leads
as you remove them.
If the detector is installed remotely from a controller in a junction box, disconnect the
detector leads from the terminal block in the junction box. Note the position of the
color-coded leads as you remove them.
5. Unscrew the detector from the controller conduit hub or junction box conduit hub.
6. Guide the detector leads of the replacement detector through the controller conduit
hub or junction box conduit hub, then screw the mounting threads of the detector into
the hub. If necessary for environmental conditions, apply thread sealant or teflon tape
to the hub and/or detector threads to seal them.
7. If the detector is installed directly on a controller, connect the detector leads to the
appropriate detector terminal strip terminals. See Figure 4 on page 5 for wiring to a
generic controller. See the controller operator’s manual and the controller’s detecto r
head specification sheet for the 65-2494RK detector for wiring specific to your
controller.
If the detector is installed remotely from a controller in a junction box, connect the
detector leads to the terminal block the same way the old detector was wired (see
Figure 4 on page 5). See the controller operator’s manual and the controller’s detector
head specification sheet for the 65-2497RK detector to verify the connections to the
controller are correct.
8. If the detector is installed remotely from a controller in a junction box, reinstall the
junction box cover.
9. Turn on or plug in power to the controller.
10. Turn on the controller and place into normal operation.
CAUTION: Allow the replacement detector to warm up for 5 minutes before you continue with
the next step.
11. Calibrate the replacement detector as described in “Calibration” on page 11.
Calibration Frequency
Although there is no particular calibration frequency that is correct for all applications, a
calibration frequency of every 3 months is adequate for most oxygen detector
applications. Unless experience in a particular application dictates otherwise, RKI
Instruments, Inc. recommends a calibration frequency of every 3 months for the oxygen
detector.
If an application is not very demanding, for example detection in a clean, temperature
controlled environment, and calibration adjustments are minimal at calibration, then a
calibration frequency of every 6 months is adequate.
If an application is very demanding, for example if the environment is not well controlled,
then more frequent calibration than every 3 months may be necessary.
This section describes how to calibrate the oxygen detector. It includes procedures to
prepare for calibration, set the fresh air r eading, set the zero r eading, and return to normal
operation. It describes calibration 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.
Prepari ng for Ca libra t ion
1. Screw the calibration cup onto the bo ttom of the oxygen detector.
2. S c rew the regulator into the zero air calibration cylinder. Make sure the regulator is
off. It is off when the on/off knob is turned all the way clockwise.
3. Use the sample tubing to connect the regulator to the calibration cup.
NOTE: If you can verify that the oxygen detector is in a fresh air environment, you do
not need to apply zero air to the detector before adjusting the fresh air reading.
4. Put the controller into its calibration program. See the controller operator’s manual
for instructions to enter the calibration program.
Setting the Fresh Air Reading
1. Follow the instructions in the controller operator’s manual for setting the fresh air
reading.
2. When the instructions call for applying zero air to the detector, turn the regulator’s
on/off knob counterclockwise to open it. Gas will begin to flow.
3. Allow the gas to flow for two minutes.
4. Set the fresh air reading according to the controller operator’s manual.
5. Turn the regulator ’s on/off knob clockwise to close it.
6. Unscrew the regulator from the zero air calibration cylinder . Leave the sample tubing
connected to the regulator and the calibration cup.
NOTE: Depending on the size of your zero air cylinder , it is possible that you will have a
different regulator for the zero air cylinder and the nitrogen gas cylinder. If
necessary to fit the nitrogen gas cylinder, change the regulator.
Setting the Zero Reading
1. S c rew the regulator into the 100% nitrogen calibration cylinder. Make sure the
regulator is off. It is off when the on/off knob is turned all the way clockwise.
2. Follow the directions in the controller operator’s manual for setting the zero reading.
3. When the directions call for exposing the detector to gas, turn the regulator’s on/off
knob counterclockwise to open it. Gas will begin to flow.
4. Allow the gas to flow to the detector for 2 minutes.
5. Set the zero reading according to the controller operator’s manual.
6. After setting the zero reading, turn the regulator’s on/off knob clockwise to turn it
off.
7. Unscrew the regulator from the cylinder.
8. Unscrew the calibration cup from the oxygen detector. Make sure that you do not
loosen the detector housing cap when you unscrew the calibration cup.
NOTE: For convenience, leave the regulator and calibration cup connected by the
sample tubing.
9. Allow about 45 seconds for the gas reading to increase above the decreasing alarm
point and then return the controller to normal operation.
NOTE: If you do not allow the gas reading to increase above the decreasing alarm point,
then unwanted alarms may occur.
10. Verify that the controller display reading increases and stabilizes at 20 . 9% oxygen.
11. Store the components of the calibration kit in a safe and convenient place.