RKI Instruments 65-2425 User manual

RKI Instruments, Inc.
www.rkiinstruments.com
65-2425
Hydrogen Cyanide Detector
Operator’s Manual
Part Number: 71-0623
Revision: P1
Released: 1/17/23

2• 65-2425 Hydrogen Cyanide Detector Operator’s Manual
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.

65-2425 Hydrogen Cyanide Detector Operator’s Manual • 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:
• Absorbent cartridges
•Fuses
• Pump diaphragms and valves
•Batteries
• Filter elements
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 APARTICULAR PURPOSE. INNO
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.

4• 65-2425 Hydrogen Cyanide Detector Operator’s Manual
Table of Contents
Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Detector Housing, Housing Cap, & Cap Gasket . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Rubber Boot and Spacer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Sensor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Mounting the HCN Detector. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Wiring the HCN Detector to a Controller. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Startup. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Introducing Incoming Power . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Setting the Zero Signal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Preventive Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Replacing Components of the HCN Detector. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Calibration Frequency . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Calibration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Preparing for Calibration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Setting the Zero Reading . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Setting the Response Reading. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Returning to Normal Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Parts List . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

65-2425 Hydrogen Cyanide Detector Operator’s Manual Overview • 5
Overview
This manual describes the 65-2425 hydrogen cyanide (HCN) detector. This manual also describes
how to install, start up, maintain, and calibrate the detector 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
HCN detector.
Specifications
WARNING: Do not use this product in a manner not specified in this instruction manual.
Table 1 lists specifications for the HCN detector.
NOTE: The following symbol on the detector label is a caution to the user to refer to this
documentation for installation and operation instructions:
Table 1: Specifications
Tar get G as Hydrogen cyanide (HCN)
Area Classification* Explosionproof for Class I, Groups B, C, and D
Temperature Code T6
Installation Category
Installation Category 1. Signal level, special equipment or
parts of equipment, telecommunication, electronic, etc., with
smaller transient overvoltages than Installation Category
(Overvoltage Category) II (ref. IEC 664).
Sampling Method Diffusion
HCN Detector Signal
Output
0.3 mA at 0 ppm HCN nominal
2.5 mA at 15.0 ppm HCN nominal
Detection Range 0 to 15.0 ppm (parts per million)
Accuracy ± 10% of reading or ± 5% of full scale (whichever is greater)
Response Time 90% in 30 seconds
Operating
Temperature
-4°F to 104°F (-20°C to 40°C)
* The area classification only applies if the detector is installed using a junction box with an
internal volume less than or equal to 69 cubic inches and rated explosion proof for Class I,
Groups B, C, and D. The detector is not explosion proof if it is installed in a non-explosion proof
enclosure, such as in a conduit hub of a controller like the Beacon 200 or Beacon 800.
!

6• Description 65-2425 Hydrogen Cyanide Detector Operator’s Manual
WARNING: When using the 65-2425, you must follow the instructions and warnings in this
manual to assure proper and safe operation of the 65-2425 and to minimize the
risk of personal injury. Be sure to maintain and periodically calibrate the 65-
2425 as described in this manual.
Description
This section describes the components of the HCN detector. The detector consists of the detector
housing body, housing cap, cap gasket, rubber boot, spacer, and the HCN sensor.
Figure 1: HCN Detector Component Location
Detector Housing Body, Housing Cap, & Cap Gasket
The detector housing body protects the sensing components within the housing. Use the mounting
threads at the top of the housing to screw the HCN detector into a 3/4 NPT hub. 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. A cap gasket seals the interface
between the housing and cap. A flame arrestor guard is permanently bonded to the cap.
Two wires extend from the top of the detector housing. Use these wires to connect the HCN
detector to a controller. 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 controller.
Rubber Boot
Flame
Arrestor
Guard
Detector
Housing Cap
Spacer
VersaporR Membrane
Detector Housing Body
Cap Gasket
HCN Plug-in Sensor

65-2425 Hydrogen Cyanide Detector Operator’s Manual Installation • 7
Rubber Boot and Spacer
A rubber boot and spacer are installed between the detector housing cap and the sensor. They help
ensure that the detector remains plugged into the detector housing body.
Plug-In Sensor
The sensor is secured within the sensor housing by four pins. Through a series of chemical and
electrical reactions, the sensor produces an electrical output that is proportional to the detection
range of the detector. A VersaporR membrane is installed on the sensor face for added protection
from water and particulate contaminants.
Installation
NOTE: Normally, the HCN detector is shipped already installed in one of the bottom conduit
hubs of a controller and factory wired to the controller. If your detector is already
installed in a controller, use this section for reference only.
This section describes procedures to mount the HCN detector in the monitoring environment and
wire the detector to a controller.
Mounting the HCN Detector
1. Whether you will mount the detector directly to a controller or to a junction box, 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 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
detector at approximately breathing level.

8• Installation 65-2425 Hydrogen Cyanide Detector Operator’s Manual
Figure 2: Outline & Mounting Dimensions
2. At the monitoring site, mount the detector in one of the following two ways:
• Screw the detector’s 3/4 NPT mounting thread into an empty conduit hub on a controller.
OR
• Screw the detector’s 3/4 NPT mounting thread into an appropriately rated junction box.
CAUTION: Mount the HCN detector with the detector facing down (see Figure 2).
NOTE: If the mounting site requires the detector installation to be explosion proof,
you must install the detector in a junction box with an internal volume less
than or equal to 69 cubic inches and rated explosion proof for Class I,
Groups B, C, and D.
Wiring the HCN Detector to a Controller
WARNING: Always verify that the power source is OFF before you make wiring connections.
1. Turn off the controller.
2. Turn off or unplug power to the controller.
Shrink Tubing
3/4 NPT
1.62 Flats for
Wrench
1-1/2-20 ForCalibration Cup
9.75 Ref
2.25 Ref
Ø 1.75
0.75
3.59

65-2425 Hydrogen Cyanide Detector Operator’s Manual Installation • 9
3. If the detector is mounted remotely from a controller using an explosion proof junction box,
proceed to step 4.
If the detector is mounted directly to a controller, connect the detector’s red and black
wires to the appropriate controller detector terminals and skip to the Startup Section.
4. Remove the junction box cover.
WARNING: To maintain the explosion proof classification of the HCN detector/junction
box combination, a conduit seal must be used within 2 inches of the junction
box conduit hub used for wiring to the controller.
5. Guide a two-conductor, shielded cable or two wires in conduit through an unused conduit hub
of the junction box.
6. Connect the two wires to the detector using an appropriate 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 HCN detector through one of the conduit hubs at the
controller housing.
CAUTION: Do not route power and detector wiring through the same conduit hub.
The power cable may disrupt the transmission of the detector signal to
the controller.

10 • Installation 65-2425 Hydrogen Cyanide Detector Operator’s Manual
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 HCN detector.
Figure 3: Wiring the HCN Detector to a Controller
10. 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.
11. Reinstall the junction box cover.
Controller HCN Detector Terminals
(typical terminal designation shown) S
+
RedBlack