RKI Instruments GD-K7D2 User manual

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Model GD-K7D2 (24 VDC)
Sample Draw Detector
Operator’s Manual
Part Number: 71-0078RK
Revision: A
Released: 3/1/11

Model GD-K7D2 (24 VDC) Sample Draw 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.

Model GD-K7D2 (24 VDC) Sample Draw 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 the 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. Parts must be returned to RKI
Instruments, Inc. for repair or replacement. 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 instruction 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 only 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. Warranty covers parts and labor performed at RKI Instruments, Inc. only, and does
not cover field labor or shipment of parts back to RKI.
a) Pump diaphragms and valves c) Batteries
b) Fuses d) Filter elements

Model GD-K7D2 (24 VDC) Sample Draw Transmitter
Table of Contents
Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Specifications. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Cover. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Detection Unit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Installation Bracket. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Disassembling the GD-K7D2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Mounting the GD-K7D2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Connecting Sample Lines to the GD-K7D2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Wiring the GD-K7D2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Assembling the GD-K7D2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Startup. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Introducing Incoming Power . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Setting the Zero Signal. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Normal Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Low Flow Alarm. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Maintenance. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Preventive Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Storing the GD-K7D2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Replacing Components of the GD-K7D2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Calibration Frequency . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
Calibration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
Preparing for Calibration. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
Setting the Zero Reading . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
Setting the Response Reading. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
Parts List . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22

Model GD-K7D2 (24 VDC) Sample Draw Transmitter • 1
Overview
This manual describes the 24 VDC version of the Model GD-K7D2 sample draw 4 - 20 mA
transmitter detector head. This manual also describes how to install, start up, maintain,
and calibrate the GD-K7D2 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 GD-K7D2.
Specifications
Table 1 lists specifications for the 24 VDC version of the GD-K7D2.
WARNING: When using the GD-K7D2, you must follow the instructions and warnings
in this manual to assure proper and safe operation of the GD-K7D2 and to
minimize the risk of personal injury. Be sure to maintain and periodically
calibrate the GD-K7D2 as described in this manual.
Table 1: Specifications
Target Gas & Detector Range Refer to the RKI Instruments Inc. List of Detectable Gasses
Area Classification Indoor, non-hazardous locations
Sampling Method Sample-draw
Input Power 24 VDC
Signal Output 4 to 20 mA
Response Time 90% in 60 seconds
Accuracy ± 10% of reading or ± 5% of full scale (whichever is greater)
Flow Rate Approximately 0.5 liters/minute
Recommended Sample Tubing 4 mm I.D. x 6 mm O.D. Teflon PTFE
Recommended Sample Tubing Length See Table 2 in the Installation section on p. 10

2 • Model GD-K7D2 (24 VDC) Sample Draw Transmitter
Description
This section describes the components of the GD-K7D2. The GD-K7D2 consists of three
separate sections: the cover, the detection unit, and the installation bracket. The detection
unit (front section) includes the flow system and gas detection components. The L-shaped
installation bracket (rear section) includes installation components including a terminal
strip, tube fittings and a card edge connector socket.
The detection unit and installation bracket are secured together by a captive screw located
in the bottom right of the detection unit. The detection unit’s main circuit board plugs into
the socket on the installation bracket. The socket is above the terminal strip.
Figure 1: Sections of the GD-K7D2
A hydrophobic sample filter is also provided with the GD-K7D2 for installation near the
sample in fitting. The filter scrubs particulates out of the sample stream and keeps water
and many other liquids from entering the GD-K7D2 flow system.
Cover
The painted steel cover slides over both the detection unit and installation bracket. It is
radio frequency (RF)- and dust-resistant. A thumbscrew on the front of the cover near the
bottom secures the cover to the installation bracket (see Figure 1). The cover includes a
label on the front that indicates the target gas and detection range of the GD-K7D2.
Cover
Detection Unit
Installation Bracket

Model GD-K7D2 (24 VDC) Sample Draw Transmitter • 3
The flow light and flowmeter are visible through the cover. The flow rate potentiometer
(pot) is accessible through the cover.
Figure 2: GD-K7D2 Cover Components
Detection Unit
The detection unit includes the main circuit board, flowmeter, gas sensor, amplifier,
pump, and lithium battery pack.
Figure 3: Detection Unit Component Location
GAS DETECTOR MODEL GD-K7D
FLOWADJ.
Flowmeter
Flow light
Flow rate
potentiometer
ID card holder
Gas name
card holder
Thumbscrew
TP1 (+)
TP2 (+) mA
Output
Factory Adjust Pot
Gain Pot
(Factory Adjust)
Span Pot
Zero Pot
Low Flow
Sensor
Flowmeter
Factory Adjust Pot
ON/OFF Switch
Flow Rate Pot
Flow Light Lithium Battery
Pack
Gas Sensor
Sample Adapter
Sensor Retaining
Clamp
Main Circuit Board
Fuse
Captive Retaining Screw
Amplifier
Pump
Bracket
Pump

4 • Model GD-K7D2 (24 VDC) Sample Draw Transmitter
Main Circuit Board
The main circuit board includes the flow light, flow rate pot, ON/OFF switch and fuse.
The end of the board at the rear of the detection unit plugs into a socket on the installation
bracket.
Flow light
The flow light is at the top left corner of the detection unit (see Figure 2 and 3). The green
flow light is on when the GD-K7D2’s flow rate is at an acceptable flow rate. If the flow rate
drops below or rises above the acceptable flow rate, the flow light turns off.
Flow rate pot
The flow rate pot is to the right of the flow light (see Figure 2 and 3). You can adjust the
GD-K7D2’s flow rate with the flow rate pot. The pot is accessible through a hole in the
cover.
ON/OFF switch
The ON/OFF switch is to the right of the flow rate pot (see Figure 3). The On/Off switch
turns the GD-K7D2 on and off. The switch is in the ON position when the toggle switch is
in the right position.
Fuse
A 2 amp, 5 mm x 20 mm fuse is located on the middle left of the main board. It is
accessible by removing four screws that retain a metal cover over the main board.
Flowmeter
The flowmeter is below the flow light (see Figure 2 and 3). A ball in the flowmeter column
indicates the flow rate of the GD-K7D2. Two horizontal lines on the flowmeter mark the
acceptable flow rate for the GD-K7D2. Use the flow rate pot to keep the flowmeter ball
between the two lines. A flow sensor at the bottom of the flowmeter senses when the
flowmeter ball is low enough to be at the bottom of the flowmeter and initiates a low flow
alarm.
Gas Sensor
The gas sensor is below and to the right of the flowmeter (see Figure 3). Through a series
of electrical and chemical reactions, the gas sensor produces an electrical current that is
proportional to the detection range of the target gas in the test sample. Electrodes within
the gas sensor housing are surrounded by liquid electrolyte. The chemical and electrical
reactions are facilitated by the electrolyte.
A sample adapter is attached to the front of the sensor. It directs the sample over a gas
permeable membrane on the front of the sensor and into the sensor.
Amplifier
The amplifier is to the right of the sensor (see Figure 3). The amplifier converts the output
of the sensor to a 4 to 20 mA signal (that is proportional to the detection range of the GD-
K7D2) and transmits the signal to a controller. The amplifier includes the span pot, zero
pot, gain pot, and output check pins.
Span pot
The span pot is at the top of the amplifier. Use the span pot to adjust the GD-K7D2’s
response output during the calibration procedure.
Zero pot
The zero pot is below the span pot. Use the zero pot to adjust the GD-K7D2’s fresh air

Model GD-K7D2 (24 VDC) Sample Draw Transmitter • 5
output during start-up and calibration procedures.
Gain pot
The gain pot is below the zero pot. It is used to make coarse span adjustments. The gain
pot is factory set and for adjustment by a field service technician only.
Another factory adjust pot is located below the gain pot. Do not adjust this pot.
Output check pins
Two output check pins [marked 1 (+) and 2 (-)] are below the pots. Use the output check
pins to read the signal output of the GD-K7D2 with a milliampmeter during the start-up
and calibration procedures.
Pump
The pump is behind the sensor. The pump pulls the test sample into the GD-K7D2. The
pump operates on AC voltage that is generated by the GD-K7D2 from the 24 VDC input
power.
Lithium Battery Pack
A 3.6 volt lithium battery pack is above the pump on the right side of the GD-K7D2. The
lithium battery pack maintains a bias voltage on the gas sensor when the GD-K7D2 is not
receiving incoming power, such as during shipment or storage. If the GD-K7D2 is off
power for an extended period and the lithium battery pack is dead, the gas sensor
operation will be affected when the GD-K7D2 is started up. See Storing the GD-K7D2 in
the Maintenance section for battery pack replacement recommendations.
Installation Bracket
The L-shaped installation bracket facilitates mounting and wiring of the GD-K7D2. The
three mounting holes on the back of the bracket are used to mount it to a vertical surface.
The installation bracket includes the socket, external wiring terminal strip, cable bushing,
and sample fittings.
Figure 4: Installation Bracket Component Location
Socket for
Main Board
External Wiring
Terminal Strip
Mounting Holes
Cable Bushing
Gas In
Sample Fitting
Gas Out
SampleFitting
Factory Installed
Jumper*
*Jumper is factory installed when
GD-K7D2 is used with a controller
that does not have a built in flow
alarm circuit and flow alarm
wiring terminals.

6 • Model GD-K7D2 (24 VDC) Sample Draw Transmitter
Socket
A card edge connector socket on the back of the bracket mates with the main circuit board
on the detection unit.
External Wiring Terminal Strip
A seven point terminal strip is located below the socket and used for wiring the GD-K7D2
to a controller.
A jumper is normally factory installed between the second and third terminals from the
right. This jumper is installed when the GD-K7D2 is used with a controller that does not
have a flow alarm circuit and flow alarm terminals for wiring to the GD-K7D2. It is not
installed when the GD-K7D2 is used with a controller that has flow alarm circuitry and
flow alarm terminals. See Wiring the GD-K7D2 to a Controller in the Installation section
for both types of wiring.
Cable Bushing
The 1/2 in. (1.25 cm) cable bushing on the bottom of the bracket allows you to route
wiring from a controller to the seven point external wiring terminal strip on the back of
the bracket.
Gas In & Gas Out Sample Fittings
There are two tube fittings on the bottom of the bracket, the gas in and gas out sample
fittings. The gas in fitting is forward of the gas out fitting. The gas in fitting allows sample
to enter the GD-K7D2 and the gas out fitting is for exhausting the sample. Both fittings
accept 6 mm O.D. x 4 mm I.D. Teflon PTFE tubing.