RKI Instruments GD-70D4A-XX - Manual (Page 5)

Model GD-70D4A-XX Sample Draw Transmitter • 2
Description
This section describes the components of the GD-70D4A-XX. It consists of the enclosure and a
GD-70D and a power supply mounted inside. The “XX” in the part number represents a number
that denotes the target gas and changes depending on the target gas. The “A” denotes that the unit
runs from AC power. For example, the part number for a detector head for ozone (O
3
) detection is
GD-70D4A-O3. Consult RKI Instruments, Inc. for a complete list of available part numbers.
A hydrophobic sample filter is also provided with the GD-70D4A-XX for installation at the inlet
fitting. The filter has a short length of gray flexible tubing on each end and can be connected to the
short tubing stub on the GD-70D4A-XX inlet fitting. The filter scrubs particulates out of the sample
stream and keeps water and many other liquids from entering the GD-70D4A-XX flow system.
Enclosure
The enclosure is a type NEMA 4X plastic enclosure designed for use in areas that are subject to
rain or hosing down. A mounting foot is installed in each corner. Two sample fittings are mounted
on the bottom right of the enclosure and two 3/4” conduit hubs are mounted to the left of the sample
fittings.
Sample Fittings
The inlet fitting is on the bottom right of the enclosure and the exhaust fitting is to the left of the
inlet fitting. The fittings accept 1/4”O.D. x 1/8” I.D. Teflon tubing. The inlet fitting has a short
factory installed tubing stub for use with the hydrophobic filter.
Conduit Hubs
Two 3/4” conduit hubs are located to the left of the sample fittings. They are used for routing wiring
into the enclosure by using conduit or an appropriate cable bushing.
Inlet Fitting Tubing Stub
A short tubing stub comes factory installed in the inlet fitting. It is used for connecting the
hydrophobic filter. If the hydrophobic filter is not used, the tubing stub needs to be removed and
replaced with tubing. Do not pull the tubing stub downward to remove it. Instead, unscrew the inlet
fitting, push the tubing stub up and out of the inlet fitting and push the new tubing up through the
inlet fitting. See Figure 2 for the inlet fitting layout.
GD-70D & Power Supply
The GD-70D sample draw detector head is mounted to a plate inside the enclosure. The GD-70D
sample fittings are factory connected to the sample fittings on the NEMA 4X enclosure. The GD-
70D is powered with 24 VDC supplied by a power supply that operates from a 100 - 240 VAC
input. The GD-70D is factory wired to the power supply. See the GD-70D operator’s manual for a
complete description of the GD-70D.