CLEANING & MAINTENANCE
Fig 3. GASMAX II + GDS-IR
Apply power to the GASMAX II + GDS-IR and allow the
instrument to stabilize for at least one (1) hour.
IMPORTANT
- Be sure there are no hydrocarbon gases
present during the IR Zero procedure. If necessary, apply
a flow of nitrogen or known ‘zero air’ to the Cal Gas Inlet
(See Fig 3.).
Step 1: Setting IR Zero on the GDS-IR
Open the GASMAX II enclosure cover and loosen the two
thumbscrews that hold the display board in place. While
holding the display in one hand, PRESS and HOLD the
IR Zero
switch for 12 to 15 seconds, but not more than
20 seconds. If the GASMAX II Marker option is turned on,
the GASMAX II display will momentarily show the
message “IR ZERO” when the GDS-IR output drops to
2.2mA to indicate a successful zero setting. Replace the
display assembly and tighten the thumbscrews.
Step 2: Calibrating the GASMAX to the GDS-IR
Hold a magnetic wand over the DN / CAL button on the
lower left side of the GASMAX II display. When the CAL?
Message appears, confirm by holding the wand over the
EDIT key. Follow the instructions that appear on the
GASMAX II display to fully calibrate the GASMAX +
GDS-IR by applying zero and span gas to the sensor.
INITIAL STARTUP & CALIBRATION
Periodically open and inspect the of the hydrophobic filter
by removing the Outer Barrel Assembly.
The hydrophobic filter is a Teflon-coated stainless steel
mesh that keeps moisture and particulates out of the
optical path. A setscrew holds the filter to the GDS-IR
housing. Compressed air can be used to clean the filter
of dust and moisture.
To inspect or clean the optical path, remove the
hydrophobic filter by unscrewing the setscrew at the
bottom of the filter assembly. The filter will then slide off,
revealing the optical waveguide assembly.
The waveguide and waveguide collar can be removed by
inserting rigid instruments (Allen wrenches) into the holes
of the waveguide and collar. Turning the waveguide and
collar in opposite directions will loosen the waveguide
allowing the collar to be screwed down onto the
waveguide until both can be removed from the GDS-IR
housing. Clean the two sapphire windows with a lint-free
cloth and reassemble the unit.
Always perform an IR zero procedure as described above
if the unit is physically moved or disassembled.
S2
Ribbon to
1
2
4
3
P
W
R
O
U
T
4
-2
0
“E
C
H
E
M
”
O
U
T
4
-2
0
“L
E
L”
G
N
D
R
E
F
C
O
M
CATBEA
S
C7
C8
C1
C2
I/O Power
Supply
TB1
TB2
IR
Zero
Switch
Cal
Gas
Inlet
GDS-IR
Infrared Gas
Sensor
Outer
Barrel
Assembly
GASMAX II
Gas Monitor
