Bacharach Portable Combustion Analyzer 24-9351 - Manual (Page 56)

PCA
Instruction 24-9351
5.8 Calibrate NX
(For PCA Models 30, 35, 60 & 65)
The Nitric Oxide sensor needs to be spanned at regular intervals to
determine that it still meets its accuracy specification. Because of the
toxicity of Nitric Oxide gas, however, unless your facility has the neces-
sary gas cylinders and personnel trained in the handling of toxic gases,
we recommend that the Nitric Oxide sensor be spanned by an authorized
Bacharach Service Center.
Material Required:
• Calibration Gas Fixture (Section 5.2)
• Gas Cylinder, 50 to 150 ppm Nitric Oxide with an analytical accuracy of
±1% (customer supplied)
Procedure:
1. Enter the Calibrate Menu Screen per Section 5.3. Then choose to
calibrate the NX sensor.
2. At the conclusion of Step 1 the pump should start running.
3. Using the Gas Fixture shown in Figure 5-1, attach the Nitric Oxide
calibration-gas cylinder to the analyzer’s GAS inlet.
4. Adjust the regulator of the calibration fixture for a flowmeter indica-
tion of approximately 2 SCFH.
5. Wait until the MEASURED reading on the screen stabilizes (approxi-
mately 3 minutes). Then use the
st
and keys to enter an
APPLIED value* that equals the concentration that is stamped on the
NX calibration-gas cylinder.
Typical Calibrate NX Screen During Calibration,
Using 100 ppm Nitric Oxide Calibration Gas:
CALIBRATE NX
MEASURED 092 PPM
APPLIED 0100 PPM
6. Press the key to calibrate the analyzer’s MEASURED value to
that of the APPLIED value. At this time the Calibrate Menu Screen is
redisplayed.
* The calibration range for this screen is 50 – 150 ppm. Any attempt to
calibrate outside range will cause the analyzer to display an error
message.
Calibration
5-8