Bacharach 300 - Thermocouple Span Calibration - R19; Low-Range Thermocouple Calibration

MODEL 300 COMBUSTION ANALYZER
Instruction 24-9223 4-9
4.3.2 Optional NO
X
& SO
2
Span Calibration
The optional NO
X
and SO
2
sensors are calibrated and installed at the
factory. Should you have reason to suspect the accuracy of either sensor,
BACHARACH recommends that the unit be sent to a qualified Service
Center (see the inside back cover) for calibration. If you have the qualified
facilities and personnel to make the calibration, span the sensors using a
procedure similar to the CO Span Calibration procedure described in
Section 4.3.1 substituting the appropriat gas (typically 100 ppm NO or
100 ppm SO
2
). Fig. 4-6 shows NO
X
and SO
2
span potentiometer locations.
WARNING!
Due to the highly toxic nature of the gases required to calibrate
the NO
X
and/or SO
2
sensor(s), only attempt to replace or cali-
brate these sensors if you are trained in the use and handling of
toxic gases; otherwise, these sensor(s) should be replaced and
calibrated by an authorized Bacharach Service Center.
4.4 THERMOCOUPLE SPAN CALIBRATION - R19
Two thermocouple calibration procedures are provided. The first proce-
dure under Section 4.4.1, which uses boiling water as the calibration-
temperature source, is relatively easy to perform, and provides thermo-
couple accuracy up to 1400°F (760°C). The second procedure under
Section 4.4.2, which uses a mV source to simulate a calibration tempera-
ture of 1700°F (927°C), is more complicated to perform, but ensures
thermocouple accuracy up to 2000°F (1093°C).
4.4.1 Low-Range Thermocouple Calibration
Up to 1400°F (760°C)
This procedure calibrates the probe’s thermocouple to be accurate up to a
temperature of 1400°F (760°C). Note that a thermocouple calibrated
using this procedure can be used at higher temperatures, but its accuracy
may be slightly compromised.
NOTE: The Ambient Temperature Calibration pot, R24, must be
adjusted to its correct setting before Thermocouple Span pot R19
can be adjusted.