Fresh Air/Zero Calibration; Functional (Bump) Testing (Toxic Sensor Versions) - Honeywell ToxiPro CO Reference Manual

3.3

Fresh air/zero calibration

To initiate the fresh air/zero calibration:
1. From the current gas reading screen, press the
MODE button three times within two seconds to
begin the fresh air/zero calibration sequence.
The ToxiPro will briefly display "CAL" and then
begin a 5-second countdown with the 0-CAL icon
lit.
→
2. Press the MODE button before the end of the 5-
second countdown to begin the fresh air/zero
calibration. The fresh air/zero calibration has
been successfully initiated when the ToxiPro
alternates between the following two screens:
3. For instruments equipped with a toxic gas sensor,
the fresh air/zero calibration is complete when the
instrument begins a second 5-second countdown
for the span calibration. If span calibration is not
required, allow the countdown to reach 0 without
pressing the MODE button. For further
instructions concerning the span calibration of
toxic sensor-equipped models, proceed to
section 3.5.
For ToxiPro O models, calibration is complete
2
when the instrument returns to the current gas
readings screen. If the fresh air/zero calibration
attempt fails, proceed to section 3.6.1.
Fresh air/zero calibrations
may only be performed in an atmosphere that is
known to contain 20.9% oxygen and 0 PPM toxic
gas. Performing the fresh air/zero calibration in an
atmosphere that is not comprised of 20.9% oxygen
and 0 PPM toxic gas may lead to inaccurate and
potentially dangerous readings.
3.4 Functional (bump) testing
(toxic sensor versions)
The accuracy of ToxiPro instruments may be verified at
any time by a simple functional (bump) test. To perform
a functional (bump) test, do the following:
1. Turn the ToxiPro on and wait at least three
minutes to allow the readings to fully stabilize. If
the sensor has just been replaced, it must be
allowed to stabilize prior to performing a
functional (bump) test. See section 4.2 for further
details.
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2. Make sure the instrument is located in fresh air.
3. Verify that the current gas readings match the
concentrations present in fresh air. The reading
for toxic gases should be 0 parts-per-million
(PPM) in fresh air. If the reading is anything other
than 0 PPM proceed to section 3.3 and perform a
fresh air/zero calibration before continuing.
4. Apply the calibration gas as shown in figure 3.4.
Figure 3.4: Proper bump-test/span calibration set-up
for toxic sensor-equipped instruments
Note: ToxiPro instruments equipped with a chlorine
dioxide (ClO ) sensor require a chlorine dioxide
2
generator as a calibration gas source.
5. Wait for the readings to stabilize. (Forty-five
seconds to one minute is usually sufficient.)
6. Note the readings. Readings are considered
accurate if they are between 90% and 120% of
the expected value. If the readings are
considered accurate, then the instrument may be
used without further adjustment. If readings are
considered inaccurate, the instrument must be
adjusted using the "span" calibration procedures
discussed in section 3.5 before further use.
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