Document No. 715-7000
Revision E
Page 56 of 63
SYMPTOM
CAUSE
ACTION
NO screen
displays “1600”
and/or NO
2
screen
displays “21”
1. Bias voltage to the
sensors has been lost.
1. Recharge or replace battery and
allow 24 - 48 hours for the sensors
to re-bias.
NO
2
screen
displays 21 and
will not change
1. NO
2
sensor has been
exposed to NO
2
values in
excess of 21 ppm.
1. Allow room air or oxygen to be
aspirated into the AeroNOx
sampling block until NO
2
value
returns to zero. Calibrate the NO
2
channel. Exposure to high levels of
NO
2
will decrease the sensor’s life.
Either or both
screens display a
(-) hash mark
1. Sensors have drifted
below zero.
1. Zero sensors as outlined in the
calibration procedure (
SECTION V
).
NO / NO
2
values
drop suddenly
after water has
entered the
AeroNOx
sampling block
1. Water is preventing the
sampling gas from
reaching the sensor
membrane.
1. Run room air or oxygen through the
AeroNOx
to dry out the sampling
chamber. Calibrate the analyzer as
in
SECTION V
prior to putting the
AeroNOx
back into clinical use.
Use sample line P/N 415-0004 to
prevent water from entering the
AeroNOx
.
NO sensor will not
return to zero
1. Sensor has been exposed
to high levels of NO (>100
ppm).
1. Run room air or oxygen through the
analysis port until the value returns
to zero. The length of time this will
take will depend on how much NO
the sensor was exposed to and for
how long. Exposing the sensors to
high levels of NO will decrease the
sensor’s life.