Teledyne MD300 - Oxygen analyzer and monitor (Diving) - Manual (Page 32)

Service Manual AD300/MD300
Teledyne Analytical Instruments 32
Symptom Why What To Do
higher than 21%.
Take the instrument
to a well-ventilated
area and check the
reading again.
D) Try calibrating with a
known good sensor;
if this fails, see
symptom "Reading
drifts over 2
–3%..."
The display is flashing
√ SENSOR
The unit has detected a
fault in the signal from
the sensor.
Sensor has expired.
The sensor has been
exposed to a gas
containing little or no
oxygen.
A) Check sensor cable
connections and
make sure they are
completely inserted
into the mating
connector and the
capture nut is firmly
in place.
B) Expose the sensor
in 100% O2 and
check calibration.
C) The sensor output
has fallen to a level
where it is no longer
usable. Replace
sensor.
The oxygen reading
fluctuates or appears to
be incorrect. Like all O2 sensors, the
R17S detects the
changes in the partial
pressure of O2. A) During calibration,
make sure there is
no restrictions on
exhaust side of
sensor. If the reading
changes with flow,
the sensor is
pressurized or there
may be a leak in the
system.
B) If a high degree of
accuracy is desired,
or the concentration
of O2 is in excess of
40%, calibration with
100% is recom-
mended.