Teledyne MD300 - Oxygen analyzer and monitor (Diving) - Manual (Page 31)

Portable Oxygen Monitor Service Manual
Teledyne Analytical Instruments 31
unit, the discrepancy in oxygen readings persists, the problem is most
likely elsewhere. Further investigation should be made until the
discrepancy in readings is resolved. The troubleshooting section of this
manual may provide additional assistance in locating the problem.
Note: The MSDS on this material is available upon request
through the Teledyne Environmental, Health and Safety
Coordinator at (626) 934-1592 or can be viewed and
downloaded from our web site at www.teledyne-ai.com.
3.6 Troubleshooting
The AD300 and MD300 oxygen monitors provide a variety of built-in
safety features that prevent its use when a fault is detected. When a unit
displays the message √ SENSOR and sounds the audible and visual alarm
continuously, it is an indication of a faulty connection between the sensor and
the unit or an expired or faulty sensor. To determine where the difficulty lies,
refer to the following guidelines in Table 3-1.
Table 3-1 Troubleshooting
Symptom Why What To Do
New sensor responds
slow or drifts. If the sensor is new and
was just removed from
its sealed bag it may
need to run for several
hours. A) Wait 30 minutes and
recalibrate.
Sensor will not read below
22 % after calibration in
100% O2. Calibration in 100% was
invalid or the room air is
contaminated with
excess oxygen. A) Recalibrate using
dry gas making sure
the reading
stabilizes before
making any
adjustments.
B) Make sure that at
least 6" (30 cm.) of
tubing is attached to
the exhaust side of
the tee adapter to
prevent back filling.
O2 flow rate should
not exceed 5 l/min.
C) Oxygen
concentration at the
sensor is significantly