Teledyne TED 200-T Instruction Manual page 23

Symptom
A new sensor will not calibrate
in air. The TED 200-T display
flashes REPLACE SENSOR
or SEE TROUBLESHOOT
after a second attempt to
calibrate.
The unit successfully cali-
brates at 21%, but will not
calibrate at 100%. The dis-
play is flashing REPLACE
SENSOR or SEE TROUBLE-
SHOOT.
The TED 200-T does not react
to changes in oxygen concen-
tration, or the readings are
unstable and drifting.
Maintenance and Troubleshooting 3
Why
A new sensor must be
allowed to stabilize prior to
calibration.
A) The sensor must be allowed
to stabilize in 100% oxygen
before calibration is at-
tempted, or the oxygen con-
centration at the sensor is
less than 100%.
B) A stable low reading had
not been achieved during air
calibration.
Teledyne Analytical Instruments
What to Do
A) Wait 1–2 minutes and try
again.
B) Oxygen concentration at the
sensor is significantly higher
than 21%. Take the instru-
ment to a well-ventilated
area and repeat the calibra-
tion.
C) Try calibrating a known
good sensor; if this fails,
see symptom "Reading
drifts over 2–3%..."
A) Wait 1–2 minutes or until
the oxygen concentration
reading is stable; push the
CAL key twice; wait for cali-
bration sequence to finish.
B) Make sure that at least 12"
(30 cm.) of tubing is at-
tached to the exhaust side
of the tee adapter to pre-
vent backfilling. O
2
should not exceed 5 l/min.
C) Prevent dilution of gas with
H O vapor by removing hu-
2
midifiers, nebulizers, etc.
Check for leaks or open cir-
cuits.
D) Repeat air calibration; be
sure to allow enough time
for all O to diffuse; remove
2
plastic flow diverter.
E) Repeat 100% calibration.
F) Replace sensor.
A) Remove T-7 sensor from
tee adapter and unscrew
the plastic flow diverter. Us-
ing absorbent tissue or cot-
ton swab, gently wipe off
sensing surface inside
threaded portion of sensor
assembly.
B) Relocate unit away from
sources of RFI.
flow rate
3-3