MAHLE RTI NTF-15H - Manual (Page 6)

Page 4
Pressure Effects
Readings from the Nitrogen Tester are proportional to the partial pressure of oxygen. The
partial pressure is equal to the concentration times the absolute pressure. Thus, the readings
are proportional to the concentration if the pressure is held constant. Therefore, the following
are recommended:
! Calibrate the Nitrogen Tester at the same pressure as the sample gas.
! If sample gases flow through tubing, use the same apparatus and flow rates when
calibrating as when measuring.
! The Nitrogen Tester oxygen sensor has been tested at pressures up to two
atmospheres absolute. Calibration or operation above this pressure is beyond the
intended use.
Humidity Effects
Humidity (non-condensing) has no effect on the performance of the Nitrogen Tester
other than diluting the gas, as long as there is no condensation. Depending on the
humidity, the gas may be diluted by as much as 4 percent, which proportionally
reduces the oxygen concentration. The device responds to the actual oxygen
concentration rather than the dry concentration. Environments where condensation
may occur are to be avoided since moisture may obstruct passage of gas to the
sensing surface, resulting in erroneous readings and slower response time.
For this reason, the following is recommended:
! Avoid usage in environments greater than 95 percent relative humidity.
CALIBRATION ERRORS AND ERROR CODES
The Nitrogen Tester has a self test feature built into the software to detect faulty calibrations,
oxygen sensor failures and low operating voltage. These are listed below, and include possible
actions to take, if an error code occurs.
E03: No valid calibration data available
Make sure unit has reached thermal equilibrium. Press and hold the Calibration Button for
three seconds to manually force a new calibration.
E04: Battery below minimum operating voltage
Unit has reached end of life.
CAL Err St: O2 Sensor reading not stable
Wait for displayed nitrogen reading to stabilize, when calibrating the device at 100 percent
oxygen.
Wait for unit to reach thermal equilibrium (Please note that this can take up to one half hour,
if the device is stored in temperatures outside the specified operating temperature range).