RKI Instruments HS-94 - Manual (Page 9)

SENSOR FAIL This alarm will sound if the sensor is missing or
has an internal open connection. This type of
alarm is indicated by the steady audible tone,
and with a large “X” appearing on the display
upper left. To resolve, verify that there is a sensor
in the instrument, or, replace the sensor if
necessary.
CALIBRATION AND MAINTENANCE
The 94 series microprocessor circuit allow the instrument to be calibrated and zeroed
completely with the external buttons. There are no internal user adjustments.
Note
Adjust the instrument Zero (or oxygen span at 20.9 %) if a gas reading drifts off zero
(or 20.9 %) or when a sensor has been replaced. All calibration and Zero adjustments
should be done in a known clean air environment.
Calibration Supplies and Equipment
To adjust the 94 series monitors, you will need the appropriate calibration gases and
supplies.These are readily available from RKI in an RKI Calibration Kit. The kits contain
calibration gas, valve, test cup, tubing, and any other accessories necessary. Although
other concentrations could be used, the recommended calibration gas concentrations
are as follows:
HS-94 25 ppm H2S in nitrogen or in air.
CO-94 50 ppm CO in nitrogen or in air.
OX-94 100 % nitrogen.
Entering Calibration Mode:
To access calibration mode on the 94 series instruments, the unit must be initially turned
on a special way. Turn the instrument OFF and turn back on as follows:
1. Press and hold the AIR button.
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