(b)
Make sure the calibration on the combustible scales are specific to hexane gas.
(c)
Make sure the alarm values are set to these limits:
1) 160 PPM
2) 10% of the LEL
3) 19.5% oxygen by volume.
(d)
Do these steps to make sure the combustible gas indicator operates correctly: 1) Make sure the indicator, sampling line, and sampling probe
(with dust filter) are clean and not damaged. 2) Put the indicator switch to the ON position. 3) Make sure there is enough charge on the battery for the
scheduled time in the fuel tank.
EFFECTIVITYùùùùùùùùùùùùùùùùùùùùùùùùùùùùùù. ú
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MAINTENANCE MANUAL
4) Let the indicator warm-up for 20 minutes before you look at the readings.
5) Adjust the indicator to zero in clean air for these scales: a) Oxygen b) PPM c) LEL
6) If there is a negative value during the use of the indicator, adjust the indicator scale(s) to zero in clean air.
NOTE: Do not turn the indicator off before you adjust the
____
scales.
(e)
Do these steps to do a check of the alarms: 1) To do a check of the oxygen alarm, blow across the probe until the alarm comes on (19.5%).
2) To do a check of the PPM and LEL scales, hold the tip of the probe over a solvent bottle or some solvent on a rag until the alarm comes on.
(f)
Put the combustible gas indicator on a stand or ladder next to the access door where you will enter the fuel tank. 1) To prevent the accidental movement of the combustible gas
indicator, safely attach the indicator to the stand or ladder.
G. Fuel Tank Purging
S 912-292
WARNING:_______OBEY THE PURGING AND FUEL TANK ENTRY PRECAUTIONS. FAILURE TO OBEY THE PURGING AND FUEL TANK ENTRY PRECAUTIONS CAN CAUSE SERIOUS INJURY OR DEATH TO PERSONS AND CAN CAUSE DAMAGE TO EQUIPMENT.
(1)
Read and obey the precautions in this task: Purging and Fuel Tank Entry Precautions.
S 492-293
(2)
VENTURI TYPE VENTILATION EQUIPMENT; Do these steps to install the air ventilation equipment (Fig. 203):
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