RKI Instruments Digester Gas Monitor - Manual (Page 39)

Digester Gas Monitor Operator’s Manual Starting Up the Digester Gas Monitor • 33
8. Any unused channels are configured as NOT USED in the Configuration Menu at the
factory. For any unused channels, NOT USED is displayed on the line for that
channel. If any channels have been configured as STANDBY in the Configuration
Menu, STANDBY is displayed on the line for that channel. See “Viewing and
Changing Channel Parameters” on page 51 for a description of the NOT USED and
STANDBY configurations.
9. Verify that the PILOT light is on. If the PILOT light is not on, see the troubleshooting
guide in “Troubleshooting” on page 79.
10. When the warm-up period is complete, the Digester Gas Monitor enters a 60 second
standby period. The display will alternate between the fresh air reading and the time
left before the first detection cycle begins. During this initial standby period, you can
perform a calibration if needed. See “Performing a Calibration” on page 63 for
instructions. In addition, you may enter any of the Digester Gas Monitor’s setup
menus during this time.
NOTE: If you enter Calibration Mode or one of the setup menus during the initial 60
second standby period, the 60 second count is paused and resumes once you
exit Calibration Mode or the setup menu.
11. Once the initial 60 second standby period has passed, the Digester Gas Monitor
begins a detection cycle with a pre-sample purge. For more description of the
sampling cycle, see “Detection Cycle” on page 35. During this first cycle, the flow
rates must be set during the sampling period as described in the next section and in
“Detection Cycle” on page 35. If you are unable to set the flow rates during the inital
cycle, a manual cycle must be initiated.
Adjusting the Flow Rates
The flow rates during a detection cycle are factory set but may require adjustment after the
installation of the fresh air inlet, calibration gas inlet, blow back exhaust, digester sample,
and aspirator/sample exhaust lines. In addition, because of differences between the
sample inlet restriction and the calibration inlet restriction, the flow rates may need
adjustment during a calibration. Follow this procedure if you notice that your flow rates are
not correct. Before adjusting flow rates, be sure that all inlet and/or exhaust lines are
connected to the appropriate fitting on the bottom of the housing.
If the flow rates need adjustment, they must be set during the sample period of a detection
cycle or during a calibration procedure. If the flow rates need adjustment during
calibration, the flow rates must be set again during the next sample period.
The Flow to Sensors flowmeter should always read 3.0 SCFH. The flow rate value for the
H
2
S Dilution Sample and H
2
S Dilution Air flowmeters depend on the detection range of
the H
2
S channel. The table below outlines the flowrate that each flowmeter should read for
the available H
2
S detection ranges.
Standby Mode
# of Samples 0
Next Detection Cycle
in 0D: 0H: 0M: 59S 1: METHANE 0 %VOL
2: OXYGEN 20.9 %VOL
3: CO2 0.0 %VOL
4: H2S 0 ppm