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Servicing
Pressure Regulator(s) Adjustment
7-52
Model 146i Instruction Manual
3. Connect a source of zero air to the zero air bulkhead connector and the
GAS A bulkhead fitting (located on the rear panel).
4. Activate the Service mode. Refer to
page
7-11, then return to the next step in this procedure.
5. From the Main Menu, press
, scroll to Instrument Configuration, press
all appropriate options.
6. Set all parameters that apply as follows:
GAS A
ZERO
PERM OFF
OZONE OFF
PHOT OFF
Note To acquire maximum flow setting, go to Service > Flow Control
Selection > Zero Scale, and use the zero flow controller zero scale value
listed as the appropriate input for GAS A.
7. If the instrument includes an output pressure regulator, reduce the
output pressure to zero on the gauge.
8. Set the back pressure regulator to indicate a flow of 150 sccm on the
digital flow meter.
9. Change the GAS A flow rate to 400 sccm and observe the digital flow
meter to verify that the flow rate remains greater than 125 sccm.
10. Disconnect the digital flow meter and all associated plumbing,
reconnect the instrument plumbing and tighten securely.
11. Set GAS A to OFF and set the output pressure regulator to 10 psig.
"Accessing the Service Mode"
to scroll to Diagnostics, press
Maximum flow (see Note)
0.000 PPM
0.000 PPM
0.0%
on
, and enable
Thermo Fisher Scientific
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Troubleshooting
