To Isolate The Measurement Cell For Short-Term Shutdown; To Isolate The Scs For Short-Term Shutdown - Endress+Hauser SpectraSensors 2-Pack Analyzer System Hardware Installation And Maintenance Manual

2-Pack Analyzer System
All valves, regulators, switches, etc. should be operated in
accordance with site lock-out/tag-out procedures.
To isolate the measurement cell for short‐term shutdown
The analyzer can be isolated from the primary sample bypass section for short-
term shutdown or maintenance of the analyzer while allowing the sample
bypass flow to continue in a steady-state mode.
Due to the high pressure of the process sample, it is advisable to
allow the sample bypass flow to continue during short-term
isolation of the analyzer. Continuing sample bypass flow allows
the field pressure regulator to continue normal operation without
possible overpressure and activation of the relief valve in the
event the pressure regulator leaks when the downstream flow is
discontinued.
1. Close the sample flow meter metering valve (adjustment knob
turned clockwise) for each measurement analyzer. Do not over-
tighten the metering valves or damage could occur.
2. Allow any residual gas to flow out of the measurement cells.
Never purge the analyzer with air or nitrogen while the system is
powered up.
3. Close the low pressure flare or atmospheric vent header shut-off
valve for the effluent from each measurement cell.
If the system will not be out of service for an extended period, it
is advised that power remain applied to the sample transport line
electric tracer, if applicable, and the sample system enclosure
heater.
To isolate the SCS for short‐term shutdown
The SCS can be isolated from the process sample tap for short-term shutdown
or maintenance of the SCS without requiring the shutdown of the field pressure
reducing station.
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4 8 4900002256 rev. B 4-13-21