Analytical Industries GPR-1800 IS ATEX Trace PPM Oxygen Transmitter - Manual (Page 16)

Advanced Instruments, Inc
16
Gas Connections
The GPR-1800 IS with its standard flow through configuration is designed for positive pressure samples and
requires connections for incoming sample and outgoing vent lines. Zero and span inlet ports are offered as
part of the optional sample systems. The user is responsible for calibration gases and other required
components, see below.
Procedure:
Caution: Do not change the factory setting until instructed to do in this manual.
If analyzer has no marking for sample inlet and sample vent, designate one of the bulkhead tube fittings as
the VENT and the other as SAMPLE.
Regulate the sample pressure as described in “Pressure and Flow” section above.
Connect a 1/8” or a ¼” vent line to the compression fitting to be used for venting the sample.
Connect a 1/8” or ¼” sample line to the compression fitting to be used to bring SAMPLE gas to the analyzer.
If equipped with optional SPAN and/or ZERO ports, connect the SPAN and the ZERO gas lines to the
respective SPAN and ZERO ports of the analyzer
Set the SAMPLE, SPAN and the ZERO gas pressure between 5-30 psig..
Select sample gas and allow it to flow through the transmitters and set the flow rate to1- 2 SCFH.
Note: If equipped with the optional H2S sample conditioning system: Regulate the pressure so that it does
not exceed 30 psig.
Flow rates of 1-5 SCFH cause no appreciable change in the oxygen reading. However, flow rates above 5
SCFH may generate a backpressure and cause erroneous oxygen readings due to fact that the smaller
diameter of the integral sample system tubing cannot vent the sample gas quickly at higher flow rates. If the
analyzer is not equipped with an integral flow control valve, a flow control metering valve with a flow
indicator upstream of the sensor must be installed to control the flow rate of the sample gas. A flow rate of 1-
2 SCFH or 0.5-1 liter per minute is recommended for optimum performance.
Caution: Do not place your finger over the vent (it pressurizes the sensor) to test the flow
indicator when gas is flowing to the sensor. Removing your finger (the restriction) generates a
sudden vacuum on the sensor and may lead to electrolyte leakage thus causing damage to the
sensor (will void sensor warranty).