Advanced Instruments, Inc.
Gas Connections
The GPR-2500A with its standard flow through configuration is designed for positive pressure samples
and requires connections for incoming sample and outgoing vent lines. The user is responsible for
calibration gases and other required components, see below.
Flow rates of 1-5 SCFH cause no appreciable change in the oxygen reading. However, flow rates above 5
SCFH generate backpressure and erroneous oxygen readings because the diameter of the integral tubing
cannot evacuate the sample gas at the higher flow rate. A flow indicator with an integral metering valve
upstream of the sensor is recommended as a means of controlling the flow rate of the sample gas. A flow
rate of 1-2 SCFH or 0.4-1 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
vacuum on the sensor and may damage the sensor (voiding the sensor warranty).
Procedure of Connecting Sample Gas:
•
Designate one of the bulkhead tube fittings as the VENT and the other as SAMPLE.
•
Regulate the sample/span gas pressure to 5-30 PSIG.
•
Connect a 1/8” vent line to the compression fitting to be used for venting the sample.
•
Connect a 1/8” ZERO, SPAN or SAMPLE line to the fitting designated SAMPLE.
•
If equipped with optional fittings and/or sample system, connect the ZERO and or SPAN gas
lines.
•
Allow gas to flow through the transmitters and set the flow rate to 1-2 SCFH.
Installing the Oxygen Sensor
•
Loosen the two (2) anchors securing the top lid of the enclosure.
•
Remove the oxygen sensor from the bag.
•
Screw the oxygen sensor into the sensor flow-through housing, finger tighten plus one half (1/4)
turn to ensure a good seal from the o-ring affixed to the sensor.
•
Remove the shorting device (looped wire) from the receptacle located at the rear of the sensor.
•
Assure the keyway registration of the female plug on the cable and male receptacle on the
sensor match up.
Sample Vent
Sample In
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