Analytical Industries GPR-2500 A Oxygen Analyzer - Manual (Page 13)

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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 the
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 2 SCFH or 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:
1. Caution: Do not change the factory setting until instructed to do in this manual.
2. Designate one of the bulkhead tube fittings as the VENT and the other SAMPLE.
3. Regulate the pressure as described in Pressure and Flow above.
4. Connect a 1/8” vent line to the compression fitting to be used for venting the sample.
5. Connect a 1/8” ZERO, SPAN or SAMPLE line to the fitting designated SAMPLE.
6. If equipped with optional fittings and/or sample system, connect the ZERO and SPAN gas lines.
7. Allow gas to flow through the transmitters and set the flow rate to 2 SCFH.
Integral Oxygen Sensor:
1. Remove the four (4) screws securing the top section of the
enclosure, set them aside for reinstallation and raise the hinged
top section 180º until it locks in place.
2. Caution: Do not remove or discard the gaskets from either the
enclosure or junction box. Failure to reinstall either gasket will
void the NEMA 4 rating and RFI protection.
3. The transmitters design provides protection from RFI that is
maintained by leaving specific mating areas of the enclosure
unpainted to maintain conductivity the gasket, top and bottom
sections of the enclosure. These unpainted areas are protected
by gaskets and contribute to maintaining the NEMA 4 rating. Do
not paint these areas. Painting will negate the RFI protection.
4. Remove the oxygen sensor from the bag.
5. Screw the oxygen sensor into the sensor flow housing,
equipped with elbows and tubing, finger tighten plus one half
(1/2) turn to ensure a good seal from the o-ring affixed to the
sensor.
6. Remove the shorting device (looped wire) from the receptacle
located at the rear of the sensor. Minimize the time the sensor
is exposed to ambient air.