Emerson Process Management IB106-340 instruction manual Pressure Regulator Optional Maintenance

Oxymitter 4000

Instruction Manual

IB-106-340 Rev. 2.4 April, 2001

f.Pressure Regulator (Optional) Maintenance

1.Pressure Adjustments. Reference air pressure regulator (8, Figure 6-13)is factory set to 20 psi (138 kPa). Adjust using the knob on top of the pressure regulator if necessary.

Do not use fingers to release valve stem. The valve may release air at high pressures and cause injury.

2.Condensation Drain. To drain excess moisture from the filter bowl of refer- ence air pressure regulator (8), use a screwdriver or comparable tool to peri- odically release valve stem on the bot- tom of the regulator.

g.Flowmeter Adjustments

1.Calibration Gas Flowmeter. Calibration gas flowmeter (17, Figure 6-13)regu- lates the calibration gas flow and must be set to 5 scfh. However, only adjust the flowmeter to 5 scfh after placing a new diffusion element on the end of the Oxymitter 4000. Adjusting the flowme- ter at any other time can pressurize the cell and bias the calibration.

In applications with a heavy dust load- ing, the O2 probe diffusion element may become plugged over time, caus- ing a slower speed of response. The best way to detect a plugged diffusion element is to note the time it takes the Oxymitter 4000 to return to the normal process reading after the last calibra- tion gas is removed and the calibration gas line is blocked off. A plugged ele- ment also can be indicated by a slightly lower reading on the flowmeter.

Change the diffusion element when the calibration gas flowmeter reads slightly lower during calibration or when the re- sponse time to the process flue gases becomes very slow. Each time the diffu- sion element is changed, reset the cali- bration gas flowmeter to 5 scfh and calibrate the Oxymitter 4000. For more information on changing the diffusion element, refer to paragraph 6-8.

2.Reference Air Flowmeter (Optional). Reference air flowmeter (16, Figure

6-13)regulates the reference air and must be set to 2 scfh. Adjust the flow with the knob on the bottom of the ref- erence air flowmeter when necessary.

h.Flowmeter Replacement

Use this procedure to replace either refer- ence air flowmeter (16, Figure 6-13)or cali- bration gas flowmeter (17).

1.Turn off power to the system.

2.Shut off the calibration gases at the cylinders.

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3.Loosen, but do not remove, four screws (13) securing flowmeter bracket

(25)to the manifold.

4.Flex the bottom of flowmeter bracket

(25)downward and away to disengage and remove from the manifold.

5.For reference air flowmeter (16), re- move pressure regulator (8) by discon- necting tubing (11) from elbow fitting

(10). Also, disconnect tubing (24) from straight fitting (23).

For calibration gas flowmeter (17), dis- connect tubing (18) at elbow fitting

(21). Also, disconnect gas tubing (2) from elbow fitting (15).

Rosemount Analytical Inc. A Division of Emerson Process Management Maintenance and Service 6-21