Yokogawa Single Channel Oxygen Analyzer System ZR22/ZR402 - Manual (Page 20)

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IM 11M12A01-01E-A
Problem 2: Oxygen reading is abnormally low during normal operation.
Possible cause(s): The transport tube may be clogged and the eductor is drawing a vacuum.
NOTE: Cell damage may occur from excessive vacuum pressures.
Solution:
1. Verify that air flow to the eductor is adequate to draw a sample. (Max. 20 psi)
2. Remove power from the analyzer and adapter tee.
3. Turn off air supply to the eductor.
4. Remove the probe from the adapter.
5. Visually inspect the cell assembly area of the ZR22G probe for dust/particulate clogging the cell
screen.
6. Remove the blind flange and gasket.
7. Ensure that the transport tube is not clogged. If no clog exists, turn on air supply to the eductor to
verify a sample is being drawn.
8. Place all components, ensuring replacement of the gasket.
9. Confirm reference air flow rate to the ZR22G probe is 0.8 LPM.
10. Return to normal operation
NOTE: If the problem persists, unburned hydrocarbons may be present. Additional cleaning and
disassembly of the ZR22G probe may be required.
Problem 3: Oxygen reading is abnormally high
Possible causes(s):
• Possible leaks within the system.
• Eductor may be clogged
• Blowback solenoid in “constant on” position.
Solutions:
1. Ensure the gaskets are properly installed.
2. Ensure that the probe calibration gas fittings are air tight. If the calibration gas port is not being
used, it must be tightly sealed, as to not allow air into the probe.
3. Remove eductor and check for clogging. If the eductor is found to be clogged, clean or replace
the eductor.
4. Ensure that the blowback solenoid programming is correct in the ZR402G, G2 menu.
Problem 4: Blowback solenoid remains ON
Solution:
1. Confirm proper programming at the ZR402G (or AV550G) for contact output #3 (G2 menu).
Problem 5: Air eductor is clogged
Solution:
1. Clean or replace the eductor (M1132KA).
NOTE: If a constant high amount of dust or particulate is present, a Teflon eductor is available; Part
Number M1234WR-A.
Problem 6: Block valve does not close
Possible causes(s):
1. Confirm that at least at least 60 psi of air (80psi recommended) is attached to the solenoid for the
actuator.
2. Verify proper wiring