ABB Endura AZ20 series Maintenance Manual

Also see for Endura AZ20 series: User guide Instruction Manual Instructions User guide

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ABB Endura AZ20 series Maintenance Manual Manual pdf 22 page image

Combustion Oxygen MonitorEndura AZ20 Series Probe 5 Dismantling and Reassembly – Probe20 IM/AZ20M–EN Rev. B5.8 Replacing the Thermocouple /Electrode AssemblyBefore replacing the thermocouple and electrode assembly:1. Ensure replacement thermocouple and electrodeassembly and C-ring kits are available – refer to Section7.7, page 44.2. Remove the probe from its mounting – refer to Section5.4, page 14 (integral probe) or Section 5.5, page 14(remote probe).3. Remove the probe end cap as detailed in Section 5.6.1,page 15.5.8.1 Removing the Thermocouple / Electrode AssemblyReferring to Fig. 5.7:1. At the probe head, disconnect the red (Cell +), green (TC+)and white (TC–) sleeved wires A from the inner terminalblock connections.2. Unscrew and remove M4 screw C.3. Check if the cell is welded to the electrode tip by gentlypulling the white and green sleeved wires D.4. If resistance is felt, check if cell is welded to the helicalcontact at the end of the thermocouple / electrodeassembly – refer to Section 5.7.2, page 16 (step 3). Whenthe cell has been released / removed, proceed to step 5.5. The thermocouple / electrode assembly is very fragile, sowithdraw the thermocouple / electrode assembly F fromthe probe body carefully, providing support G along thelength of the assembly and keeping it straight.6. Lay the thermocouple / electrode assembly on a longclean flat surface.7. Proceed to Section 5.8.2, page 22 to fit a newthermocouple / electrode assembly.Note. Check all items including the extension insulators fordamage as they are removed. Keep items for reuse in aclean safe place. Replace any damaged items with newreplacements. Never reuse damaged insulators. Caution. AutoCal versions only – if necessary,disconnect the test gas to sensor tube B to allowaccess to the terminal connectors.Caution. Do not pull the Cell + (red sleeve) wire Eto check for thermocouple / electrode assembly play.