Yokogawa Integral Oxygen Analyzer ZR202 - Manual (Page 135)

<11.Inspection and Maintenance>
11-6
IM 11M12A01-04E
Replacement of heater assembly
Refer to Figure 11.4 as an aid in the following discussion.
Remove U-shaped pipe support
④, U-shaped pipe ⑤, Filter and the sensor (cell) ⑥, following
Section 11.1.2, earlier in this manual.
Remove the two screws
⑮ that tighten the cover ⑫ and slide it to the flange side. Remove the four
bolts ⑩ to remove the converter ⑯. Then remove the three connectors to which leadwire from the
heater and thermocouple is connected.
Loosen screw
⑲ until heater assembly  plate can be removed. There’s no need to remove O-ring ⑱
which prevents screw ⑲ from dropping out. Pull out connector ⑬. Loosen and remove the screw ⑧
with a special wrench (part no. K9470BX or equivalent) and then remove the heater assembly  from
the detector .
To reassemble the heater assembly, reverse the above procedure:
Insert the heater assembly
 into the detector , while inserting the calibration pipe in the detector
 into the heater section in the heater assembly  as well as in the bracket hole. Coat the screw ⑧
with grease (Never-Seez: G7067ZA) and tighten the screw ⑧ with a special tool (part no. K9470BX or
equivalent) with a tightening torque of 12N·m ± 10%.
Next, to install the O-rings
㉒ on the calibration-gas and reference-gas pipes, disassemble the
connector ⑬ in the following procedure:
First, remove the screw  and then remove the plate ⑰ and two caps ⑳. If the O-ring ㉒ remains
in the hole, pull them out from the back. Pass the heater and thermocouple leadwire through the
connector ⑬. Also, pass the calibration gas and reference gas pipes through the opening of the
connector ⑬. If the O-ring ㉒ fails, replace it with a new one.
Push the two caps ⑳ into the associated opening of the connector ⑬. Insert the plate ⑰, aligning it
with the groove of the cap ⑳, and tighten it with the screw . If you attempt to insert the calibration
gas and reference gas pipes into the connector ⑬ without disassembling the connector ⑬, the O-ring
may be damaged. Tighten screw ⑲ in the heater assembly  until connector ⑬ can’t move.
Reassemble in reverse order to the above disassembly procedure.
When installing the cell assembly
⑥, replace the metal O-ring ⑦ with a new one.
11.1.4 Replacement of Dust Filter
Set the dust filter ① in place using a special pin spanner (with a pin 4.5 mm in diameter: part no.
K9471UX or equivalent). If a dust filter that has already been replaced once is used again, apply
grease (Never-Seez: G7067ZA) to the threads of the dust filter.
11.1.5 Replacement of O-ring
The detector uses three different types of O-rings ⑭, , and ㉒. One O-ring alone ⑭, or two O-rings
 and ㉒ are used. (For a pressure compensating model, two O-rings are used for individual uses.
Two O-rings  and ㉒ are used for reference gas sealing and require periodic replacement.
11.1.6 Stopping and Re-starting Operation
<Stopping Operation>
When operation is stopped, take care of the followings so that the sensor of the detector cannot
become unused.