Yokogawa Integral Oxygen Analyzer ZR202 - Manual (Page 11)

<2. Instruction for Replacement of the Heater Unit>
2-2
IM 11M12A01-21E
CAUTION
If the heater strut assembly cannot be removed because a screw has fused to its thread, one of our
service representatives can fix it.
2.1.2 Replacement of the Heater Unit
1. Removing of the Sensor (Cell)
Remove the U-shaped pipe support, the U-shaped pipe, the Filter and the Sensor (Cell) according to
Sec. 2.1.1 “Removal procedures for Sensor Assembly”.
2. Removing of the Terminal Box
(1) Open the terminal box
⑯ and remove the three terminal connections (CELL+, TC+ and TC-).
(2) To disconnect the HTR terminals, remove the terminal block screw ㉘. The other terminal
connections remain connected; disconnect the two HTR connections. (These terminals have no
polarity.)
(3) Remove the two screws ⑮ that fasten the cover ⑫ and slide it to the flange side.
(4) Remove the four bolts ⑩ and the terminal box ⑯ with care so that the already disconnected wire
will not get caught in the terminal box.
3. Replacement of Heater Strut Assembly
(1) Loosen screw
⑲ until heater strut assembly’s plate ⑰ can be removed. There’s no need to
remove O-ring ⑱ which prevents screw ⑲ from coming out. Pull out connector ⑬.
(2) Loosen and remove the screw ⑧ with a special tool (part no. K9470BX or equivalent) and then
remove the heater strut assembly ㉓ from the detector ㉔.
(3) To reassemble the heater strut assembly, reverse the above procedure:
Insert the heater strut assembly ㉓ into the detector ㉔, while inserting the calibration pipe in
the detector ㉔ into the heater section in the heater strut assembly ㉓ 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%. (screw
⑧ attached with heater strut assembly ㉓ is shipped with coating.)
4. Assembling of Connector
(1) To install the O-rings
㉒ on the calibration gas and reference gas pipes, disassemble the
connector ⑬ in the following procedure.
Remove the screw ㉕ 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.
(2) Pass the heater and thermocouple lead-wire through the connector ⑬. Also, pass the calibration
gas and reference gas pipes through the holes of the connector ⑬ .
(3) Insert the calibration gas and reference gas pipes into O-rings ㉒ after confirming no damage to
O-rings. If the O-ring ㉒ fails, replace it with a new one.
(4) 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 ㉕. 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.
(5) Tighten the screw ⑲ in heater strut assembly ㉓ until connector ⑬ cannot move.