Yokogawa Single Channel Oxygen Analyzer System ZR22/ZR402 - Manual (Page 178)

IM 11M13A01-02E 11-7
11. Inspection and Maintenance
Replacement of heater strut assembly
Refer to Figure 11.4 as an aid in the following discussion.
Remove the cell assembly 6 , following Section 11.1.2, earlier in this manual. Open the
terminal box 14 and remove the three terminal connections – CELL +, TC + and TC -.
Before disconnect the HTR terminals, remove the terminal block screw 26 . Keeping the
other terminal remaining to be connected. Disconnect the two HTR connections. (These
terminals have no polarity.)
Remove the four bolts 10 and terminal box 14 with care so that the already discon-
nected wire will not get caught in the terminal box.
Loosen Screw 17 until Heater Strut Assembly 21 plate can be removed.
There’s no need to remove O-ring 16 which prevents Screw 17 from coming out.
Pull out connector 12 .
Loosen and remove the screw 8 with a special wrench (part no. K9470BX or equiva-
lent) and then remove the heater strut assembly 21 from the detector 22 .
To reassemble the heater strut assembly, reverse the above procedure:
Insert the heater strut assembly 21 into the detector 22 , while inserting the calibration
pipe in the detector 22 into the heater section in the heater strut assembly 21 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 percent.
Next, to install the O-rings 20 on the calibration-gas and reference-gas pipes, disas-
semble the connector 12 in the following procedure:
First, remove the screw 23 and then remove the plate 15 and two caps 18 . If the O-ring
20 remains in the hole, pull them out from the back. Pass the heater and thermocouple
leadwire through the connector 12 . Also, pass the calibration-gas and reference-gas
pipes through the opening of the connector 12 . If the O-ring 20 fails, replace it with a
new one.
Push the two caps 18 into the associated opening of the connector 13 . Insert the plate
(15), aligning it with the groove of the cap 18 , and tighten it with the screw 23 . If you
attempt to insert the calibration-gas and reference-gas pipes into the connector 12
without disassembling the connector 12 , the O-ring may be damaged. Tighten the
Tighten Screw 17 in Heater Strut Assembly 21 until connector 12 can’t move.
Reassemble in reverse order to the above disassembly procedure.
The two wires with ceramic insulators from the heater strut assembly are heater wires,
and the single-core shielded wire is the cell signal + terminal; for the two-core shielded
cable, the semi-translucent rubber-sheathed wire is the thermocouple + terminal, and the
other wire is the
Ϫterminal. (If the wires are marked, match the markings with those on
the terminal board).
When installing the cell assembly 6 , replace the metal O-ring 7 with a new one.