Yokogawa Multi Channel Oxygen Analyzer System ZR22/AV550G - Manual (Page 203)

IM 11M12D01-01E 11-9
11. Inspection and Maintenance
Replacement of heater strut assembly (ZR22G : Style S2 and after)
Refer to Figure 11.7 as an aid in the following discussion.
Remove the cell assembly (6), following Section 11.3.2, earlier in this manual. Open the
terminal box (16) and remove the three terminal connections – CELL +, TC + and TC -.
Before disconnect the HTR terminals, remove the terminal block screw (28). Keeping
the other terminal remaining to be connected. Disconnect the two HTR connections.
(These terminals have no polarity.)
Remove the two screws (15) that fasten the cover (12) and slide it to the flange side.
Remove the four bolts (10) and terminal box (16) with care so that the already discon-
nected wire will not get caught in the terminal box.
In case of the pressure compensation type detector, remove the screw (35) and the plate
(37) on the adapter (35). Remove the adapter (35), drawing out the wires of the heater
strut assy (23) from it.
Loosen Screw (19) until Heater Strut Assembly (23) plate can be removed.
There’s no need to remove O-ring (18) which prevents Screw (19) from coming out.
Pull out connector (13).
Loosen and remove the screw (8) with a special wrench (part no. K9470BX or equiva-
lent) and then remove the heater strut assembly (23) from the detector (24).
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 percent.
Next, to install the O-rings (22) on the calibration-gas and reference-gas pipes, disas-
semble the connector (13) in the following procedure:
First, 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. Pass the heater and thermo-
couple 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 (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. Tighten Screw
(19) in Heater Strut Assembly (23) until connector (13) 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.