Yokogawa Integral Oxygen Analyzer ZR202 - Manual (Page 149)

IM 11M13A01-04E 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 11 , following Section 11.1.2, earlier in this manual.
Remove the four bolts 10 to remove the converter 16 . Then remove the three
connectors to which lead wire from the heater and thermocouple is connected.
Loosen screw 19 until it can be removed from hole in heater strut assembly 23 plate.
O-ring 18 prevents screw 19 from dropping out. The O-ring does not loosen and
remove the screw 8 with a special wrench (part no. K9470BX or equivalent) 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
Ϯ 10%.
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
thermocouple lead wire 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 to secure connector 13 .
When installing the cell assembly 6 , replace the metal O-ring 7 with a new one.
11.1.4 Replacement of flame arrester assembly
If it takes longer for the analyzer to return to read the concentration of a sample gas
after calibration, the flame arrester may have become clogged. Inspect the flame arrester
and if necessary, clean or replace it.
Set the flame arrester assembly 1 in place using a special pin spanner (with a pin 4.5
mm in diameter: part no. K9471UX or equivalent). If a flame arrester assembly that has
already been replaced once is used again, apply grease (NEVER SEAZE: G7067ZA) to
the threads of the flame arrester assembly.
If the flame arrester assembly is clogged with dust, replace it with new one or wash it.
In case of the ATEX flameproof model (MS Code: ZR202S-A-...) or IECEx flameproof
model (MS Code: ZR202S-D-...), the flame arrester assembly
1 is bonded to the
detector 24 with an ceramic adhesive. To remove the flame arrester assembly 1 , crack
the hardened adhesive on the joint by tapping it with a flat head screwdriver and a
hammer or appropriate tools. After reattaching the flame arrester assembly
1 , apply a
small amount of ceramic adhesive (P/N G7018ZA), with a diameter not exceeding 10
mm, to the joint part. Be careful not to allow the ceramic adhesive to enter between the
female and the male screws. Before applying, stir the ceramic adhesive thoroughly. The
ceramic adhesive should be stored in a cool, dark place and has a shelf life of 6 months
from the date of shipment.