YOKOGAWA ZR202S, User Manual, Page: 132 / 163

<11. Inspection and Maintenance>
11-3
IM 11M13A01-04E
CAUTION
• If the sensor assembly is to be replaced, allow enough time for the detector to cool down from its
high temperature. Otherwise, you may get burned.
• If the cell assembly is to be replaced, be sure to replace the metal O-ring and the contact
together. Additionally, even in a case where the cell is not replaced, if the contact becomes
deformed and cannot make complete contact with the cell, replace the contact.
• If there is any corroded or discolored area in the metal O-ring groove in which the contact is
embedded, sand the groove with sandpaper or use a metal brush, and then sand further with a
higher grade of sandpaper (No. 1500 or so), or use an appropriate metal brush to eliminate any
sharp protrusions on the groove. The contact’s resistance should be minimized.
• Use cell assemblies manufactured in or after Sept. 2000: the serial number on the side of the cell
assembly should be 0J000 or later (for example: 0K123, 1AA01 etc.)
F11-2E.ai
Flame arrestor
assembly
Bolts (four)
Washers
(four)
Sensor (Cell)
U-shaped pipe
Filter
Metal O-ring
Contact
Probe
1/8 turn – tighten bolts 1/8 turn
(approximately 45°) each
U-shaped pipe
support
Figure 11.2 Exploded View of Sensor Assembly
CAUTION
Optional Inconel bolts have a high coefficient of expansion. If excess torque is applied while the bolts
are being tightened, abnormal strain or bolt breakage may result. So, tighten the bolts following the
instructions given above.