YOKOGAWA ZO21DW, User Manual, Page: 30 / 39

<7. INSPECTION AND MAINTENANCE>
7-1
IM 11M03A02-00E
7. INSPECTION AND MAINTENANCE
This chapter describes the inspection and maintenance procedures for the ZO21DW Zirconia
Oxygen Analyzer to maintain its measuring performance and normal operating conditions.
CAUTION
When checking the detector, carefully observe the following:
(1) Do NOT touch the probe if it has been in operation immediately just before being checked.
(The sensor at the tip of the probe heats up to 750°C during operation. If you touch it, you
will get burned.)
(2) Do not subject the probe to shock or cool it rapidly.
The sensor is made of ceramic (zirconia). If the detector is dropped or bumped into
something, the sensor may be damaged and no longer work.
(3) Do not reuse a metal O-ring to seal the cell assembly. If you replace the cell or remove it
from the probe for checking, be sure to replace the metal O-ring. Otherwise, the furnace gas
may leak, and then the leaking corrosive gas will cause the built-in heater or thermocouple
to go open circuit, or the detector may corrode.
(4) Handle the probe with care so that the dust-filter mounted screws on the tip of the probe do
not hurt your finger(s).
(5) Before opening or closing the terminal box, first remove dust, sand, or the like from the
terminal box cover.