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9-2. Sensor Unit Installation/Replacement
1. Set the main unit power switch to the OFF position.
2. Pull forward the latches on both sides of the base unit and lift the main unit to remove it from
the base unit.
Sensor unit replacement should be performed every 6 months.
Replace the expired
sensor unit with a new one (except for combustible gas sensors (CHS-7)).
The expiration year/month is written on each sensor unit
’s individual package. Replace
the old one with a new one before the expiration date.
Turn off the gas detector prior to sensor unit replacement. Setting the main unit power
switch to the OFF position will turn off the trouble alarm output (open collector). If the
trouble alarm output is used to operate the interlocks of the external devices, release
the interlocks beforehand, as needed, to prevent a possible activation of the interlocks
during replacement.
Check that the target gas type and full scale value are correct before using a new sensor
unit. Also, check that the sensor unit expiration date has not been reached.
Note: The expiration year/month is not indicated on combustible gas sensor (CHS-7). CHS-7
is divided into two types, hot-wire combustible (CH) and catalytic (CS). The sensor life of CH
and CS types are 5 and 3 years from the installation date respectively.
To OFF position
Lift the cover flap open.
Main unit power switch
(2) Lift up the main unit.
(1) Pull forward the latches on both sides.
