Biosystems EX CHEK Reference Manual - page 16
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battery are designed to provide up to 6
hours of continuous use. The NiMH battery
is sealed in the Ex Chek and should not be
disassembled in the field.
2.3.1 Low battery voltage alarms
When it is time to recharge the batteries a
"B" will appear in the lower left hand corner
of the display screen, and the audible alarm
will “beep” once per minute until the
batteries are replaced. Once the “B” is
displayed, the user should have
approximately 10 minutes of useful battery
life remaining.
2.3.2 Battery charging procedure
The Ex Chek must be
located in a non-hazardous location
during the charging cycle. Charging the
Ex Chek in a hazardous location may
impair intrinsic safety.
(1) Check that the instrument is turned off.
(If it is not, press the mode button until
the message "Release button".)
(2) Connect the charger cradle to the 110
VAC “wall cube” power source.
(3) Plug the “wall cube” in and check to see
that the “PWR” (power-on) indicator LED
on the charger cradle is lit.
(4) Slip the Ex Chek into the charger cradle
and check to see that the “FAST” (fast
charger) indicator LED on the charger
cradle is lit.
Note: The “FAST” indicator will
initially light up and remain lit for the
first 15 minutes no matter what the
battery pack voltage.
(5) When charging is complete the “FAST”
indicator will turn off. Charging is
complete any time after the “TRIC”
(trickle charge) indicator is lit.
Accuracy of the Ex Chek detector must
be verified by exposure to known
concentration test gas before the
instrument is put back into service.
CAUTION To achieve optimal charge and
ensure long battery life of the NIMH
battery, make sure that charging takes
place in an area where the ambient air
temperature is between 40 and 86
degrees Fahrenheit (5 and 30 degrees
Celsius). Charging the battery in
temperatures above or below this range
can damage the battery and will
drastically affect battery life.
2.4
Methods of sampling
The Ex Chek may be used in either diffusion
or sample-draw mode. In either mode, the
gas sample must enter the sensor
compartment for the instrument to register a
gas reading.
In diffusion mode, the atmosphere reaches
the sensor by diffusing through the sensor
port on the front of the instrument. Normal
air movements are enough to carry the
sample to the sensor. The sensor reacts
quickly to changes in the concentration of
the gas being measured.
It is also possible to use the Ex Chek to
sample remote locations with the hand-
aspirated sample-draw kit that is available
separately. During remote sampling, the
gas sample is drawn into the sensor
compartment through the probe assembly
and a length of tubing.
2.4.1 Using the hand aspirated
sample draw kit
(1) Connect the slip-on sample draw cup
with the squeeze bulb and hose
assembly. (Connect the end of the short
length of hose closest to the bulb to the
sample draw cup. Connect the other end
of the hose to the sample probe.)
(2) Cover the end of the sample draw probe
assembly with a finger, and squeeze the
aspirator bulb. If there are no leaks in
the sample draw kit components, the
bulb should stay deflated for a few
seconds.