EXTECH
INSTRUMENTS
4
CO40
‐
en
‐
GB_v1.3
12/14
Operation
Powering
the
meter
Momentarily
press
the
button
to
power
on
the
meter.
Hold
the
button
for
2
seconds
to
turn
off
the
meter.
During
measurement,
if
the
alarm
is
sounding
(audible
beeper)
press
the
button
momentarily
to
turn
off
the
beeper.
Press
again
to
activate
the
beeper.
The
alarm
beeper
is
set
to
ON
by
default.
The
meter
can
be
powered
by
4
AAA
batteries
or
AC
adaptor.
Auto
Power
Off
The
CO40
will
automatically
turn
off
after
15
minutes
of
inactivity.
To
disable
the
auto
power
off
function:
With
the
meter
OFF,
press
and
hold
the
HOLD
button
and
then
press
the
Power
button.
The
LCD
will
show
“
n
”,
and
will
then
return
to
normal
measurement
mode.
Measurements
When
the
meter
is
turned
on
a
self
‐
test
is
performed
as
the
LCD
counts
from
“9999”
down
to
“0000”
and
then
enters
the
normal
mode
of
operation
where
measurements
are
taken
by
the
sensors
and
displayed
on
the
LCD.
The
upper
LCD
area
shows
the
CO
reading
in
ppm
and
the
lower
LCD
area
shows
the
air
temperature
reading
in
o
C/
o
F
units
of
measure.
Selecting
o
C/
o
F
units
of
measure
Press
the
UNIT
button
to
select
the
desired
temperature
unit
of
measure.
Maximum
Reading
Memory
Momentarily
press
the
M
button
to
view
the
maximum
readings
captured
since
the
meter
was
powered
on
(the
MAX
icon
will
be
appear).
Press
M
button
again
to
return
to
normal
operation.
Data
Hold
Momentarily
press
the
HOLD
button
to
freeze
the
displayed
readings
(the
HOLD
icon
will
appear).
Press
the
HOLD
button
again
to
return
to
normal
operation.
Calibration
Press
and
hold
the
MODE
button
for
2
seconds
to
enter
the
self
‐
calibration
mode.
Ensure
that
there
is
no
CO
present
while
calibrating.
The
LCD
will
display
“
CAL
”
and
“
ooooo
”
flashing.
Wait
for
approximately
fifteen
seconds,
until
the
calibration
is
completed.
“
End
”
appears
on
the
screen
when
calibration
has
completed.
After
five
seconds,
the
meter
then
returns
to
its
normal
measurement
mode.
