3
Span
Calibration
Warning:
You
must
be
in
a
well
‐
ventilated
area
before
starting
Span
Calibration.
Breathing
4%
CO2
gas
in
an
enclosed
area
can
result
in
dizziness,
shortness
of
breath,
or
unconsciousness.
Device
cannot
be
span
calibrated
above
3,000
ft.
(900m)
altitude.
1.
Attach
tubing
between
the
4%
CO2
gas
cylinder
and
the
calibration
port.
2.
Turn
on
the
gas
regulator.
Flow
rate
should
be
between
0.15
‐
0.3
liters
per
minute.
3.
Wait
until
the
CO2
reading
on
the
SEU
settles
consistently
at
or
near
4%
CO2
on
the
screen.
4.
Both
Alarm
1
and
Alarm
2
will
sound.
5.
Press
the
Mode
button
until
the
“CALI”
icon
flashes.
6.
Press
Enter
2
times
to
enter
the
“SPAn”
calibration
mode.
The
“CALI”
icon
and
“SPAn”
should
be
displayed
on
the
screen.
7.
Press
and
hold
the
Mode
button
for
at
least
10
seconds
until
“Calibrating”
and
“CO2”
are
flashing
simultaneously.
8.
Span
calibration
will
begin.
After
approximately
5
minutes,
the
LCD
will
display
either
“PASS”
or
“FAIL”.
If
the
LCD
reads
“FAIL”,
repeat
the
steps
again.
9.
Press
Enter
to
complete
calibration.
Remove
the
CO2
cylinder.
10.
To
reset
the
alarm,
you
must
disconnect
the
SEU
from
the
power
source.
Wait
a
few
seconds,
then
plug
it
back
in
again.
If
your
unit
fails
either
“ZEro”
or
“SPAn”
calibration,
please
follow
the
procedure
again
before
calling
support.
