HD755-EU-EN V1.7 7/13
4
Basic
Operation
Meter
Power
The
HD755
uses
a
9V
battery
for
power.
If
the
meter
does
not
switch
on
when
the
POWER
button
is
pressed
or
if
the
display
shows
BAT
,
replace
the
battery.
When
the
POWER
buttons
is
pressed,
the
meter
performs
a
short
self
‐
test
and
reverts
to
the
settings
in
place
when
the
meter
was
last
turned
off.
Automatic
Power
‐
off
Feature
In
order
to
conserve
battery
life,
the
meter
has
an
automatic
power
off
feature
(after
20
minutes).
To
defeat
this
feature,
press
and
hold
the
HOLD
button
while
turning
the
meter
on.
Release
the
HOLD
button
when
‘n’
appears
on
the
display.
The
meter
will
now
remain
on
until
the
user
turns
it
off
or
until
the
battery
weakens.
Note
that
the
Auto
Power
OFF
feature
will
be
reactivated
the
next
time
the
meter
is
turned
off
and
then
on.
Unit
of
Measure
Press
the
UNIT
button
to
select
the
unit
of
measure.
This
meter
offers
eleven
(11)
units
of
measure
as
listed
below.
Unit
of
Measure
Display
icon
Pounds
per
square
inch
psi
Inches
of
Mercury
inHg
Milli
‐
bar
mbar
Millimeters
of
Mercury
mmHg
Kilo
‐
Pascals
kPa
Kilograms
per
centimeter
squared
Kgcm
2
Inches
of
water
inH
2
O
Feet
of
water
ftH
2
O
Centimeters
of
water
cmH
2
O
Bars
Bar
Ounces
per
square
inch
ozin
2
Fittings
Connection
Connect
tubing
to
the
P1,
P2
(or
both)
input
port(s).
If
both
inputs
are
used
(differential
mode),
the
meter
displays
a
positive
pressure
reading
if
the
P1
pressure
is
greater
than
P2
and
a
negative
reading
if
P2
is
greater
than
P1.
