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A
PD MANUAL
IOM-39
19 of 36
Aug 99 R1
OPERATION
Warning:
This
unit
is
connected
to
high
voltages.
Electrical
shock
or
death
could
occur
if
instructions
are
not
followed.
This
equipment
contains
moving
parts
that
can
start
unexpectedly.
Injury
or
death
could
occur
if
instructions
are
not
followed.
All
work
should
be
performed
by
a
qualified
technician.
Always
disconnect
and
lock
out
power
before
servicing.
DO
NOT
bypass
any
interlock
or
safety
switches
under
any
circumstances.
Warning:
Proper
commissioning
and
start
‐
up
of
the
air
handling
system
is
the
responsibility
of
the
installing
contractor.
It
is
recommended
that
an
air
balance
be
completed
by
a
certified
air
balancing
contractor
to
insure
the
air
volume
being
delivered
matches
the
unit
rating
plate.
Failure
to
perform
a
proper
air
balance
can
cause
injury
or
death,
damage
to
the
equipment,
property
damage,
system
operational
problems,
or
be
a
cause
of
poor
air
quality.
Moisture
carry
over
can
result
from
improper
air
flow.
This
unit
may
incorporate
one
or
more
functions
and
a
variety
of
controls
and
options
to
suit
individual
requirements.
A
description
of
the
unit
functions
and
options
is
shown
on
the
Electrical
Data
Sheet
and
unit
wiring
diagram.
Carefully
check
your
wiring
diagram
to
verify
that
all
remote
controls
are
properly
located
and
correctly
field
wired.
Dehumidification
systems
first
cool
the
air
with
an
evaporator
coil
operating
below
the
dew
point
temperature,
at
which
time
moisture
is
removed.
The
cool
air
is
then
reheated
back
to
the
required
supply
air
temperature.
Reheat
is
generally
accomplished
using
a
second,
parallel,
internal
condensing
coil
to
provide
the
necessary
amount
of
reheat.
In
some
cases,
a
secondary
heat
source
may
be
used
to
reheat
the
air
i.e.
electric
or
gas
fired
heat
exchanger.
Condenser
reheat
systems
may
employ
either
a
switched
or
modulating
control
system.
Excess
heat
may
be
removed
using
the
outside
condenser,
and/or
a
pool
water
heat
exchanger,
depending
on
the
system
arrangement.
Some
equipment
may
contain
programmable
unitary
controllers
or
programmable
logic
controllers
(PLC).
Additional
information
can
be
obtained
from
the
specific
programmable
control
manufacturer.
Often
this
information
is
available
from
the
control
manufacturer’s
website.
COOLING
COMPONENTS
Refer
to
the
wiring
diagram
and
unit
function
for
specific
information.
Standard
pressure
control
settings
are
found
on
page
34
and
the
following
notes.
Application
specific
control
settings
are
noted
on
the
wiring
diagram
and
in
the
unit
function.
1.
Hermetic
Compressors:
a.
Low
Pressure
Controls:
All
compressors
have
an
auto
‐
reset
low
pressure
control
with
contacts
that
open
at
low