A
PD MANUAL
IOM-39
23 of 36
Aug 99 R1
3.
Extended
Shutdown
Note:
Leaving
the
main
power
on
will
keep
the
crankcase
heaters
energized
and
will
not
harm
the
system.
4.
Re
‐
Start
After
Extended
Shutdown
a)
If
the
main
power
was
off,
re
‐
connect
main
power
and
allow
24
hours
for
crankcase
heaters
to
work
prior
to
start
‐
up
of
compressors.
b)
If
main
power
was
left
on,
check
to
ensure
the
crankcase
heaters
are
still
operating.
If
not,
replace
them
and
allow
at
least
24
hours
before
starting
the
compressor.
c)
Follow
the
steps
in
the
initial
start
‐
up
procedure.
CHARGING
INSTRUCTIONS
Charging
a
system
should
be
done
at
design
conditions.
Refer
to
the
submittal
record
for
details.
Condenser
air
flow
can
be
temporarily
restricted
to
simulate
this
condition.
The
following
describes
systems
that
do
not
use
a
refrigerant
reheat
coil.
Raise
the
head
pressure
to
a
saturated
discharge
pressure
that
corresponds
to
130°F
(54°C).
Charge
refrigerant
into
the
system
slowly
until
the
system
sight
glass
is
clear.
The
system
must
be
at
design
air
flow
and
load.
If
the
system
is
equipped
with
an
Engineered
Air
Intercooler
sight
glass
only,
raise
the
head
pressure
to
a
value
corresponding
to
130°F
(54°C).
Charge
system
until
the
flash
intercooler
sight
glass
is
clear.
Add
additional
refrigerant
until
the
liquid
line
entering
the
intercooler
is
subcooled
5°F
(2.7°C).
REHEAT SYSTEMS
Reheat
systems
operate
by
controlling
the
flow
of
liquid
refrigerant
(not
gas).
All
circuits
with
an
auxiliary
condenser
(reheat
or
pool
heat
plus
standard
condenser)
will
have
a
receiver.
Subcooling
will
be
accomplished
with
either
a
dedicated
subcooling
circuit
in
the
bottom
of
the
reheat
coil,
or
with
an
Engineered
Air
Intercooler.
The
sight
glass
should
be
clear
of
bubbles
during
stabilized
operation.
When
the
system
switches
modes
from
reheat
to
the
outdoor
coil
or
vice
versa,
it
is
normal
for
the
sight
glass
to
bubble
until
the
system
has
stabilized.
The
sight
glass
may
take
several
minutes
to
stabilize
after
a
mode
change.
BEFORE
ADDING
REFRIGERANT
CHECK
THE
FOLLOWING:
