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COMPRESSOR
OPERATION
When the compressor
is operating
in low stage, the modulating
ring is de-activated,
allowing
two internal
bypass
ports to close
off 33% of the scroll
compression
area so the system
operates
at
part load capacity.
The 24-volt
solenoid
coil is de-energized
in
low-stage
operation.
When the compressor
is operating
at high stage, the modulating
ring
is activated,
sealing
the bypass
ports,
which
allows
the
compressor
to operate
at full load capacity.
The 24-volt
solenoid
coil is energized
in high stage operation.
CRANKCASE
HEATER
OPERATION
(IF APPLICABLE)
The crankcase
heater
is energized
during
off cycle below
65°F
outdoor
air temperature.
OUTDOOR
FAN MOTOR
OPERATION
The outdoor
unit control
energizes
the outdoor
fan any time the
compressor
is operating.
The outdoor
fan remains
energized
if a
pressure
switch or compressor
overload
should open. Outdoor
fan
motor
will
continue
to
operate
for
one
minute
after
the
compressor
shuts off when the outdoor
ambient
is greater than or
equal to 100°F.
TIME DELAYS
The unit time delays include:
•
Five minute
time delay to start cooling
operation
when there
is a call from the thermostat
or UI. To bypass
this feature,
momentarily
short and release Forced
Defrost pins.
•
Five
minute
compressor
re-cycle
delay
on return
from
a
brown-out
condition.
•
Two minute
time delay to return to standby
operation
from
last valid communication
(with Infinity
only).
•
One minute
time
delay
of outdoor
fan at termination
of
cooling
mode when outdoor
ambient
is greater
than or equal
to 100°F.
•
There is no tinm delay between
staging from low to high and
from high to low capacity;
the compressor
will change from
low to high and from high to low capacity
as demand
dictates.
INFINITY
CONTROLLED
LOW AMBIENT
COOLING
NOTE:
When
this
unit
is operating
below
55°F
outdoor
temperature,
provisions
must be made for low ambient
operation.
This unit is capable
of low ambient
cooling
ONLY when using the
Infinity control.
A low ambient
kit is not required,
and the outdoor
fan motor does not need to be replaced
for Infinity
controlled
low
ambient
operation.
Low ambient
cooling
must
be enabled
in the
UI set-up.
Fan may not begin to cycle until about 40 ° F OAT. Fan
will cycle based
on coil and outdoor
air temperature.
Infinity
controlled
low ambient
mode operates
as follows:
•
In high stage, fan is off when outdoor
coil temp is <(outdoor
air temperature
+3°F)
or outdoor
fan has been ON for 30
minutes.
(Fan is turned
off to allow
refrigerant
system
to
stabilize.)
•
In low stage, fan is off when outdoor
coil temp is <(outdoor
air temperature
+I°F)
or outdoor
fan has been ON fnr 30
minutes.
(Fan is turned
off to allow
refrigerant
system
to
stabilize.)
•
In high stage and low stage, fan is on when outdoor coil temp
> (outdoor
air temperature
+25°F)
or outdoor
coil temp >
80 °F or if outdoor
fan has been OFF for 30 minutes.
(Fan is
turned on to allow refrigerant
system to stabilize.)
•
Low-pressure
switch is ignored for first 3 minutes
during low
ambient
start up. After 3 minutes,
if LPS trips, then outdoor
fan motor is turned off for 10 minutes,
with the compressor
running.
If LPS
closes
within
10 minutes
then
cooling
continues
with
the
outdoor
fan
cycling
per
the
coil
temperature
routine
listed
above
for the remainder
of the
cooling
cycle. If the LPS does not close within 10 minutes,
then
the
normal
LPS
trip response
(shut
down
cooling
operation
and generate
LPS trip error) will occur.
Step 3--Check
for Refrigerant
Leaks
Locate and repair refrigerant
leaks and charge the unit as follows:
1. Use both high-
and low-pressure
ports to relieve
system
pressure
and reclaim
remaining
refrigerant.
2. Repair leak following
accepted
practices.
NOTE:
Install a filter drier whenever
the system has been opened
for repair.
3. Check system
for leaks using an approved
method.
4. Evacuate
refrigerant
system
and reclaim
refrigerant
if no
additional
leaks are found.
5. Charge
unit
with
Puron
(R-410A)
refrigerant,
using
a
volumetric-charging
cylinder
or accurate scale. Refer to unit
rating plate fnr required
charge.
Step 4_Start-Up
Adjustments
Complete
the
required
procedures
given
in the
Pre-Start-Up
section before starting
the unit. Do not jumper
any safety devices
when
operating the unit. Do not operate
the unit in cooling
mode
when the outdoor temperature
is below 40°F (unless low-ambient
operation is enabled
in the UI). Do not rapid cycle the compressor.
Allow
5 min. between
"on" cycles
to prevent
compressor
damage.
CHECKING
COOLING
AND
HEATING
CONTROL
OPERATION
See UI Installation
Instructions
for detailed
system
CHECKOUT.
CHECKING
AND ADJUSTING
REFRIGERANT
CHARGE
The
refrigerant
system
is fully
charged
with
Puron
(R-410A)
refrigerant
and is tested and factory
sealed.
NOTE:
Any adjustment
to refrigerant
charge
must be done with
unit operating
in HIGH stage.
NOTE:
Adjustment
of the refrigerant
charge is not required
unless
the unit is suspected
of not having the proper
R-410A
charge.
The
charging
label and the tables shown refer to system temperatures
and
pressures
in cooling
mode
only. A refrigerant
charging
label
is
attached
to the outside
of the unit.
IMPORTANT:
When
evaluating
the
refrigerant
charge,
an
indicated
adjustment
to the specified
factory charge must always be
very minimal.
If a substantial
adjustment
is indicated,
an abnormal
condition
exists
somewhere
in the
cooling
system,
such
as
insufficient
airflow across either coil or both coils.
REFRIGERANT
CHARGE
The amount
of refrigerant
charge
is listed on the unit rating
plate
and/or the physical
data table. Refer
to the Refrigeration
Service
Techniques
Manual,
Refrigerants
Section.
NO CHARGE
Check
for
leak.
Use
standard
evacuating
techniques.
After
evacuating
system,
weigh
in the specified
amount
of refrigerant
(refer to system
rating plate).
LOW CHARGE
COOLING
Use Cooling
Charging
(;hart
(Fig. 18). Vary refrigerant
until the
conditions
of the chart
are met. Note
that
charging
charts
are
different from type normally
used. (;harts are based on charging
the
units to correct
subcooling
for the various
operating
conditions.
Accurate
pressure
gauge
and temperature
sensing
devices
are
required.
Connect
the pressure
gauge
to the service port
on the
suction
line. Mount the temperature
sensing
device
on the suction
line and insulate
it so that the outdoor
ambient
does not affect the
reading. Indoor air CFM must be within the normal operating
range
of the unit.
18
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