Carrier Infinity 48XT A Series Installation Instructions Manual page 23

S Five minute time delay to start heat pump cooling or heating
operation when there is a call from the thermostat or user
interface. To bypass this feature, momentarily short and release
Forced Defrost pins.
S Five minute compressor recycle delay on return from a
brown- -out condition.
S Two minute time delay to return to standby operation from last
valid communication (with Infinity only).
S One minute time delay of outdoor fan at termination of cooling
mode when outdoor ambient is greater than or equal to 100_F
(38°C).
S Fifteen second delay at termination of defrost before the
auxiliary heat (W1) is de- -energized.
S Twenty second delay at termination of defrost before the outdoor
fan is energized.
S Thirty second compressor delay when quiet shift enabled.
S There is no time delay between heat pump 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 (12.8_C) outdoor
temperature, provisions must be made for low ambient operation.
This unit is capable of low ambient cooling down to 0_F
(- -17.8_C) 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 (4.4_C). Fan will cycle based
on coil and outdoor air temperature.
ambient mode operates as follows:
S In high stage, fan is off when outdoor coil temp is <outdoor air
temperature plus 3_F (1.7_C) or outdoor fan has been ON for 30
minutes. (Fan is turned off to allow refrigerant system to
stabilize.)
S In low stage, fan is off when outdoor coil temp is <outdoor air
temperature plus 1_F (.6_C) or outdoor fan has been ON for 30
minutes. (Fan is turned off to allow refrigerant system to
stabilize.)
S In high stage and low stage, fan is on when outdoor coil temp >
outdoor air temperature plus 25_F (13.4_C)or outdoor coil temp
> 80_F (26.7_C) or if outdoor fan has been OFF for 30 minutes.
(Fan is turned on to allow refrigerant system to stabilize.)
S 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.
DEFROST
This control offers 5 possible defrost interval times: 30, 60, 90, 120
minutes, or AUTO.
The defrost interval times: 30, 60, 90, and 120 minutes or AUTO
are selected by the Infinity Control User Interface (the dip switches
are not used.)
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Infinity controlled low
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AUTO defrost adjusts the defrost interval time based on the last
defrost time as follows:
S When defrost time <3 minutes, the next defrost interval=120
minutes.
S When defrost time 3- -5 minutes, the next defrost interval=90
minutes.
S When defrost time 5- -7 minutes, the next defrost interval=60
minutes.
S When defrost time >7 minutes, the next defrost interval=30
minutes.
The HP/AC control board accumulates compressor run time. As
the accumulated run time approaches the selected defrost interval
time, the control board monitors the coil temperature sensor for a
defrost demand. If a defrost demand exists, a defrost cycle will be
initiated at the end of the selected time interval. A defrost demand
exists when the coil temperature is at or below 32_F (0_C) for 4
minutes during the interval.
The defrost cycle is terminated when the coil temperature reaches
65_F (18_C) or 10 minutes has passed.
If the coil temperature does not reach 32_F (0_C) within the
interval, the interval timer will be reset and start over.
S Upon initial power up the first defrost interval is defaulted to 30
minutes. Remaining intervals are at selected times.
S Defrost is only allowed to occur below 50_F (10_C) outdoor
ambient temperature.
DEFROST HOLD
Defrost hold is not needed in a communicating system because the
UI will complete the defrost cycle before shutting down the
system.
FORCED DEFROST
Forced defrost is initiated with the UI.
During a Forced Defrost:
S If coil temperature is at defrost temperature of 32_F (0_C), and
outdoor air temperature is below 50_F (10_C), a full defrost
sequence will occur.
S If coil temperature or outdoor air temperature do not meet the
above requirements, an abbreviated 30 second defrost will occur.
QUIET SHIFT
Quiet Shift is a field- -selectable defrost mode which may eliminate
occasional noise that could be heard at the start of the defrost cycle
and restarting of the heating cycle. This feature must be enabled at
the UI. When activated, the following sequence of operation will
occur. Reversing valve will energize and compressor will turn off
for 30 seconds, then turn back on to complete defrost. At the end
of the defrost cycle, the reversing valve de- -energizes, compressor
will turn off for another 30 seconds, and the fan will turn off for 40
seconds, before starting in the heating mode.
DEHUMIDIFICATION MODE
This Infinity system can be used to dehumidify the living space.
See User Interface Installation Instructions for more details.
SEQUENCE OF OPERATION- -GAS HEAT
NOTE: Infinity control must be grounded for proper operation or
control will lock out.
NOTE: If a power interruption occurs during a call for heat, the
control will start a 90- -second blower- -only ON period two seconds
after power is restored, if the UI is still calling for gas heating. The
amber LED light will flash code 12 during the 90- -second period,
after which the LED will be ON continuously, as long as no faults
are detected. After the 90- -second period, the unit will respond to
the UI normally.