Fujitsu FO2416RTJNAA - Page 31

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6.0 SEQUENCE OF OPERATION
Operation
Defrosting of the outdoor coil in the heating mode
is controlled by the defrost control located in the
outdoor unit. TZPLD16 heat pumps feature “de-
mand defrost” that initiate a defrost cycle only
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heating operation. The defrost control monitors
the Outdoor Ambient Temperature Thermistor and
Outdoor Coil Temperature Thermistor to determine
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࠮ +LMYVZ[0UP[PH[PVU! A defrost cycle is initiated
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[1.7°C].
2. The compressor has operated for at least
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3. The defrost control determines a defrost
cycle is required based on the outdoor
ambient and outdoor coil temperatures.
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and the outdoor fan motor is de-energized.
2. The compressor is de-energized for a 30
second noise abatement period.
3. The indoor air-handler or gas furnace is
directed to supply supplemental heat to
prevent cold air from being discharged
from the supply registers during the defrost
cycle.
4. The compressor is energized after the 30
second delay has been completed and
defrosting of the coil begins.
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continue until the coil temperature has reached
the termination temperature or 14 minutes
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factory default termination temperature is 70°F
[21.1°C], although this temperature can be
changed to 50°F [10.0°C], 60°F [15.6°C], or
80°F [26.7°C] by relocating a jumper on the
defrost control board. When the coil tempera-
ture reaches the termination temperature or 14
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2. The compressor is de-energized for a 30
second noise abatement period.
3. Supplemental heat is de-energized.
4. The compressor and outdoor fan motor are
energized after the 30 second delay has
been completed.
5. The system returns to normal heating oper-
ation as directed by the thermostat.
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-B-D
See Section 7.1 (Demand Defrost Control) for addi-
tional information.
6.5 Demand Defrost