507343-01
Page 32
Defrost Operations
This section is applicable only to heat pumps that are using outdoor control part number 103369-03 or higher.
System Devices
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To adjust a setting, highlight it,
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1b
edit
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Humidification Control Mode
current value:
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Basic
Configure the device as follows:
1. In the system devices list, use the arrows (1a) to highlight
Heat Pump. Press edit (1b).
2. In the Heat Pump list, use the arrows (2a) to highlight the
desired option. Press edit (2b).
2a
2b
System
Heat Pump
Furnace
Thermostat
Power (120VAC) Humidifier
Heat Pump
Equipment Name
Compressor Short Cycle Delay
Defrost termination Temp
Automatic Max Defrost
Max Defrost by Weather
Compressor Shift Delay On/Off
Control Mode
Figure 38. Adjust Defrost Settings
DEFROST TERMINATION TEMPERATURE
1. The Defrost Termination Temp parameter factory
default is 50°F (10°C). This setting can be changed to
terminate defrost at 70°F, 90°F or MAX (21°C, 32°C and
MAX).
NOTE Colder climates may require a higher defrost
termination temperature to maintain a clear coil.
2. If the parameter is set to MAX, defrost will run maximum
defrost sequence.
AUTOMATIC MAX DEFROST
These features are only available when the heat pump outdoor
control part number is 103369-03 or later. See figure 40 for the
sequence of operations for Automatic Max Defrost.
1. Defrost Auto can be set to either ON or OFF. Factory
setting is OFF.
Note: If the jumper is missing the default is OFF.
2. Defrost Auto is set to OFF, the defrost cycle will run and
terminate based on Defrost Termination Temperature
setting.
3. Defrost Auto is set to ON, the defrost termination will be
determined based on the following rules:
A.. The first defrost after the unit is powered up, or the
first defrost after cooling call will terminate based on
the Defrost Termination Temperature setting.
B.. The accumulated heating runtime between defrost
cycles:
If the heating run time between defrost cycles
is less than 50 minutes, the defrost termination
temperature will be increased for the next defrost
cycle based on the current termination setting. If
the current termination setting is 50ºF or 70ºF,
then the next defrost termination will be 90ºF. If
the Defrost Termination Temperature setting is
set at 90ºF or MAX, the next defrost cycle will
terminate at the MAX setting.
If the heating run-time between defrosts is
longer than 1 hour for 2 consecutive heating
cycles and the defrost termination temperature is
set at 50ºF, 70ºF, or 90ºF, then the defrost control
will follow the Defrost Termination
Temperature setting during the next defrost
cycle. If the Defrost Termination Temperature
setting is set to MAX, then the next defrost
termination temperature will be decreased to
90ºF.
C..If Defrost Termination Temperature setting is set to
MAX, the system will always run at MAX when
accumulated compressor OFF time is longer than 30
minutes and ambient temperature is less than
35°F.
D.. When the ambient sensor temperature is higher
than 40ºF and Defrost Termination Temperature
setting is set to MAX, defrost termination will be 90ºF.
If Defrost Termination Temperature setting is 50ºF,
70ºF, or 90ºF, defrost termination will follow the
Defrost Termination Temperature setting.
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