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Table 9. Heat Pump Parameters
Parameter Description
Defrost Termination
Temp
(Single and Two-Stage
Lennox Communicating
Heat Pump Units)
This is the temperature that defrost mode will be terminated. In dual
fuel applications (furnace and heat pump), defrost tempering is
automatically enabled and operates as follows:
• Furnace will run for 75 seconds ON then after 90 seconds OFF
for two cycles.
• After the rst two cycles, the furnace will run for 60 seconds ON
then cycle OFF for 90 seconds.
• This cycle will be repeated unit the room thermostat is informed
by the outdoor control that defrost has terminated.
The range is 50 - 100°F (10.0 to 37.78°C). Default is 50°F (10.0°C)
and with an incremental adjustment of 10°F (5.56°C).
Variable capacity - Both Furnace and
Heat Pump are Modulating:
When the thermostat receives information that the heat pump
has entered defrost the thermostat sends a minimum rate heating
demand to the furnace. Then the thermostat terminates the
minimum rate heating demand upon defrost completion or any time
the heat pump stops. (i.e., pressure switch opens, mode switch
changes, etc.)
Staged – Both Furnace and Heat Pump are Multi-Stage:
When the thermostat receives information that the heat pump has
entered defrost the thermostat performs the following :
• Sends a rst stage heating demand to the furnace.
• After 75 seconds elapse from the time the rst stage demand
was sent, the thermostat terminates the furnace heating demand.
• After the furnace minimum off time has elapsed (90 seconds)
from the time the previous heating termination, the thermostat
starts rst stage furnace heat again by sending the rst stage
heating demand. This is the new adjustable gas heat delay
setting for zoning.
• After 60 seconds elapse from the previous heating demand being
sent, the thermostat terminates the furnace heating demand.
• Repeat steps 3 and 4 while defrost is active, terminating any
running furnace heat demand when the HP indicates that defrost
is no longer active or any time the heat pump stops. (i.e., pressure
switch opens, mode switch changes, etc.)
NOTE: The on times above assume the minimum furnace ignition
time of 35 seconds.
Dehum Airow
Adjustment Adder
(Lennox Variable
Capacity Heat
Pumps Only)
Dehumidication airow = HUMID Mode CFM table value for a given
thermostat demand + dehumidication adjustment adder (High
Normal Cooling Airow CFM x Dehumidication Airow Adjustment
Adder in percentage.
Both these values are in the installer set up under dealer control
center > equipment > heat pump. Range is 0 to 30%. Default is
28%.
NOTE: Deactivated in auxiliary dehumidication and enhanced
dehumidication accessory (Humiditrol)
Table 9. Heat Pump Parameters
Parameter Description
Equipment Name
A unique name can be assigned to this component. Name can be
up to 29 characters. Name can consist of letters, numbers, special
characters and spaces.
High Normal
Cooling Airow
(Lennox Variable
Capacity Heat
Pumps Only)
Thermostat values shown are defaults. This value can be adjusted
up or down to meet each application requirements.
The range is 450 - 2150 CFM. Default is dependent on unit capacity
with an incremental adjustment of 25 CFM.
Fan Cycling
(Single and Two-Stage
Lennox Communicating
Heat Pumps)
Options are ON or OFF. Default OFF.
High Normal HP
Heating Airow
(Lennox Variable
Capacity Heat
Pumps Only)
Thermostat values shown are defaults. This value can be adjusted
up or down to meet each application requirements.
The range is 450 - 2150 CFM. Default is dependent on unit capacity
with an incremental adjustment of 25 CFM.
Low Normal
Cooling Airow
(Lennox Variable
capacity Heat
Pumps Only)
Thermostat values shown are defaults. This value can be adjusted
up or down to meet each application requirements.
The range is 450 - 2150 CFM. Default is dependent on unit capacity
with an incremental adjustment of 25 CFM.
Low Normal HP
Heating Airow
(Lennox Variable
Capacity Heat
Pumps Only)
Thermostat values shown are defaults. This value can be adjusted
up or down to meet each application requirements.
The range is 450 - 2150 CFM. Default is dependent on unit capacity
with incremental adjustment of 25 CFM.
Max Defrost by
Weather
(Single and Two-Stage
Lennox Communicating
Heat Pump Units)
Options are off and on. Default is off. When set to on, information
from the default Internet weather source is used to determine when
Max Defrost is used.
Reset Heat Pump
Any installer modications under the heat pump tab will be reset
back to the factory defaults if the reset heat pump option is used.
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