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• After a five 5 minute delay the system will begin operations to satisfied the
cooling demand from zone 2.
The system will continue to operate in this matter each time it receives a zone
call that is opposite of the current mode of operation (heating or cooling).
Damper Operation
Cooling Operation Conventional Heat/Cool and Heat Pump Systems
When a zone thermostat makes a demand for cooling, the zone damper opens
and the cooling equipment begins operating. Cooling demand is terminated
when:
1. All zone demands for cooling are terminated.
2. The demand has exceeded the heat/cool changeover time limit (20
minutes) while a heat demand exists.
When cooling demand is terminated, a 5 minute minimum off time delay is
initiated.
Second stage cooling is energized when the discharge air temperature is 7°F
higher than the set point of the cooling staging temperature settings.
Heating Operation Conventional Heat/Cool and Heat Pump Systems
When a zone thermostat makes a demand for heating, the zone damper opens
and heating equipment begins operating. Heating demand is terminated when:
1. All zone demands for heating are terminated.
2. The demand has exceeded the heat/cool changeover time limit (20
minutes) while a cooling demand exists.
When heating demand is terminated, a 5 minute minimum off time delay is
initiated. Second-stage heating is energized if the discharge air temperature is
lower than the set point of the heating staging temperature set point.
Dual-Fuel Operation
NOTE: A 10T50 Interface Module is required for non-communicating dual-fuel
applications.
When both a gas furnace and a heat pump are present on the system, the
thermostat uses the balance points to determine which source to use for
heating.
When the outdoor temperature is above the low balance point, the heat pump
is always attempted first before using the gas furnace.
In order to use the gas furnace as a primary heating source (not defrost
tempering) when the outdoor temperature is between the high and low balance
points, the following conditions must occur:
• Heat pump must be used for a minimum of 30 minutes.
• Temperature in the zone not increase by more than 0.5°F
• Heat pump has not gone into defrost in the 30 minute period
If any single-zone satisfies the specified conditions, the heat pump will stop
and the gas furnace is used to satisfy all heat calls for the next duration of the
parameter heat pump lockout time. After the heat pump lock out has expired,
the heat pump is again used as the primary heat source on the next call after
the equipment has stopped.
Emergency Heat Operation - Heat Pump Systems
When the Lennox communicating thermostat emergency heat is enabled the
unit will satisfy all heating demand with either gas or electric backup heat.
When the Emergency Heat setting is OFF, the heat pump is used to satisfy
heating demands.
Humidity Control
Refer to Lennox communicating thermostat installation and setup guide for
more information on humidity control settings and operating modes.
Note, there no controls modes, while in zoning mode, to actively humidify or
dehumidify, to obtain a certain dew-point or relative humidity.
Various control modes to actively humidify or dehumidify would be available
when the iComfort S30 or iComfort Wi-Fi are switched to whole-home mode
(non-zoning).
Soft Disable
Soft disabling is when the Lennox communicating thermostat finds an un-
known control on the S30 system communication bus. The thermostat sends
the unknown control a message to go into soft disable mode until the compo-
nent is properly configured or removed.
Sometimes soft disable will occur when a control is being replaced. Reconfig-
uring the system should resolve this issue.
The Lennox communicating thermostat will not show a alert code for a soft
disabled control. When soft disabling occurs only the control that has been
disabled will display the blinking LED status or seven-segment display indica-
tor. Refer to the device's installation and setup guide for further guidance.
The iComfort control with the soft disable state will indicate so as follows:
• On air handler, integrated furnace and outdoor controls, the soft disable state
is display by double horizontal lines on seven segment display.
• On iHarmony damper control module the green LED will blink 3 seconds on
and 1 second off.
• Soft disable may occur when a control has been replaced. Reconfiguring the
system should resolve this issue.
• Sometimes Lennox communicating thermostat detects a new device or an
existing device or a device on the system that is not communicating with the
thermostat. If this occurs, an alert code 10 is activated and the thermostat
22
Possible Cause
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