Lennox Hearth 502, 862M User Manual
What Is the Harmony IIR Zone Control System?
Lennox Harmony IIR Zone Control System manages the distribution of conditioned air to as many as four
specific areas or zones in a home or small commercial building. The Harmony II
control system that allows a home to be zoned for heating and cooling without the extra expense of purchasing two or more HVAC (Heating, Ventilation, and Air Conditioning) systems.
This control allows the owner to heat or cool occupied areas without conditioning unused areas, resulting in lower utility bills. This control orchestrates the system components to provide a balanced
and comfortable environment.
The system consists of the control panel and the control center. The Harmony II control panel is your
link to a comfortable enviroment. The control panel is usually located near the main or master thermostat. The control center is the larger control box and is the brains" of the Harmony II
organizes the operations of the thermostats, dampers, and HVAC equipment to result in total com-
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fort. The Harmony II
1 − Pulse21
TM V" series gas furnace and either a single− or two− speed condensing unit; Option 2 −
system operates with any of the following HVAC system combinations: Option
CB21 series blower coil unit and either a Lennox single− or two− speed heat pump; or Option 3 −
Pulse21 V" series gas furnace, a Lennox heat pump, and the FM21 control. Harmony II
trol system uses off−the−shelf thermostats and dampers with any of the above systems to distribute
conditioned air to zones.
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control Is an advanced
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system. It
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zone con-
How Are Zones Determined?
Your Lennox dealer has sectioned the rooms of your home or building into zones using the below
considerations.
Structural/Architectural Considerations
In multi−level houses using regular HVAC systems, heated air rises to the upper floor(s) causing those
rooms become too hot. Zoning will remedy this situation by splitting the conditioned space into two
specific zones (first and second floors). The second floor temperature is now controlled by its own thermostat, not that of the first floor.
Climate Considerations
Exposure from the sun and weather can produce cold and hot spots in homes that are conditioned
with the use of one thermostat. Zoning lessens this by grouping rooms with the same exposure into
one zone. Therefore, a room with a northern exposure and a room with a southern exposure should
not be zoned together. In the winter, the northern room may be too cool while the southern room may
be too hot. In order to keep a balance of conditioned air, the zone must contain rooms with the same
weather exposure.
Occupancy Considerations
A single structure contains different types of living spaces. Without zoning, it is difficult to condition all
areas so that everyone will be comfortable. Zoning a home or office allows the owner to control the
zones which need to be conditioned. Rooms that are used or occupied at the same time are zoned together. Bedrooms which are generally used at night, should not zoned with a living room that is used only
during the day or evening.
Harmony II® User’s Manual
Page 1
502,862M
02/2000
Using the Harmony II® Control Panel
The Harmony IIR control panel is where the control center gets its information on how to operate. It
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works with the thermostats to provide a desired comfort level for each zone. The Harmony II
panel uses LEDs (light emitting diodes) to display the current operating mode.
The Harmony II
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system operates in either of two modes: Central mode or Zone mode. In Central
mode, all zones receive conditioned air at the same time, just like a traditional heating and air conditioning system. The master thermostat located in zone 1 controls any heating or cooling need for the
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entire building. When the Harmony II
system is placed in Zone mode, specific zones are condi-
tioned only when the demand comes from that zone. Notice that each zone, not each room, has its
own thermostat. These thermostats only work when the control panel is in Zone Mode. The System
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Off button will turn off the Harmony II
control.
The Heat, Cool, and Auto buttons on the control panel tell the control center what type of air to provide and are available in Central and Zone modes. Select one operation (Heat, Cool or Auto) at a
time. The Heat selection, tells the control center that it should provide heat to the zones when it is
needed. The Cool selection, in turn, tells the control center to provide cool air to the zones when
there is a need. The Auto selection is the most flexible choice since it allows either heating or cooling
to occur, depending on the need. This selection is particularly nice in times of seasonal changes. For
example, in the spring, the temperature is cool in the morning and warm in the afternoon. By placing
the control panel and thermostats in Auto, heating will come on in the morning and cooling in the
afternoon, if needed.
control
The Fan Auto and Fan On buttons on the control panel tell the control center how the blower should
operate. Select one operation (Fan Auto or Fan On) at a time. Fan Auto allows the blower to cycle on
and off with the heating or cooling needs. The Fan On selection allows the blower to run continuously. To stop the blower, press the Fan Auto button.
Service Light
A red LED, visible only when an error occurs, indicates an error condition has been logged in the
control center and either the inside unit or zone control system requires service. Alert your Lennox
service technician that the Harmony II
the light is lit steadily or if it flashes off and on. DO NOT try to diagnose error codes or repair control
panel. The control center must be handled by qualified service technicians only. Tampering with control center may result in electrical shock and damage to the control center.
NOTE − The service light located in the master thermostat (heat pumps only) provides a separate
function indicating the outdoor unit requires service. The service light in zone 2, zone 3 and zone 4
thermostats is not functional. Call your Lennox service technician if the service light on the zone 1
thermostat is lit.
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control panel service light is on. Also inform the technician if
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