HOMEOWNER’S
E2006 Lennox Industries Inc.
Dallas, Texas, USA
MANUAL
Harmony IIIt Zone Control
System
CONTROLS
505,024M
05/06
Supersedes 01/06
IMPORTANT: Read this instruction manual
completely! Retain for future reference.
Contents Page
What Is the Harmony IIIt Zone Control System? 2. .
What does the system consist of? 2. . . . . . . . . . . . . . .
How do I set the control center switches? 2. . . . . . . . .
How do I use the thermostat controls? 4. . . . . . . . . . .
What does the service light indicate? 4. . . . . . . . . . . . .
How do I use the central (Vacation) mode? 4. . . . . . .
How do I use the zone mode? 4. . . . . . . . . . . . . . . . . . .
How are zones determined? 5. . . . . . . . . . . . . . . . . . . .
Thermostat replacement and maintenance 5. . . . . . . .
Homeowner’s Zone Information Record 6. . . . . . . . . .
Litho U.S.A.
05/06 505,024M
*2P0506* *P505024M*
What is the Harmony IIIt Zone Control System?
Lennox Harmony IIIt Zone Control System manages the
distribution of conditioned air to as many as four specific
areas or zones in the home. The Harmony IIIt control is
an advanced 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. The system
adapts the HVAC components to provide a balanced and
comfortable environment.
What does the system consist of?
The principle system component is the control center
which acts as the brains" of the Harmony IIIt zone con-
trol system. It coordinates all of the operations of thermostats, motorized dampers, and HVAC equipment.
Harmony IIIt zone control system uses off-the-shelf
1-heat/1-cool, non-power-robbing, non-heat pump electronic thermostats and motorized dampers with one of the
following Lennox HVAC systems to distribute conditioned
air to zones:
1. Option 1Gas Furnace with Variable Speed Blower
Motor (VSM) and either a single- or two-speed condensing unit.
2. Option 2Blower coil unit with variable speed blower
motor and either a single- or two-speed heat pump.
3. Option 3Gas furnace with variable speed blower
motor and heat pump.
How do I set the control center switches?
The Harmony IIIt control center has only two ON/OFF
switches (see illustration). For the most part, the system
relies on thermostats to provide control of the desired comfort level for each zone. The control center also has LEDs
(light emitting diodes) which light to indicate the current operating mode and which zone dampers are closed.
1. Vacation switchThe Harmony IIIt control center
operates in either of two modes: central mode (Vacation switch ON) or zone mode (Vacation switch OFF).
D Central mode (Vacation ON) − all zones receive
conditioned air at the same time (like traditional,
non−zoned HVAC systems). The master thermostat (located in Zone 1) controls any heating or
cooling need for all zones in the building.
D Zone mode (Vacation OFF) − specific zones are
conditioned only when the demand comes from
that zone. Each zone (not necessarily each room)
has its own thermostat. The individual zone thermostats only work when the control center is in
zone mode.
Page 2
2. Emergency Heat switchWhen the Harmony IIIt
control center is used with a heat pump and the Emergency Heat switch is turned ON, the unit will satisfy all
heating demands with electric backup heat. When the
Emergency Heat switch is OFF, the heat pump is used
to satisfy heating demands. (This switch has no effect
on operation in a non-heat pump system, for example,
Option 1, described on page 2.)
Damper LEDs come on to indicate
Vacation OFF for individual zone control.
Vacation ON for all zones to be conditioned
at the same time.
Emergency Heat OFF to allow Heat Pump
to provide heat.
Emergency Heat ON to force auxiliary
(backup) heat to provide all heating
(disallows heat pump from providing any
heat).
the damper to zone # is CLOSED
(No air being permitted to LIT zone)
LEDs come on to indicate the current operating mode
NOTE − Usually, Emergency Heat is more expensive
to operate than Heat Pump heating. If so equipped,
use Emergency Heat only when necessary.
To turn off the system, either: A − Turn each thermostat to
OFF, or B − Turn the master thermostat OFF and turn the
control center to central (Vacation ON) mode.
ON indicates only Zone 1
thermostat is functional and
Comes on when
Emergency Heat
switch set to ON
controlling air to ALL zones.
Page 3
How do I use the thermostat controls?
Whether in central mode (where only zone 1 thermostat is
functional) or in the zone mode (where all thermostats are
functional), thermostats function as in a traditional, non−
zoned, system. That is:
S HEAT setting tells the control center that it should pro-
vide heat to the zone(s) when it is needed.
S COOL setting tells the control center to provide cool air
to the zone(s) when there is a need.
S AUTO setting allows either heating or cooling to occur,
depending on the need. This selection is best in spring
or autumn, when the temperature is cool in the morning but still warms in the afternoon. By placing the thermostats in AUTO, heating would come on in the morning and cooling in the afternoon, if needed.
S FAN AUTO or FAN ON tells the control center how the
blower should operate. Select one or the other. FAN
AUTO allows the blower to turn on and turn off with the
heating or cooling needs. FAN ON tells the blower to
run continuously. Zone-controlled dampers in the system make it possible to have some zones call for continuous fan (FAN ON) while other zones are set to FAN
AUTO.
What does the service light indicate?
On heat pump systems only, the service light, located on
the master thermostat, indicates that the outdoor unit requires service. The service lights on zone 2, 3 and 4 thermostats are not functional. Call your Lennox service technician if the service light on the zone 1 thermostat is lit.
How do I use the central (Vacation) mode?
When you choose central (Vacation ON) mode, heating
and cooling will affect all zones.
1. Move the Vacation switch on the control center to ON.
2. Choose either HEAT or COOL or AUTO on the master
(zone 1) thermostat.
3. Choose either FAN AUTO or FAN ON on the master
thermostat.
4. Set master thermostat to desired room temperature.
How do I use the zone mode?
When you choose zone (Vacation OFF) mode, heating
and cooling is controlled by specific zone thermostats.
1. Move the Vacation switch on the control center to OFF.
2. Choose either HEAT or COOL or AUTO on each thermostat (thermostats need not be set alike).
3. Choose either FAN AUTO or FAN ON on each thermostat (these may be set differently in each zone).
4. Set thermostats to desired room temperature.
Page 4
How are zones determined?
Your Lennox dealer has sectioned the rooms of your home
or building into zones using the following considerations:
1. Structural and Architectural ConsiderationsIn multilevel 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.
2. Climate ConsiderationsExposure 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.
3. Occupancy ConsiderationsA 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.
OWNER REMINDER! Be sure the system installer has recorded the zoning information in Table 1 on page 6 and
has identified a contact person and phone number in case
of problems.
Thermostat replacement
In the event a thermostat should fail and require replacement, be aware that not all thermostats will work for all systems. Certain types of thermostats, known as power-robbing thermostats, have no C" (common) wire connection
terminal; these can cause unintended system operation
and therefore must not be used. Call your Lennox dealer to
help you identify and install an appropriate thermostat with
a C" terminal.
Maintenance
Once your Lennox Harmony IIIt Zone Control System is
properly installed, no maintenance is required for the control panel’s components. Only standard heating and cooling equipment (HVAC) maintenance is required.
If you experience problems turning the system on to either
heat or cool, the problem may simply be a programmed
time delay, which, in most cases, would expire within 5 to
20 minutes. Such delays are normal and are built-in to assure proper equipment operation.
Page 5
Table 1. Homeowner’s Zone Information Record
Zone number Record which rooms are zoned together and controlled by thermostat #
1
2
3
4
Lennox Dealer:
Contact:
Telephone Number:
Installation Date:
Page 6
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