Lennox Harmony III User manual

04/06 505,023M
*2P0406* *P505023M*
Page 1
E2006 Lennox Industries Inc.
Dallas, Texas, USA
IMPORTANT
LENNOX recommends ONLY Harmony II®and
Harmony IIItZone Control Systems for use with
Variable Speed Blower Motor (VSM) technology.
INSTALLATION
INSTRUCTIONS
Harmony IIItZone Control
System
ZONING
505,023M
04/06
Supersedes 01/06
Table of Contents
Shipping & Packing List 1. . . . . . . . . . . . . . . . . . . . . . . .
Introduction 1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Residential Zone Control System − Field Wiring 2. . . .
System Components 3. . . . . . . . . . . . . . . . . . . . . . . . . . .
Separately-Ordered System Components 3. . . . . . . . .
Install Heating and Cooling Equipment 4. . . . . . . . . . .
Component Installation 4. . . . . . . . . . . . . . . . . . . . . . . .
Blower Speed Adjustment 6. . . . . . . . . . . . . . . . . . . . . .
Zone Control System Jumper Settings 8. . . . . . . . . . .
Common System Component Wiring 12. . . . . . . . . . . . .
Component Specific Wiring 13. . . . . . . . . . . . . . . . . . . . .
System Operation 16. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Operation & Troubleshooting Indicators 18. . . . . . . . . . .
Fault Recall & Time Delay Override 18. . . . . . . . . . . . . .
Time Delays 19. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
New System Start−Up & Checkout 19. . . . . . . . . . . . . . .
Gas Heating Checkout − Single Zone 20. . . . . . . . . . . . .
Gas Heating Checkout − Multiple Zone 20. . . . . . . . . . .
Gas Heating Checkout − Central Control 21. . . . . . . . . .
Heat Pump Heating Checkout − Single Zone 21. . . . . .
Heat Pump Heating Checkout − Multiple Zone 22. . . . .
Heat Pump Heating Checkout − Central Control 22. . . .
Troubleshooting 25. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Diagnostics Codes 25. . . . . . . . . . . . . . . . . . . . . . . . . . . .
Troubleshooting Diagrams 27. . . . . . . . . . . . . . . . . . . . . .
PIAB Calculation Worksheet 30. . . . . . . . . . . . . . . . . . . .
RETAIN THESE INSTRUCTIONS
FOR FUTURE REFERENCE
Shipping & Packing List
Items shipped with the Harmony IIItZone Control System
include:
1 − Zone Control System circuit board
1 − Discharge Air Sensor
Additional items (ordered separately; see requirements on
Page 3) include:
Transformer
Dampers
Thermostats
Balance Point Sensor (56A83)
(For Heat Pump Option)
Pressureswitch: R−22 (21J18); R−410A (51M08)
Introduction
The Lennox Harmony IIItZone Control System manages
the distribution of conditioned air to specific areas or zones
in a house or small commercial building. The system di-
rects heated or cooled air to occupied areas without condi-
tioning unused areas. This control maximizes economy
while providing a balanced and comfortable environment.
The system can be used in any of the following Lennox
HVAC system application options:
1. Variable speed gas furnace and either a single− or two-
stage condensing unit.
2. Variable speed blower coil unit with electric heat and
either a single− or two-stage heat pump or air condi-
tioner.
3. Variable speed gas furnace and heat pump.
Variations on the options described above and included in
this document are: cooling−only, hot water coil, and cooling
system with electric heat applications.
Litho U.S.A.

Page 2
505023M 04/06
The Harmony IIItzone control system uses off−the−shelf,
single-stage, non-heat pump, non−power-robbing elec-
tronic thermostats and motorized dampers in any of the ap-
plications to distribute conditioned air to different zones.
This control allows conditioning of different zones within a
residence while using a single HVAC system.
The zone control system operates in two modes: central
control (vacation mode) or zone control. LEDs indicate
the current operating mode. Based on a demand from the
central control thermostat, the central control mode allows
the heating and cooling system to condition all of the
zones. In this mode, zone 1 thermostat is designated as
the controlling thermostat; other thermostats are not used.
When the system is in the zone control mode, a zone is
conditioned only upon demand. All wiring connections to
the zone control board are made using low voltage, 18
AWG thermostat wire.
The zone control system is ideal for retrofit applications as
well as new construction. The system controls the air vol-
ume, eliminating the need for bypass dampers in most ap-
plications. The homeowner controls the system using
zone thermostats to make comfort settings for each zone.
A programmable thermostat should be used to provide a
specialized heating and cooling sequence. While the sys-
tem is in the zone mode, a programmable thermostat con-
trols the temperature for its particular zone.
Residential Zone Control System − Overview of Field Wiring
COIL
ZONE
DAMPER
VARIABLE
SPEED
FURNACE
OR COIL
BLOWER
ZONE 1 ZONE 2
*ZONE 3 *ZONE 4
POWER
THERMOSTAT
(ZONE 1 or CEN-
TRAL CONTROL
thermostat when
in Vacation Mode)
ZONE
DAMPER
THERMOSTAT
(ZONE)
CONDENSING
UNIT
OR
HEAT PUMP
OUTDOOR
UNIT
ZONE
DAMPER
ZONE
DAMPER
F
ZONE CONTROL
SYSTEM, THERMO-
STAT AND DAMPER
TRANSFORMER
THERMOSTAT
(ZONE)
THERMOSTAT
(ZONE)
NOTE − Zone 3 and zone 4 not available with single-stage outdoor unit.
LEGEND −
AFive wire low voltage  18 ga. minimum
BTwo wire low voltage  18 ga. minimum
CUp to nine wire low voltage  18 ga. minimum
DTwo wire low voltage (single-stage condensing unit) 18 ga. minimum
Three wire low voltage (two-stage condensing unit) 18 ga. minimum
Up to seven wire low voltage (single-stage heat pump outdoor unit) 18 ga. minimum
Up to eight wire low voltage (two-stage heat pump outdoor unit) 18 ga. minimum
ETwo wire low voltage (discharge air sensor) 18 ga. minimum
FTwo wire low voltage  pressure switch (heat pump only)  18 ga. minimum
GTwo wire  18 ga. minimum
OUTDOOR
THERMOSTAT /
BALANCE
POINT SENSOR
ZONE
CONTROL
SYSTEM
BOARD
A
B
B
A
A
B
BB
A
E
C
D
G

Page 3
HARMONY IIITSERIES
System Components
Zone Control System
The Harmony IIItzone control system monitors electrical
signals and directs control signals between thermostats,
dampers, and HVAC equipment (see figure 1).
JUMPERS:
STAGING
TEMP‘
HEATING−−
COOLING−−
AIR
REDUCTION
CONT.−−
HEATING−−
Figure 1
EQUIPMENT
CONNECTIONS
THERMOSTAT
CONNECTIONS
24VAC
CONNECTIONS
PIAB
JUMPERS
SYS Config & E−HEAT JUMPERS
DIAGNOSTIC
LEDS
time
delay
override
FAULT
RECALL
BALANCE POINT
SENSOR
CONNECTIONS
PRESSURE
SWITCH CON-
NECTIONS
DISCHARGE
AIR SENSOR
CONNECTIONS
DAMPER
CONNEC
TIONS
FUSES
SYSTEM OPERATION LEDS
Harmony IIItZone Control Board
Discharge Air Sensor
A discharge air temperature sensor (88K38) monitors the
supply air. This electronic sensor’s probe (see figure 2) is
inserted into the discharge air plenum to gather air temper-
ature data for the zone control board.
Discharge Air Sensor (Probe)
Figure 2
Separately-Ordered System Components
Thermostats
For all zones, use thermostats that are of this type:
Selectronic thermostat
Ssingle-stage
Snon-heat pump
Snon-power robbing
Sautochangeover or non−autochangeover
Lennox recommends that zone 1 thermostat [central
(vacation) mode controller] be programmable. Each ther-
mostat must have a dead band between HEAT and COOL.
IMPORTANT
Use only Electronic thermostats. Mechanical or
electro-mechanical thermostats will not work with
the Harmony IIItzone control system.
Recommended thermostats include:
SSignatureStattThermostat − 1 heat / 1 cool (81M26)
[IMPORTANT! When using this thermostat, only Pre-
cision Mode dehumidification can be used wherein
2°F of over-cooling is allowed. Also, it cannot reduce
the blower speed because the zone control DS con-
trols the blower. Thermostat D terminal is not used.
SElite®Touch Screen Thermostat − 1 heat / 1 cool /
7−day programmable (X4146).
Transformer
The dampers, zone control board, and zone thermostats
are powered by a single, field−provided 24VAC transform-
er. Together, the zone control panel and thermostats re-
quire 10VA; dampers require 10VA each. The transformer
must have an adequate VA rating to serve all components
(see recommendations in table 1).
Table 1
24VAC Transformer Selection Chart
Catalog
No.
Size Description VA LOAD =
Panel plus−
10P17 40VA 120/208/240VAC, 24VAC 3 dampers
10P87 50VA 120/208/240VAC, 24VAC 4 dampers
12P61 75VA 120/208/240VAC, 24VAC 6 dampers
83P74 _ Electrical Box (4-in.
square)
Dampers
Motorized 24VAC powered closed/spring return open
dampers are standard for the Harmony IIItzone control
system. However, power-open/spring-close" and power-
open/power-close" dampers can be accommodated.
Pressure Switch
A pressure switch [R−22 (21J18); R−410A (51M08)] is re-
quired for applications with a Lennox heat pump (Options 2
and 3). The pressure switch acts as a guard in case of high
head pressures during first− and second−stage heating.

Page 4
505023M 04/06
Balance Point Sensor (Outdoor Thermostat)
A balance point sensor (56A83, shown in figure 3) may be
implemented in a dual-fuel (Option 3) system. This ther-
mostat monitors the outdoor temperature, compares it to
the balance point setting, and signals the zone control if the
reading is below the set point. The zone control then
instructs the gas furnace to provide all the heating and pro-
hibits the heat pump from attempting to fill a demand for
heat.
Figure 3
Balance Point Sensor
Install Heating and Cooling Equipment
The total HVAC system must be properly proportioned to
provide the best comfort. Follow all equipment installation
instructions provided with each unit.
IMPORTANT
LENNOX recommends ONLY Harmony II®and
Harmony IIItZone Control Systems for use with
Variable Speed Blower Motor (VSM) technology.
Option 1 − Lennox Gas Furnace with Variable
Speed Blower Motor (VSM)
& Lennox Condensing Unit
1. Lennox Gas Furnace with VSMThe VSM allows the
zone control system to distribute the amount of air that
goes to each zone. These are the only furnaces avail-
able that work with the Harmony IIItzone control sys-
tem.
2. Lennox Condensing UnitUse condensing units as
shown in table 2.
Table 2
Condensing Units / Heat Pump Units
No. of
zones
Comparative
Zone sizes
Lennox Condensing
Unit or Heat Pump
2 Equal Single or Two−stage
2 Unequal Two-stage only
3 or 4 Equal or Unequal Two-stage only
Option 2 − Lennox Blower Coil Unit with VSM
& Lennox Heat Pump
IMPORTANT
LENNOX recommends ONLY Harmony II®and
Harmony IIItZone Control Systems for use with
Variable Speed Blower Motor (VSM) technology.
1. Lennox Blower Coil Unit with VSMUse ONLY blower
coil units equipped with a variable speed blower motor;
other type of units will not allow the Harmony IIItzone
control system to proportion the amount of air going to
each zone.
2. Lennox Heat Pump UnitUse Heat Pumps as shown
in table 2.
Option 3 − Lennox Gas Furnace with VSM
& Lennox Heat Pump
1. Lennox Gas Furnace with VSM[As described in Op-
tion 1].
2. Lennox Heat Pump Unit[As described in Option 2].
Zone Control Components Installation
Zone Control Board
Select an installation site for the Harmony IIItboard con-
sidering the following location parameters:
SIs conveniently accessible and centrally located to fa-
cilitate wiring from thermostats, dampers, pressure
switch (if used), and HVAC equipment.
SIs in a non−condensing area (such as a closet).
SIs NOT in a laundry room (nor other room in the house
where the humidity would typically be much higher
than the rest of the house).
SIs NOT in any part of the building where the tempera-
ture may exceed 150_F.
IMPORTANT
The electrical power source for the zone control sys-
tem, i.e. the transformer primary, and furnace or
blower coil unit must be the same source. In addi-
tion, the zone control system power−up must occur
at the same time or before the furnace or blower coil
unit is powered up.
Discharge Air Temperature Probe
CAUTION
This device is manufactured using unpainted and
prepainted metal. Sharp sheet metal edges can
cause injury. When installing the device, avoid acci-
dental contact with sharp edges.

Page 5
HARMONY IIITSERIES
Install the discharge air temperature probe in the dis-
charge plenum downstream from the cooling coil. Be sure
that the discharge air will pass over the sensor before the
air is distributed into the duct system. A typical upflow fur-
nace probe installation is shown in figure 4.
1/3 the
depth of the
plenum
Figure 4
Discharge Air Temperature Sensor Placement
(Typical Upflow Furnace)
sensor plenum
coil
furnace or
blower coil
10"
front
sensor
discharge plenum
(top view)
1/2 the width of the
plenum
sensor centered in discharge airflow
Fasten the probe bracket to the
plenum with two self- tapping
sheet metal screws.
PLENUM
Connect wires to DAS on Zone Control
Board (see figures 19 through 21)
Be sure that the tip of the sensor is located approximately
10 inches from the indoor coil in the discharge plenum, and
1/3 the depth of the plenum, and centered over the dis-
charge airflow, side-to-side.
Thermostats
Locate each thermostat in its zone. If two or more rooms
are within a single zone, place the thermostat in a location
that is central to all rooms. For example, if a zone contains
two bedrooms, try to place the thermostat in a hallway near
both bedrooms.
Do not install thermostats in drafty areas, behind doors or
in corners, near radiant heat sources such as appliances
and sunny windows, near concealed pipes and chimneys,
or in unconditioned spaces such as closets or exterior
walls.
Dampers
Motorized dampers in the supply duct system regulate air
to the zones.
IMPORTANT
Up to 5 dampers per zone may be connected in par-
allel to the zone control panel not to exceed a total
of six dampers for entire system.
Some applications will be unique and require more than
one damper per zone. If additional dampers are required,
refer to the the wiring diagram in the Common System
Component Wiring section (page 12). Also, if more than 6
dampers are used, another transformer and isolation relay
will be necessary.
For more effective zone isolation, the return duct system
may also be dampered by zone. Dampers for each zone
must be wired in parallel. Install dampers in the desired
locations; then run thermostat wire from the damper to the
zone control board and slave relays as needed.
Transformer
Obtain an appropriately-rated transformer and electrical
junction box (see table 1). Install the transformer in the
electrical junction box near the zone control board.
Pressure Switch (Heat Pump Systems Only)
NOTE − If a pressure switch is factory installed in the unit,
do not remove the switch or switch wires.
Use a saddle valve (3/8" or 1/2") to install the pressure
switch in the discharge line between the compressor and
the reversing valve. The switch may also be fastened di-
rectly to the suction valve service port which becomes the
high side in heat pump mode.

Page 6
505023M 04/06
Blower Control Adjustment
Variable-speed furnaces and blower coil units are
equipped with a variable-speed control board. The blower
motor speed must be adjusted to produce the zoning CFM
requirements managed by the zone control system.
The variable-speed motor (VSM) in the furnace is con-
trolled by the SureLight®furnace control board. The motor
in the variable-speed blower coil unit is controlled by the
BDC3 drive control. Adjustment of these drive controls is
by jumper setting selection and is described in the follow-
ing paragraphs.
Variable-Speed Furnace − Jumper Settings
Locate the SureLight®board in the furnace control box
area. Switch settings on this board control blower CFM.
Before connecting the zone control board to the Sur-
eLight®board, complete the applicable electrical adjust-
ments.
SureLight®Control Board Selections
Figure 5
JUMPER
W951
IMPORTANT:
CUT JUMPER
w914
®
be sure
jumper on
t’stat pins is
set on two"
JUMPER
W915
IMPORTANT! − Be sure to read the Electrical Adjustments
immediately following before cutting jumpers.
IMPORTANT
Be sure to cut jumper W914; if not cut, the zone con-
trol board DS fuse will blow.
WARNING
Electrical Shock Hazard! Disconnect
power from unit and wait at least five
minutes to allow capacitors to dis-
charge before attempting to adjust
motor speed tap settings.
1. Electrical Adjustments − SureLight®Board
DIn all cases, cut jumper W914 (between R & DS,
see figure 5); if not cut, the zone control board DS
fuse will blow.
DIF dual fuel − cut jumper W951 (between R & O).
DIF 2-stage outdoor unit, cut jumper W915 (be-
tween Y1 & Y2).
DIn all cases − be sure T’STAT jumper is on TWO".
DIn all cases − cut and tape wires 2 & 13 on the VSM
harness connecting SureLight®board to motor
(figure 6).
16
8
15 14 13 12 11 10 9
7654321
cut and tape
wire #13
(furnace
application only) CUT & TAPE WIRE #2
(LOOK FOR RAISED
NUMBERS ON BACK
OF PLUG)
Figure 6
SureLight®Board Cable Modifications
2. Set Upper CFM Limit
DDetermine the maximum system CFM require-
ments (sum of all the individual zones).
DFrom the Blower Motor Performance table (see
unit installation instructions) determine the HIGH
Speed cool dip switch setting that corresponds to
this CFM.
DSet the HIGH Speed cool dip switch setting on the
board to this value.
NOTE − The lower limit of blower CFM is factory set. It is
not field adjustable.

Page 7
HARMONY IIITSERIES
Variable-Speed Blower Unit − Jumper Settings
Locate the BDC3 board in the blower control box. Jumper
settings on the BDC3 board control the blower CFM.
Before connecting the zone control board to the BDC3
board, complete the following electrical adjustments.
Figure 7
Blower Coil Control Box
1
4
7
3
6
9
K20 INDOOR
BLOWER RELAY
JUMPER
DS − Y1
JUMPER
Y1 − Y2
JUMPER
R − W2
JUMPER
R − O
JP1
CUT
wire near the
BDC3 board
JP1 pin 2
then,
RE−ROUTE
to G terminal
1. Electrical Adjustments − BDC3 Board
DIF 2-stage outdoor unit − remove jumper Y1 − Y2
(see figure 7).
DIF heat pump − cut jumper R − O.
DIn all cases − remove jumper DS − Y1.
DIn all cases − the wire from K20 terminal 4 to
BDC3 board JP1 pin 2 must be re−routed to estab-
lish an electrical connection between K20 terminal
4 and terminal G, as shown in figure 7. Cut the wire
near JP1 pin 2. Using the wire still connected to
K20 terminal 4, strip the cut end and connect it to
terminal G. Tape the exposed end of the short JP1
pin 2 wire.
DIn all cases − remove any factory−installed jumper
between terminal R and W1, W2, or W3.
DIn all cases − cut and tape wire 7 (see figure 8) on
the VSM harness that runs from the BDC3 board
to the motor.
9
Figure 8
4
5
1
12
2
11
13
3
9
10
7
8
6
14
15
(LOOK FOR
RAISED NUMBERS
ON BACK OF
PLUG)
CUT & TAPE WIRE #7
BDC3 Board Cable Modifications
2. Set the upper limit of blower CFM as follows:
DDetermine the maximum system CFM require-
ments (sum of all the individual zones).
DFrom the Blower Motor Performance table in the
unit’s installation instructions, determine the
COOL Speed jumper setting that corresponds to
this CFM.
DSet the COOL Speed jumper setting on the BDC3
board to this value.
For more information on setting blower speed, refer to sec-
tion on Blower Speed and Adjustment" in the blower unit’s
installation instructions.
BDC3 Control Board Selections
JP1 15 PIN PLUG
(BOARD TO MOTOR)
1
2
3
4
1
2
3
4
1
2
3
4
TEST
−
+
NORM
ADJUST HEAT COOL DELAY CFM RUN
24V/1A
ACC
JP1
ACCESSORY RELAY CONTACTS (DRIVES
OPTIONAL ACCESSORY RELAY)
OPERATIONAL SELECTOR PINS
(Affects both heating and cooling modes)
DIAGNOSTIC
LEDS
FAN DELAY
SELECTOR PINS
MAXIMUM CFM SELEC-
TION (see note)
NOT USED
NOTE − Minimum
blower CFM is not
adjustable.
Figure 9

Page 8
505023M 04/06
Zone Control Board Jumper Settings
Setup is required to allow the zone control system to con-
trol equipment staging and deliver the proper amount of
CFM to the zones. Only qualified technicians should per-
form equipment setups.
The zone control board jumper banks (see figure 10) deter-
mine how the system is configured to function.
Figure 10
HEATING STAGING
JUMPERS
coolING STAGING
JUMPERS
continuous air reduction
JUMPERS
heating air reduction
JUMPERS
Zone Control Board Jumper Banks
PIAB
JUMPERS
CAUTION
Static electrical discharge will damage electronics.
Discharge static electricity before touching the zone
control board. Touch a grounded metal object be-
fore touching the circuit board.
Percent Into Adjustment Band (PIAB) Jumpers
The adjustment band is the difference between the mini-
mum and maximum CFM rating of the air handler. The
zone control system allows the technician to direct an ap-
propriate percentage of that air volume to each zone. Vol-
ume settings must be selected for zone 1 and at least one
other zone (see figure 11). Unused zones must have jump-
er(s) set on OFF. Jumper settings range from 0% to 100%.
Figure 11
Pin shown with
jumper on
ZONE 1 AT 10%.
Pin shown with
jumper on
ZONE 2 AT 0%
(allows min. cfm
airflow).
Typical Air Selection Jumper Pin Settings
ZONE 1 ZONE 3
PIAB PIAB
ZONE 2 ZONE 4
PIAB PIAB
NOTE − Only zones 2,
3, & 4 have an OFF
setting.
ZONES 3
AND 4 ARE
SHOWN
NOT USED
(JUMPERS
SET ON
OFF").
NOTE − If replacing a Harmony II®system, use table 3 to
maintain equivalent air settings when setting up the
Harmony IIItsystem.
Table 3
Air Jumper Positions Conversion Chart
Model Equivalent Positions (%)
Harmony II®25 35 45 55 65 75 85 95
Harmony IIIt0 10 30 40 50 70 80 90
When jumpers are set to 0%, this corresponds to the mini-
mum air volume available according to the air handler
installation instructions, not 0% of maximum air. This is
the Percentage Into Adjustment Band of the motor (PIAB).
For example, if an air handler has a minimum air volume of
800 CFM, and a maximum of 1500 CFM, and the jumper is
set to 0%, the air delivered will be 800 CFM. See figure 12.
Figure 12
PIAB = 0% Min. CFM PIAB = 100% Max. CFM
0 CFM
Motor runS AT MINIMUM BLOWER SPEED
Max. CFM
Air Delivery (CFM) Scale
ADJUSTMENT BANDFIXED BAND
Similarly, if the jumper is set to obtain 50%, the air handler
will deliver: 0.50*(1500−800) + 800 = 1150 CFM. That is:
zone jumper setting * (the CFM adjustment range of the
motor) + the minimum motor CFM = CFM delivered.
Determine Air Selection Jumper Settings
1. Use a cooling load analysis to determine the required
CFM for each zone.
2. Determine the minimum CFM for the indoor unit.
NOTE − APIAB Calculation Worksheet has been pro-
vided on Page 30. This will guide you through the cal-
culations and document the zone control system PIAB
settings. Complete this worksheet before going to the
job site to facilitate the installation process.
3. Using the formula in Table 4 and the worksheet at the
back of this manual, calculate the Percent Into Adjust-
ment Band (PIAB) using the values from steps 1 and
2 for each zone. This illustrates how to determine the
correct jumper for the PIAB for Zone 1, given the fol-
lowing assumptions:
DMaximum CFM 2220
(High cool jumper setting)
DMinimum CFM 720
DRequired CFM (zone 1) 1020
Table 4
Determine PIAB Jumper Settings Example
Formula:
PIAB = (Required CFM − minimum CFM)
(Maximum CFM − minimum CFM)
x 100
PIAB = (1020 − 720)
(2220 − 720)
x 100
PIAB = 300
1500 x 100
PIAB
==20%

Page 9
HARMONY IIITSERIES
4. Set the air selection jumper for the zone using the per-
cent air determined in step 3. If the percent air falls be-
tween available jumper settings, select the nearest
unit of ten.
5. For each zone, repeat steps 1 through 4.
Continuous Air Reduction Jumpers
During continuous fan mode with no heating or cooling de-
mand, the blower runs at the total percentage of the CFM
jumper settings of the zones calling for continuous fan,
which cannot exceed 100% of blower capacity. The contin-
uous air reduction feature enables the blower speed to be
reduced by a percentage of the blower speed during con-
tinuous fan mode.
The selections are 75%, 50%, 25% and 0%. The factory
places the jumper on 0%. Set the jumper to the position
equal to the amount of continuous air reduction desired.
See figure 13.
NOTE − The blower will not deliver less than it’s minimum
CFM even if the air reduction percentage is less.
CONTINUOUS HEATING
0%
20%
40%
75%
50%
0%
25%
Figure 13
Air Reduction Jumper Settings
factory
settings
shown
heating jumper
Must be set on 0%
for heat pump
application
Heating Air Reduction Jumpers
The heating air reduction jumper enables the blower
speed, during heating, to be reduced by a percentage of
the cooling blower speed.
The selections are 40%, 20% and 0%. Jumpers are set to
0% from the factory. Set the jumper to the position equal to
the amount of heating air reduction desired. See figure 13.
NOTE − For heat pump applications, ALWAYS set the
jumper on 0%. High head pressures may result if air is re-
duced during heating mode.
Determining Actual Air Delivered By Blower
The actual CFM delivered to each zone will be determined
by the zone control system settings, blower motor control
board settings, zone thermostat demand status [calling for
heating, cooling, continuous fan, or no demand (zone
damper closed)], and the air distribution system’s duct
size.
When the zone control system is set for a particular zone,
heating reduction jumper, and/or continuous air reduction
settings determine the total CFM available from the unit as
follows:
1. Determine Total Unit PIABUsing the formula in
Table 5, calculate the Total Percent into Adjustment
Band. This illustrates how far into the adjustment band
the motor runs when more than one zone is calling for
conditioning, given the following assumptions:
DZone 1 Jumper 30%
DZone 2 Jumper 10%
DZone 3 Jumper 20%
DZone 4 Jumper OFF
DZones calling 2 & 3
DMaximum CFM 2220
DMinimum CFM 720
Table 5
Total Percent Into Adjustment Band
Formula:
Total
PIAB
= (Sum of Calling Zones
Jumper Positions)
+ (# of Zones Calling − 1)
3
Total
PIAB
=(.10 + .20) +(2 − 1)
3
Total
PIAB
= .30 + .33
Total
PIAB
=63% (The motor will run 63% into the adjustment
band of the motor.)
2. Determine Total CFM DeliveredContinuing from
the previous example and assumptions, and using the
formula in Table 6, calculate the total CFM delivered.
Table 6
Determine Total CFM Delivered
Formula:
Total
CFM = (Total PIAB) X (Max CFM − Min CFM) + (Min.
CFM)
Total
CFM
=(.63) X (2220 − 720) + (720)
Total
CFM
= (.63) X (1500) + (720)
Total
CFM
= 1665
Again, the maximum and minimum CFM values used
in the formula should correspond to the jumper set-
tings on the blower control board. This value repre-
sents the volume of air received if all zones were call-
ing for cooling.

Page 10
505023M 04/06
3. Determine heating PIAB and total heating air CFM
delivered during a heating callCalculate these to-
tals using the formulas and example in Table 7. The ex-
ample uses the following assumptions:
DZone 1 Jumper 30%
DZone 2 Jumper 50%
DZone 3 Jumper 40%
DZone 4 Jumper OFF
DZones calling for heat 1 & 3
DHeat reduction jumper 20
DMaximum CFM 2220
DMinimum CFM 720
Table 7
Determine Total Heating CFM Delivered
Formulas:
Total PIAB =
(Sum of Calling Zones
Jumper Positions) +(# of Zones Calling − 1) 3
Heating PIAB =
Total PIAB x (1 − Heating air reduction setting)
Total Heating CFM =
Heating PIAB x (CFM Max − Min) + (Min CFM)
1st− Find Total PIAB:
[Jumpers 30% +0% +40% +0%] .30 +.00 +.40 +.00. . . . . .
+ [2 zones −1]/3 +. 33. . . . . . . . . . . . . . . . . . . .
TOTAL 1.03. . . . . . . . . . . . . . . . . . . . . . . . . . . .
Blower cannot support 103%; uses 100% = 1. . .
2nd− Find Heating PIAB: b
[Total PIAB] 1. . . . . . . . . . . . . . . . . . . . . . .
x [1−Heating air reduction setting] x 1−.2. . . . .
TOTAL = .8. . . . . . . . . . . . . . . . . . . . . . . . . . . .
3rd− Find Heating Total CFM: b
[Heating PIAB] .8. . . . . . . . . . . . . . . . . . . . .
x [CFM (Max) 2220 − (Min) 720] x 1500. . . . . . .
+ [Min CFM] + 720. . . . . . . . . . . . . . . . . . . . . . .
TOTAL = 1920 CFM. . . . . . . . . . . . . . . . . . . . . . . . . . . .
4. Determine total air delivered during a continuous
blower callCalculate these totals using the formu-
las and example (Table 8) which uses the same as-
sumptions as table 7, except with zones 1, 2 and 3 call-
ing for cooling, and with 25% air reduction:
Table 8
Determine Total Continuous CFM Delivered
Formulas:
Total PIAB =
(Sum of Calling Zones
Jumper Positions) +(# of Zones Calling − 1) 3
Continuous Air PIAB =
Total PIAB x (1 − Cont. air reduction setting)
Total Continuous CFM =
Cont. Air PIAB x (CFM Max −
Min) + (Min CFM)
1st− Find Total PIAB:
[Jumpers 30% +50% +40% +0%] .30 +.50 +.40 +.00. . . . .
+ [3 zones −1]/3 +. 66. . . . . . . . . . . . . . . . . . . .
TOTAL 1.86. . . . . . . . . . . . . . . . . . . . . . . . . . . .
Blower cannot support 186%; uses 100% = 1. . .
2nd− Find Continuous Air PIAB: b
[Total PIAB] 1. . . . . . . . . . . . . . . . . . . . . . .
x [1−Continuous air reduction setting] 1−.25. .
TOTAL = .75. . . . . . . . . . . . . . . . . . . . . . . . . . . .
3nd− Find Total Continuous CFM: b
[Continuous Air PIAB] .75. . . . . . . . . . . . . .
x [CFM (Max) 2220 − (Min) 720] x 1500. . . . . . .
+ [Min CFM] + 720. . . . . . . . . . . . . . . . . . . . . . .
TOTAL = 1845 CFM. . . . . . . . . . . . . . . . . . . . . . . . . . . .
IMPORTANT
If any changes are made to the blower speed selec-
tions on the SureLight®or BDC3 boards, the zone
control PIAB calculations must be performed again
to ensure proper airflow.

Page 11
HARMONY IIITSERIES
SYSTEM Configuration Jumper
The SYSTEM configuration jumpers must be inserted to
select the type of cooling and heating system that has
been installed.
For a furnace and 2−stage air conditioner combination, se-
lect the GAS and 2COOL positions as shown in on the left-
hand side of figure 14. In this configuration, the maximum
discharge temperature the furnace is allowed to run is
160°F (temperature range illustrated in figure 15). At that
temperature, the zone control system removes a heat de-
mand from the furnace for a minimum of 5 minutes and un-
til the temperature comes back within normal operating
temperatures. While at or above 160°F, the control unit sig-
nals for continuous blower operation to those zones from
which a thermostat heat demand is received. When setting
up the furnace control board options, be sure to set the
BLOWER-OFF DELAY to no greater than 210 SECONDS.
For a heat pump with electric backup heat, select the HP
position as shown in on the right-hand side of figure 14. In
this configuration, the maximum discharge temperature
the electric heat or heat pump is allowed to run is 135°F. At
that temperature, the zone control system removes de-
mand from the heating unit for a minimum of 5 minutes and
until the temperature returns to the normal operating tem-
perature range. While at or above 135°F, the control unit
signals for continuous blower operation to those zones
from which a thermostat heat demand is received.
Select the number of equipment cooling stages by placing
the COOL stages jumper to the appropriate side (1COOL
or 2COOL). Similarly, set the number of Heat Pump stages
(1HP or 2HP). Jumper settings on the right-hand side of
figure 14 illustrate the proper settings for a 2-stage heat
pump and two-stage air conditioning system.
SYSTEM Configuration Jumper
(Typical configuration shown; yours may differ)
Gas furnace & 2−stage AC
2-stage heat pump w/1-stage
aux. electric heat & 2−stage AC
SYSTEM E−HEAT SYSTEM E−HEAT
Configuration Stages Configuration Stages
HP GAS df hp gas df
2cool 1cool 1 2cool 1cool 1
2hp 1hp 2 2hp 1hp 2
33
DOESN’T MATTER
Dual fuel heating &
1−stage AC & heat pump
SYSTEM E−HEAT
Configuration Stages
HP GAS df gas /df
2cool 1cool 1 2cool 1cool 1
2hp 1hp 2 2hp 1hp 2
33
Figure 14
NOTE − Variations to the jumper configuration settings
shown in figure 14 are described in figure 18.
When using a heat pump with electric backup heat, insert
an E−HEAT jumper to select the total number of available
electric heat stages. Upper right-hand view in figure 14
shows 1 heat-strip configuration.
The lower left diagram in figure 14 shows a dual−fuel con-
figuration (heat pump for heat and cool with gas backup
heat). The E−Heat stages jumper must be set to DF for dual
fuel operation.
Heating Staging Temperature Jumper
The Heating Staging Temperature jumper is used to set the
discharge air temperature at which the equipment will turn
second stage on. It is selectable between 85 and 130°F
with a built in differential of 20°F.
During operation, whenthe dischargeair temperaturefalls
below the setpoint, second stage operation begins. If the
discharge air temperature reaches the setpoint plus 20°F,
second stage operationwill ceaseandfirst stageoperation
will resume until the temperature again falls below the set
point.
The recommended settings for heating staging and maxi-
mum discharge temperatures are as follows (illustrated in
figure 15):
SHeat Pumps (system configuration jumper: HP; heat-
ing staging jumper: 90°F (range: 85− 110°F). The max-
imum discharge air temperature at which the heat
pump/electric heat is allowed to run is fixed at 135°F.
SGas Furnaces (system configuration jumper: GAS;
heating staging jumper: 120°F (range: 100 − 130°F).
The maximum discharge air temperature at which the
furnace is allowed to run is fixed at 160°F.
Heating Maximum and Minimum Settings
Jumper Setting = 90°F
(Heat Pump Settings 85°F−110°F)
Jumper Setting = 120°F
(Furnace Settings 100°F−130°F)
blower only
low fire
either speed
high fire
Settings can be from 85°F to
130°F with 20°F differential
135°F
110°F
160°F
140°F
120°F90°F
total
differential =
20°F
total
differential =
20°F
INCREASING TEMPERATURE
Figure 15
When the zone control system is applied to a heat pump
with electric heat, the electric heat will be staged on to
maintain the discharge air temperature set by the heating
stage jumper position.

Page 12
505023M 04/06
Cooling Staging Temperature Jumper
The Cooling Staging Temperature jumper bank is used to
set the discharge air temperature at which the unit will turn
on second stage. It is selectable between 50°, 55° and
60°F. There is a 7 degree total differential associated with
this staging temperature. The differential starts at the set-
point, and extends to 7 degrees above the setpoint.
For example, with the setting at 50°F, and the unit running
in first stage with a discharge temperature of 55 degrees,
the unit will continue to run at first stage. Should the dis-
charge temperature rise due to increased zones calling,
the temperature would have to reach 57°F before the unit
would start running at second stage.
Cooling Maximum and Minimum Settings
Jumper Setting = 50°F Jumper Setting = 60°F
Settings can be from 50°F to
60°F with 7°F differential
high speed
either speed
low speed
blower only
45°F
57°F
45°F
67°F
60°F50°F
total
differential =
7ºF
total
differential =
7°F
INCREASING TEMPERATURE
Figure 16
The discharge air would then have to reach below 50°F be-
fore the unit would stage down to first stage again. This will
prevent any rapid staging of the equipment. See figure16.
Common System Component Wiring
Use thermostat wire to connect dampers, damper trans-
formers, and the DAS probe with the zone control system.
IMPORTANT
Avoid running any control wiring close to AC house
wiring. If this cannot be avoided, limit close parallel
of power and control wiring to a few feet.
Dampers and Damper Transformer Wiring
Connect dampers to the zone control board as shown in
figure 17. A total of six dampers may be connected at the
damper output terminals on the zone control board. If addi-
tional dampers are used, additional transformers and re-
lays will be needed.
Fuse F1 will protect the damper outputs from a short circuit
or overload in the damper wiring.
If dampers are applied to the return duct system, the
dampers for each zone must be wired in parallel. Connect
damper transformer to zone control board terminal block.
Refer to the Extended Damper Wiring section in figure 17
for wiring connections.
Discharge Air Sensor (DAS) Probe Wiring
Wire discharge air sensor probe to zone control board. The
variable immersion-temperature probe is not polarity sen-
sitive.
Figure 17
120
VAC
24
VAC
EXTENDED
DAMPER
TRANSFORMER
(NOT TO EXCEED
75 VA) CLASS II
WIRING
120 VAC
24 VAC
ZONE
RELAY 4
ZONE
RELAY 3
ZONE
RELAY 2
ZONE
RELAY 1
ZONE 1
DAMPER
ZONE 2
DAMPER
ZONE 3
DAMPER
ZONE 4
DAMPER
EXTENDED
ZONE 1
DAMPER
EXTENDED
ZONE 2
DAMPER
EXTENDED
ZONE 3
DAMPER
EXTENDED
ZONE 4
DAMPER
Transformer rating should be sized to
adequately handle zone dampers
(1−4) plus relays (K1−K4) not to
exceed class II wiring limit of 75 VA.
Combined load of zone dampers and
zone relays not to exceed 60VA.
Use Lennox Part 69J56 for Zone
Relays 1 through 4.
EXTENDED
DAMPER
WIRING
Damper and Extended Damper Wiring Diagram ZONE CONTROL,
THERMOSTATS,
& DAMPERS
TRANSFORMER

Page 13
HARMONY IIITSERIES
Component Specific Wiring
Thermostat Wiring
Using standard electronic 1-heat /1-cool non-heat pump,
non-power robbing thermostats, and five−wire thermostat
cable, wire units as follows:
1. Wire each thermostat to terminals Y, W, G, R, and C.
2. Run cable from each of the thermostats to the zone
control board. Mark each cable according to the zone
thermostat from where it originates.
3. Strip the cables and attach each of the 5 wires to the
zone control board (see figures 19, 20, 21).
Gas Furnace Wiring
After the furnace is installed, field wire the unit as de-
scribed in the installation instructions provided with the fur-
nace. Use thermostat wire to connect the furnace and the
zone control board and to connect the zone control panel
24V C" to SureLight®board terminal strip C" (see wiring
diagram in figure 19).
IMPORTANT
The common C" terminal of the Harmony IIItzone
control board MUST be connected to the common
terminal of the SureLight®furnace board, or if using
a blower coil, MUST be connected to the common
terminal of the blower coil terminal strip.
Condensing Unit Wiring
After the condensing unit is installed, field wire the unit as
shown in the installation instructions provided with the unit.
Use thermostat wire to connect the condensing unit to the
zone control board (see figure 19).
Pressure Switch Wiring
Pull a two−wire thermostat cable from the field-installed
pressure switch to the zone control board and connect at
the pressure switch, and at the zone control board as
shown in the connection location diagram (see figure 20).
Blower Coil Wiring
After the blower coil unit is installed, field wire the unit as
shown in the installation instructions provided with the unit.
Use thermostat wire to connect the blower coil to the zone
control board (see figure 20) and to connect wire from zone
control panel 24V C" to blower coil terminal strip C".
NOTE − If not already done, remove the wire to K20 blower
relay terminal 7 (on BDC3 board) and tape it off. Also, be
sure the factory−installed jumper between terminal R and
W1, W2, and W3 has been removed.
Heat Pump Unit Wiring
After the heat pump unit is installed, field wire the unit as
shown in the installation instructions provided with the unit.
Use thermostat wire to connect the heat pump to the zone
control board (see figure 21).
Variations on Common Applications
Several variations may be required for specific applica-
tions. Figure 18 shows alternate wiring and describes spe-
cific jumper configurations and other special modifications
required for each variation.
Aside from the variations described in figure 18, the con-
nectivity is the same as shown in figure 19. Note that there
will be no Pressure Switch nor Balance Point Sensor in any
of these variations.
Figure 18
COOLING ONLY
JUMPERS: System configuration−
GAS; 1COOL or 2COOL;
Others do not matter.
BDC3 Board: As applicable, cut
jumpers and harness wires (see
Electrical Adjustments − BDC3
Board on page 7).
HOT WATER COIL (CBWMV)
JUMPERS: System configuration−
GAS; 1COOL or 2COOL;
Others do not matter.
BDC3 Board: As applicable, cut
jumpers and harness wires (see
Electrical Adjustments − BDC3
Board on page 7).
COOLING WITH ELECTRIC HEAT
JUMPERS: System configuration−HP;
1COOL or 2COOL.
E−Heat stage jumper set on # agreeing
with # of available heat stages.
E−HEAT Selector Switch always ON.
BDC3 Board: As applicable, cut jumpers
and harness wires (see Electrical Adjust-
ments − BDC3 Board on page 7).
For any option or variation, connect thermostat wire between C" on terminal strip(s) of controlled equipment and zone control board 24VAC C"
terminal.
Harmony IIItZone Control System − Variations on Common Applications
Y1
Y2
C
R
R
G
W1
W2
C
DS
Y1
Y2
O
RC
W1−Def
RH
G
W1
W2
W3
DS
Equipment
Equipment
CONDENSING
UNIT
Y1
Y2
C
R
R
G
W1
W2
W3
C
DS
Y1
Y2
O
RC
W1−Def
RH
G
W1
W2
W3
DS
Equipment
Equipment
CONDENSING UNIT
ELECTRIC HEAT CBWMV
Y1
Y2
C
R
R
G
W1
W2
C
DS
Y1
Y2
O
RC
W1−Def
RH
G
W1
W2
W3
DS
Equipment
Equipment
CONDENSING
UNIT
VSM BLOWER COIL

Page 14
505023M 04/06
BPS BPSPS PS
DAMPERS(Spring
open, power close)
85
90
100
110
120
130
0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%
NotUsed
OFF
0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%
Zone4
PIAB
Zone1
PIAB
Zone2
PIAB
Zone3
PIAB
SYSTEM
Configuration
E−HEAT
Stages
Heating
Staging Temp
50
55
60
Cooling
Staging Temp
0%
20%
40%
0%
25%
50%
75%
OFF
0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%
OFF
0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%
Cont. Air
Reduction
Heating Air ‘
Reduction
DF
1
2
3
HP
2COOL
2HP
GAS
1COOL
1HP
TDO
Fault
Recall
1/2 AMP
DS FUSE
SPARE DS FUSE
3 AMP
PANEL FUSE
SPARE PANEL FUSE
Thermostat 4 Thermostat 3
W C Y G R W C Y G R
Balance Point Sensor
Pressure Switch
Diag4 Diag3 Diag2 Diag1
E−Heat Vacation
damper 4 damper 3 Damper 2 Damper 1 Mode Mode Fan Cooling ElectHeating Heating Status
ESD CAUTION
TOUCH A GROUNDED METAL
OBJECT BEFORE TOUCHING
THE CIRCUIT BOARD
Harmony IIIt
V3.0 2004
System Configuration & E−Heat jumper
settings − page 11.
piab jumper settings −
page 8.
air reduction jumper
settings − page 9.
heat/cool staging
jumper settings − page
11.
120
VAC
24
VAC
C R
IMPORTANT! Connectivity is NOT COMPLETE until all electrical adjustments (jumpers and wiring changes) have been made.
See Electrical Adjustments for SureLight®Board (page 6) and for BDC3 Board (page 7).
Harmony IIItZone Control System Option 1 − Lennox Variable-Speed Gas Furnace &
Lennox 2-Stage Air Conditioner
Figure 19
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).
IMPORTANT
Connect
thermostat-gauge
wire to SureLight®
board C" terminal
(or to C" on blower
coil terminal strip)
Damper1
NC
NO
C
das
Damper2
NC
NO
C
Damper3
NC
NO
C
Damper4
NC
NO
C
Thermostat 2 Thermostat 1
W C Y G R W C Y G R
W C Y G R W C Y G R
DISCHARGE AIR SENSOR
88K38 (included)
OFF
Vacation
Mode
Selector
ON
OFF
E−Heat
Selector
ON
NOTE − Do not wire Y" wire(s) from the
Harmony IIItzone control board to the fur-
nace terminal strip. Doing so causes the
motor to search" for proper CFM.
Y1
Y2
C
R
R
G
W1
W2
C
DS
Y1
Y2
O
RC
W1−Def
RH
G
W1
W2
W3
DS
Equipment
Equipment VARIABLE SPEED
FURNACE
2-STAGE CON-
DENSING UNIT

Page 15
HARMONY IIITSERIES
Y1
Y2
O
RC
W1−Def
R
C
Y1
Y2
O
W1
R
G
W1
W2
C
DS
Harmony IIItZone Control System Option 2 − Lennox Heat Pump &
Lennox Variable-Speed Coil Blower
Figure 20
DAMPERS(Spring
open, power close)
DISCHARGE AIR SENSOR
88K38 (included)
85
90
100
110
120
130
0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%
NotUsed
OFF
0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%
Zone4
PIAB
Zone1
PIAB
Zone2
PIAB
Zone3
PIAB
SYSTEM
Configuration
E−HEAT
Stages
Heating
Staging Temp
50
55
60
Cooling
Staging Temp
0%
20%
40%
0%
25%
50%
75%
OFF
0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%
OFF
0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%
Cont. Air
Reduction
Heating Air ‘
Reduction
DF
1
2
3
HP
2COOL
2HP
GAS
1COOL
1HP
TDO
Fault
Recall
1/2 AMP
DS FUSE
SPARE DS FUSE
3 AMP
PANEL FUSE
SPARE PANEL FUSE
Thermostat 4 Thermostat 3
Thermostat 2 Thermostat 1
W C Y G R W C Y G R
W C Y G R W C Y G R
BPS BPSPS PS
Balance Point Sensor
Pressure Switch
Diag4 Diag3 Diag2 Diag1
E−Heat Vacation
damper 4 damper 3 Damper 2 Damper 1 Mode Mode Fan Cooling ElectHeating Heating Status
ESD CAUTION
TOUCH A GROUNDED METAL
OBJECT BEFORE TOUCHING
THE CIRCUIT BOARD
LENNOX
Harmony IIIt
V3.0 2004
System Configuration & E−Heat jumper
settings − page 11.
piab jumper settings −
page 8.
air reduction jumper
settings − page 9.
heat/cool staging
jumper settings − page
11.
120
VAC
24
VAC
C R
PRESSURE SWITCH
21J18 (R−22)
51M08 (R−410A
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).
RH
G
W1
W2
W3
DS
Equipment
Equipment
W C Y G R W C Y G R
Damper1
NC
NO
C
das
Damper2
NC
NO
C
Damper3
NC
NO
C
Damper4
NC
NO
C
IMPORTANT
Connect
thermostat-gauge
wire to C" terminal
on Heat Pump
terminal strip
VARIABLE SPEED
BLOWER COIL
HEAT PUMP
OFF
Vacation
Mode
Selector
ON
OFF
E−Heat
Selector
ON
IMPORTANT! Connectivity is NOT COMPLETE until all electrical adjustments (jumpers and wiring changes) have been made.
See Electrical Adjustments for SureLight®Board (page 6) and for BDC3 Board (page 7).
NOTE − Do not wire Y" wire(s) from the
Harmony IIItzone control board to the coil
blower unit terminal strip. Doing so causes
the motor to search" for proper CFM.

Page 16
505023M 04/06
BPS BPSPS PS
Harmony IIItZone Control System Option 3 − Lennox Heat Pump &
Lennox Variable-Speed Gas Furnace (Dual Fuel)
IMPORTANT! Connectivity is NOT COMPLETE until all electrical adjustments (jumpers and wiring changes) have been made.
See Electrical Adjustments for SureLight®Board (page 6) and for BDC3 Board (page 7).
BALANCE POINT
SENSOR 56A83
DAMPERS(Spring
open, power close)
85
90
100
110
120
130
0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%
NotUsed
OFF
0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%
Zone4
PIAB
Zone1
PIAB
Zone2
PIAB
Zone3
PIAB
SYSTEM
Configuration
E−HEAT
Stages
Heating
Staging Temp
50
55
60
Cooling
Staging Temp
0%
20%
40%
0%
25%
50%
75%
OFF
0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%
OFF
0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%
Cont. Air
Reduction
Heating Air ‘
Reduction
DF
1
2
3
HP
2COOL
2HP
GAS
1COOL
1HP
TDO
Fault
Recall
OFF
Vacation
Mode
Selector
ON
OFF
E−Heat
Selector
ON
1/2 AMP
DS FUSE
SPARE DS FUSE
3 AMP
PANEL FUSE
SPARE PANEL FUSE
Thermostat 4 Thermostat 3
W C Y G R W C Y G R
Balance Point Sensor
Pressure Switch
Diag4 Diag3 Diag2 Diag1
E−Heat Vacation
damper 4 damper 3 Damper 2 Damper 1 Mode Mode Fan Cooling ElectHeating Heating Status
PRESSURE SWITCH
21J18 (R−22)
51M08 (R−410A)
ESD CAUTION
TOUCH A GROUNDED METAL
OBJECT BEFORE TOUCHING
THE CIRCUIT BOARD
LENNOX
Harmony IIIt
V3.0 2004
System Configuration & E−Heat
jumper settings − page 11.
PIAB jumper
settings − page 8.
Air reduction jumper
settings − page 9.
Heat/cool staging jumper
settings − page 11.
1 2 3
120
VAC
24
VAC
C R
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).
Damper1
NC
NO
C
das
Damper2
NC
NO
C
Damper3
NC
NO
C
Damper4
NC
NO
C
Thermostat 2 Thermostat 1
W C Y G R
W C Y G R
W C Y G R
W C Y G R
Y1
Y2
O
RC
W1−Def
R
C
Y1
Y2
O
W1
R
G
W1
W2
C
DS
RH
G
W1
W2
W3
DS
Equipment
Equipment
DISCHARGE AIR SENSOR
88K38 (included)
IMPORTANT
Connect
thermostat-gauge
wire to SureLight®
board C" terminal
HEAT PUMP
VARIABLE
SPEED
FURNACE
Figure 21
NOTE − Do not wire Y" wire(s) from the
Harmony IIItzone control board to the
furnace terminal strip. Doing so causes
the motor to search" for proper CFM.
System Operation
This section describes the operation of the zone control
system.
Zone Thermostats
Only electronic thermostats with a C" terminal may be
used with the zone control system. The zone control sys-
tem distinguishes between heat pump and heat/cool ap-
plications via the SYSTEM jumper placement on the zone
control board.
1. Cool / Heat / Auto−Changeover ModesZone thermo-
stats send a heating or cooling signal to the zone con-
trol board. Thermostat servicing zone 1 is the central
control thermostat. Zones 2, 3 and 4 each have their
own thermostat. Thermostats may be standard or au-
tochangeover type.
Heat and cool demands present at the same time from
different zones (opposing demands) are satisfied on a
first come first served basis. If a heating demand and a
cooling demand reach the zone control board at the
same time, the heating demand is satisfied first. If op-
posing demands persist, the system will work to satis-
fy the current demand for a maximum of 20 minutes,
then switch over and try to satisfy the opposing de-
mand for a maximum of 20 minutes. When either de-
mand is satisfied, the system works to satisfy the other
demand.
NOTE − Allowing opposing demands to persist may
consume excess energy. If this condition continues,
check the installation (i.e. zone arrangement, supply
registers, return registers, zone loads etc.) and make
adjustments as necessary. Table 9 shows the time de-
lays that may be expected when opposing demands
are received from the zone thermostats.
The zone control system acknowledges a new or op-
posing demand as soon as it is received by illuminating
that zone’s thermostat input lights. If the first demand
is not satisfied by the time the delays elapse, the sys-
tem switches over and begins satisfying the opposing
demand. During the switchover, a delay may be im-
posed before the system begins satisfying the new de-
mand.

Page 17
HARMONY IIITSERIES
2. Fan On / Auto ModeZone thermostats can send a
continuous fan signal to the zone control system. The
zone control system will signal the blower to supply air
to zones calling for continuous fan while no other con-
ditioning calls exist. When the zone control system re-
ceives a conditioning call while satisfying a demand for
continuous fan, it signals the damper controlling the
continuous-fan zone to close. After the conditioning
demand is satisfied, the continuous-fan zone damper
is signaled to reopen.
3. Service Light (Heat pump only)The service light in
the central control thermostat is connected to the out-
door unit. The light illuminates when the outdoor com-
pressor needs to be serviced. The service lights in the
remaining zone thermostats are not connected.
4. Emergency Heat (Heat pump only)The emergency
heat switch prevents the outdoor compressor unit from
responding to a thermostat heating demand. The in-
door unit (furnace or strip heat) supplies all of the heat.
The emergency heat switch light illuminates when the
switch is engaged, and the auxiliary source is used to
satisfy the heating demand in all zones.
Balance Point Setting
(Dual Fuel Systems) Balance Point Sensor (56A83) com-
municates with the Zone Control Board whether or not to
force the Gas Furnace to satisfy heating demands, based
on a comparison of the Balance Point setting with the out-
door temperature.
Zone Mode
The zone control mode (Vacation switch OFF) utilizes the
zone control system’s full potential. While in this mode, the
zone control system will respond to demands from any
zone, controlling dampers and regulating blower CFM to
maintain comfort. When the system is in zone mode, the
zone control system responds to demands from any zone
thermostat. (Switch settings are shown in figures 19
through 21.)
The only OPEN supply-air dampers are those zones from
which a demand was received; all other dampers are
CLOSED. The blower operates at a speed based on the
position of the Zone PIAB selection jumpers (and the heat-
ing air reduction jumper, if a call for heat is present).
NOTE − To ensure that the zone control performs optimally,
avoid mixing air between the zones.
Central (Vacation) Mode
When in central mode (Vacation switch ON), the system
responds only to heating or cooling demands from the
master (Zone 1) thermostat); all zones will receive condi-
tioned air. All dampers remain open and the blower oper-
ates at full speed (minus the amount selected by the heat-
ing air reduction jumper). (Switch settings are shown in
figures 19 through 21.)
In Fan−Auto mode, the blower will cycle on and off with
each demand. During gas or electric-strip heating, the
blower may continue after the end of a demand until the
heater is cooled sufficiently.
Cooling Operation
When the Harmony IIItzone control system receives a
thermostat cooling call, the following events occurs:
SThe zone control unit checks to make sure it has been
at least 5 minutes since the last cooling call ended to
prevent starting against high head pressures.
SWhen timed−off delay is satisfied, the zone control unit
starts the outdoor unit with first−stage compressor and
slowly increases the indoor blower speed to achieve
proper CFM. Four minutes must elapse at this state to
allow the system to reach steady−state operation be-
fore staging again.
SThe zone control unit checks the discharge air sensor
for proper temperature. If measured temperature is
7ºF or more above the cooling staging jumper setting,
then Y2 energizes (if available). If both stages of cool-
ing are energized and 4 minutes has elapsed since the
last staging event, and the discharge air sensor (DAS)
detects a temperature less than the cooling staging
jumper, then Y2 is staged off.
SIf, at any time, the discharge air sensor measures a
temperature of 45ºF or below, the zone control unit de−
energizes the Y1 and/or Y2 output, stopping the com-
pressor and preventing the indoor coil from freezing
up. The compressor will not be energized again until
the temperature at the DAS rises by 10ºF and the
timed−off delay expires. During this time, continuous
fan is supplied to the zones calling for cooling.
Heating Operation
Gas furnaceIn this system, when the zone control re-
ceives a thermostat heating demand, the following events
occurs:
SThe zone control unit sends a W1 signal to the furnace,
which goes through its normal ignition sequence, ex-
cept that while the temperature at the DAS is below
100ºF, the zone control instructs the blower to run at
minimum speed.
SAfter the temperature at the DAS rises above 100ºF,
the zone control unit slowly increases the CFM deliv-
ered until it reaches the correct setting. During a call
for heat, the zone control stages the furnace up and
down to maintain the discharge air temperature be-
tween the heating staging jumper setting and 20ºF
above this jumper setting. There is a minimum 3 min-
ute delay between staging events.
Heat Pump with Electric HeatIn this system, when the
zone control receives a thermostat heating call, the follow-
ing events occurs:
SThe zone control unit starts the heat pump on first
stage.
SIf after 4 minutes, the temperature at the DAS is not
within the proper range (heating staging jumper setting
and heating staging jumper setting +20) the unit
stages up or down, accordingly.
SIf the air temperature cannot be maintained using the
heat pump alone, the zone control starts the electric
heating stages. Should the discharge temperature ex-
ceed 135ºF, the compressor (and any electric heat that

Page 18
505023M 04/06
may be on) is turned off and continuous fan runs (if the
demand for heat remains) until the air temperature
falls below 130ºF and the minimum timed−off delay ex-
pires.
SIf the heat pump goes into defrost mode, the zone con-
trol energizes all stages of compressor and the first
stage of electric heat. If the defrost process lasts lon-
ger than 20 minutes, the zone control, presuming a de-
frost board failure, de−energizes the heat pump and
instructs electric heat to service the remainder of the
current heating call. (The heat pump will be tried again
on the next heating call.)
Dual Fuel−Heat Pump with Gas FurnaceIn this sys-
tem, when it receives a thermostat heating call, the zone
control responds in one of two ways:
1. Outdoor temperature below balance point (bal-
ance point sensor closed): the zone control unit sends
a W1 signal to the furnace to satisfy heat demands,
staging the furnace to maintain discharge air tempera-
tures between 110ºF and 130ºF.
2. Outdoor temperature above balance point (bal-
ance point sensor open): the heat pump is first used
to satisfy the demand. If, after 20 minutes, the heat
pump fails to maintain the required discharge air tem-
perature, the zone control will discontinue using the
heat pump and initiates furnace heating. (A five−min-
ute delay exists between stopping the heat pump and
starting the furnace.) In this mode, all heating calls for
the next three hours are serviced with the gas furnace.
Also, diagnostic lights 2, 3, and 4 blink to indicate that
the board is operating within this 3−hour furnace lock−in
time. During this time, the zone control stages the fur-
nace to maintain discharge air temperatures between
110ºF and 130ºF. After the 3−hour delay expires, the
heat pump will again be tried on the next heating call.
Emergency heat mode
When the unit is setup for heat pump and the emergency
heat switch is turned on, the unit will satisfy all heating de-
mands with electric backup heat or, in a dual mode system,
the heat demand is satisfied by the gas furnace.
Operation & Troubleshooting Indicators
Zone Control Board LEDs
The zone control system operation is indicated by light
emitting diodes (LEDs) located on the zone control board.
In addition to operating condition, the LEDs provide valu-
able information system troubleshooting. The LEDs
(shown in figure 22) are thermostat, diagnostic, and output
status.
1. Thermostat LEDslocated along the upper edge of
the zone control board board. Each zone has three
LEDs to indicate a call for heating or cooling: green (in-
dicates a Y / compressor demand), red (indicates a W
/ heating demand) and amber (indicates a G / indoor
blower demand). These LEDs are labeled according
to the zone and demand.
System Indicators/Troubleshooting Devices
Figure 22
THERMOSTAT
LEDs
OUTPUT STATUS LEDs
DIAGNOSTIC
LEDs
TIME DELAY
OVERRIDE
FAULT
RECALL
EQUIPMENT
OUTPUT LEDs
2. Diagnostic LEDsDiags 1, 2, 3, 4located near the
bottom center of the the zone control board board.
These LEDs aid the technician in troubleshooting
problems. When an error is detected, LEDs illuminate
in a pattern. See Fault Recall and Time Delay Override
on page18.
3. Output LEDslocated along the bottom of the zone
control board and near connection terminals. These
red LEDs indicate the output status of dampers, fur-
nace, outdoor unit, etc. When an output is powered or
active, the corresponding LED is illuminated.
The LEDs are labeled according to output and func-
tion. For example, if Damper 1 LED is illuminated, it’s
damper has been signaled to close; when the LED is
extinguished, it’s damper has been signaled to open,
allowing air flow to that zone.
Fault Recall & Time Delay Override
When the Time Delay Override is pressed and held, the in-
ternal clock speeds up by a factor of 60. This overrides the
current time delay and permits the next event to occur.
Table 9 identifies the time delays used by the system.
When the Fault Recall button is pressed and released
(clicked), the fault codes are displayed (10 most recent).
When the fault recall button is pressed and held, the fault
codes are erased. Each code will be displayed for 10 sec-

Page 19
HARMONY IIITSERIES
onds starting with the most recent code, then the next most
recent, and so on. Pressing the button while recalling fault
codes will bypass the 10-second timer and go right to the
next fault code.
Use the Fault Recall button to observe diagnostic codes
that will indicate either correct operation, or help checkout
and troubleshoot problems in the zone control system.
Table 10 in the troubleshooting section (see page 25) iden-
tifies all diagnostic codes.
Press the button once while the system is operating. The
system will respond by momentarily lighting all four DIAG
LEDs then displaying the error code, if an error code is
stored in memory. This allows a visual check to verify that
all four LEDs are operational before displaying an error
code.
Time Delays
Timers used in the Harmony IIItsystem define delays
which precede or follow a demand, depending on the type
of function. The delays are used to control equipment con-
nected to the system. Table 9 shows how the most notice-
able delays are used.
New System Start−Up & Checkout
Powering the System (All Systems)
Adjust all thermostat settings so that no demand will occur.
Apply power to the furnace and to the zone panel trans-
former and observe the following: all four diagnostic LEDs
will light; then each individual diagnostic LED will light in
sequence; then all four diagnostic LEDs will light and extin-
guish. Finally, the status light will begin to flash, indicating
proper operation. Perform the gas and heat pump heating
checks on pages 20 through 24.
Table 9
Time Delays
Delay Time Function
Blower Off Delay (gas heat only) 3-1/2 min. Gas Furnace only. Dumps air into last zone called during cool down following heat demand.
Compressor Speed Change 4 min. Between low speed and high speed in order to make sure steady state is reached before stag-
ing.
Compressor Off Time 5 min. At end of demand. Equalizes pressure in refrigerant system and prevents short cycling.
Heat Staging (electric) 2 min. Between staging up or down (May stage faster to prevent overshoot/undershoot).
Heat Staging (gas) 3 min. Between staging up or down to achieve steady state.
Dual Fuel Furnace Lock-in Timer 3 hrs. Starts when system enters dual fuel furnace heating when the outdoor temperature is above
balance point. When operating within this 3-hour time, only the furnace is used for heating. Heat
pump will be tried again on the next call after this timer expires. Diagnostic LEDs 2, 3, and 4 will
flash when this timer is active.
Damper Hold 3-1/2 min. This timer is defined as the amount of time to hold the last zone calling open past the thermostat
call drop out. During this time, the panel will not energize the blower (except when a continuous
fan call exists); the controlled equipment will provide this signal. This is a non−adjustable timer
set at 210 seconds.
Autochangeover 20 min. When opposing demands are present, zone control system must work to satisfy current demand
at least 20 min. If current demand is not satisfied after time has elapsed, system will changeover
and satisfy opposing demand. On and Off delays above will also apply.

Page 20
505023M 04/06
Gas Heating Checkout − Single Zone
Prerequisites:
SZone 1 thermostat set to Heat
OUTPUT STATUS LEDs
DAMPER 2,3,4 on DAMPER 1 Off
W1 on
(W) RED on
hEATING onfan on
1. Set zone 1 thermostat for a heat demand; check:
DZone 1 thermostat W LED on (heating demand).
DDamper 1 LED off (damper open).
DDamper 2, 3, and 4 LEDs on (dampers closed).
DOutput Heat W1 LED on (furnace on).
DHeating LED on.
The furnace begins ignition sequence after zone 1 has
demanded heat. The zone control system will start the
furnace blower on low speed (0 PIAB) 45 seconds af-
ter the combustion cycle has begun.
2. When warm air is sensed by the discharge air sensor,
the fan LED will light and the blower will slowly in-
crease to speed required by the zone calling. The
blower operates at speed setting of PIAB jumper for
zone 1 and the jumper for heating air reduction. It may
require 60 − 90 seconds to reach this speed.
3. Set zone 1 thermostat for NO heat demand; check:
DZone 1 thermostat W LED off (no heat demand).
DOutput Heat W1 LED off.
DFan LED off.
DHeating LED off.
DDamper LEDs 2−4 remain on until after 3-1/2 min-
ute purge; then off.
To check the amount of air being delivered to each
zone and to confirm that each individual zone damper
functions properly, repeat these steps for zones 2 − 4.
Gas Heating Checkout − Multiple Zone
Prerequisites:
SAll zone thermostats set to Heat
OUTPUT STATUS LEDs
DAMPER 2,3,4 OFF
W1 on
(W) RED on
hEATING onfan on
1. Set all zone thermostats for a heat demand; check for
the following:
DAll zone thermostat W LEDs on (heat demands).
DLEDs dampers 1 − 4 off (all dampers open).
DOutput Heat W1 LED on (furnace on).
DHeating LED on.
The furnace begins ignition sequence after a heat de-
mand is detected. The zone control system will start
the furnace blower on low speed (0 PIAB) 45 seconds
after the combustion cycle has begun.
2. When warm air is sensed by the discharge air sensor,
the fan LED comes on and the blower will slowly in-
crease to speed required by the zones calling. The
blower operates at a speed equivalent to the sum of all
zone PIAB jumpers but at a maximum not to exceed
the setting of the heating air reduction jumper. It may
take the blower 60 to 90 seconds to reach this speed.
3. Set all zone thermostats for NO heat demands; check:
DOutput Heat W1 LED off.
DHeating LED off.
DFan LED off (blower turns off after delay).
DAll zone thermostat W LEDs off.
DDamperLEDs − Last zone thermostat demand re-
moved: LED is off (this zone’s damper remains
open during 3−1/2 minutepurge); other zones
damper LEDs are on during the 3−1/2 minute
purge (dampers closed). After 3−1/2 minute delay,
all dampers LEDs go off (dampers open).