Lennox Harmony III Installation Instructions Manual page 11

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
SYSTEM E−HEAT
Configuration Stages
HP GAS
2cool 1cool
2hp 1hp
DOESN'T MATTER
Dual fuel heating &
1−stage AC & heat pump
SYSTEM E−HEAT
Configuration Stages
HP GAS
2cool 1cool
2hp 1hp
Figure 14
NOTE − Variations to the jumper configuration settings
shown in figure 14 are described in figure 18.
2-stage heat pump w/1-stage
aux. electric heat & 2−stage AC
SYSTEM E−HEAT
Configuration Stages
df hp gas df
1 2cool 1cool 1
2 2hp 1hp 2
3 3
df gas /df
1 2cool 1cool 1
2 2hp 1hp 2
3 3
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, when the discharge air temperature falls
below the setpoint, second stage operation begins. If the
discharge air temperature reaches the setpoint plus 20°F,
second stage operation will cease and first stage operation
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):
S
Heat 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.
S
Gas 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)
total
differential =
20°F
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 11
Jumper Setting = 120°F
(Furnace Settings 100°F−130°F)
blower only
135°F 160°F
low fire
110°F 140°F
either speed
90°F 120°F
high fire
Settings can be from 85°F to
130°F with 20°F differential
Figure 15
HARMONY IIIT SERIES
total
differential =
20°F