GENERAL
Page 10
505023M 08/11
Zone Control Panel Jumpers (Heat/Cool Staging)
Heating/Cooling staging jumpers prevent any rapid stag-
ing of the equipment. This section shows the recom-
mended settings for heating/cooling staging temperatures
and explains the temperature differentials for different
equipment configurations. In the diagrams, sine waves in-
dicate which stage operates during the rise and fall of dis-
charge air temperature for the different heating/cooling
staging jumpers. Recommended jumper settings are
shown in bold type.
Heating Staging Temperature Jumper
Heating Staging temperature jumpers are used to set the
temperature at which the 2nd−stage heating equipment
comes ON. Its selections range from 85 − 130 (°F). The set-
ting has a built-in differential of 20°F (except as described
when 140DAS jumper is used).
During operation, when the discharge air temperature falls
below the jumper setpoint, 2nd-stage heating begins. If the
discharge air temperature reaches the differential temper-
ature, 2nd-stage operation ceases and 1st-stage heating
resumes until the temperature again falls below the jumper
set point.
NOTE − For G71MPP and SLP98 furnaces only, the fur-
nace ignition control will automatically adjust firing rate
without a 2nd stage heat demand to match the blower air-
flow (CFM) requested by the Harmony IIIt zoning system.
See Operation with G71MPP and SLP98" on page 26 for
additional information.
Heat Pump (range: 85 − 110°F, recommended: 90). The
maximum discharge air temperature at which the heat
pump/electric heat is allowed to run is fixed at 135°F.
105F
1ST STAGE2ND STAGE
TIME "
2ND STAGE
Discharge Air Temperature ºF
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
staging jumper position.
Gas Furnace with 160°F upper limit (range: 100 − 130;
recommended: 120). The maximum discharge air temper-
ature at which the furnace may run is fixed at 160°F.
Discharge Air Temperature ºF
1ST STAGE2ND STAGE
TIME "
2ND STAGE
Gas Furnace w/140F DAS
jumper (range: 100 − 130;
recommended: 120). When
the 140F DAS jumper is in
place (as shown to the
right), the maximum dis-
charge air temperature at
which the furnace may run
is fixed at 140°F. (Note the
140F DAS jumper’s impact
on the differential at 120
and 130 settings):
1ST STAGE2ND STAGE
TIME "
2ND STAGE
Discharge Air Temperature ºF
Cooling Staging Temperature Jumper
Cooling Staging temperature jumpers are used to set the
discharge air temperature at which 2nd−stage cooling
comes on. It is selectable between 50°, 55° and 60°F. A 7
degree total differential is associated with this staging tem-
perature, beginning at the jumper setpoint, and extending
to 7 degrees above the setpoint.
For any jumper setting, if the discharge air should fall to
45°F and any zone still demands cooling, the compressor
will not run leaving only the blower to operate until the dis-
charge air once again rises to 50°F and the 5 minute com-
pressor OFF delay has been satisfied. For this reason, and
to better satisfy latent loads, the jumper recommended
setting is 50.
1ST STAGE 2ND STAGE
67F
62F
57F
1ST STAGE
TIME "
Discharge Air Temperature
ºF
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