Lennox Harmony III, Installation, Setup And User Manual

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PIAB = [(Required CFM - Minimum CFM) / (Maximum CFM - Minimum CFM)] * 100
Sample CFM Required
Minimum Maximum Minimum
Sample PIAB = ([___920 - 450 ] / [ 2000 - 450 ]) x 100
= =
Sample PIAB = ([ 470 ] / [ 1550 ]) x 100
=
Sample PIAB = [ 0.303 ] x 100 = 30 %
Figure 10. PIAB Calculation Example
example example CFM CFM values values
Require Requiredd CF CFM M CFM CFM
Zon Zonee 11 Zone Zone 22 Zone Zone 33 Zone Zone 44 Min. Min. Max. Max.
1020 1020 1500 1500 720 720 OFF OFF 720 720 2200* 2200*
*High cool jumper settin *High cool jumper settingg
PIA PIABB formula formula
100 100
(R (Reeq’ q’dd CFM CFM −− min. C min. CFM FM))
(Max. CFM (Max. CFM −− min. CFM min. CFM))
xx
U Ussiing e ng exxaam mpplle v e vaalue luess abo abovve, e, fifind nd PIAB PIAB ffoorr Zone 1 Zone 1::
PIA PIABB ((1102 0200 -- 772200)) = 30 = 3000 =.20 =.20 .. .. .. .. . . . . .. . . . . .. .. .. . . . . .. .. .. .. .. . . . . . . .. . . . . .. . . . . ..
(2220 - 720) =150 (2220 - 720) =15000 .. .. .. .. . . . . .. . . . . .. .. .. . . . . .. .. .. .. .. .. .. .. ..
PIAB Jumper setting PIAB Jumper setting % % .20 x 10 .20 x 1000 20% 20% .. .. .. .. . . . . .. .. .. . . . . .. .. . . . . . . .. . . . . ..
Figure 11. Determine PIAB Jumper Settings
1.10.6. Continuous Air Reduction Jumpers
During continuous fan mode without either a heating or cooling demand, the blower
runs at the total percentage of the CFM jumper settings of the zones calling for
continuous fan (not to exceed 100% of blower capacity). A continuous air reduction
jumper allows the blower speed to be reduced by a percentage during continuous
fan mode.
The selections are 75%, 50%, 25% and 0%. At the factory, the jumper is set on
0%. Set the jumper to the position equal to the amount of continuous air reduction
desired.
NOTE:
If the calculations using a reduction percentage indicated a resulting CFM
lower than the blower’s minimum CFM rating, the blower will deliver its
minimum CFM
1.10.7. Heating Air Reduction Jumpers
NOTE: For heat pump applications, ALWAYS set the jumper on 0%. High head
pressures may result if air is reduced during heating mode.
NOTE: For use in warm-climate areas where units have high cooling capacity with
low heat capacity, ALWAYS set the jumper on 0%.
The heating air reduction jumper enables the blower speed, during heating only, to
run at a reduced rate compared to 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.
CONTINUOUS HEATING
0%
20%
40%
75%
50%
0%
25%
factory
settings
shown
heating jumper
Must be set on 0%
for heat pump
application
Figure 12. Heating Air Reduction Jumpers
1.10.8. Heat/Cool Staging
Heating/Cooling staging jumpers prevent any rapid staging of the equipment. This
section shows the recommended settings for heating/cooling staging temperatures
and explains the temperature differentials for different equipment configurations.
In the diagrams, sine waves indicate which stage operates during the rise and
fall of discharge air temperature for the different heating/cooling staging jumpers.
Recommended jumper settings are shown in bold type.
1.10.8.1. Heating Staging Temperature Jumper
Heating Staging temperature jumpers are used to set the temperature at which the
second stage heating equipment comes ON. Its selections range from 85 - 130 (°F).
The setting 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 temperature, 2nd-stage operation ceases and 1st-stage
heating resumes until the temperature again falls below the jumper set point.
NOTE: For SLP98 furnaces only, the furnace ignition control will automatically
adjust firing rate without a second stage heat demand to match the blower
airflow (CFM) requested by the Harmony III zoning system.
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.