Lennox Harmony III Installation Instructions Manual page 8

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.
Zone Control Board Jumper Banks
HEATING STAGING
JUMPERS
coolING STAGING
JUMPERS
continuous air reduction
JUMPERS
heating air reduction
JUMPERS
Figure 10
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%.
Typical Air Selection Jumper Pin Settings
ZONE 1
Pin shown with
jumper on
ZONE 1 AT 10%.
Pin shown with
jumper on
ZONE 2 AT 0%
(allows min. cfm
airflow).
ZONE 2
NOTE − Only zones 2,
3, & 4 have an OFF
setting.
Figure 11
NOTE − If replacing a Harmony II
maintain equivalent air settings when setting up the
Harmony IIIt system.
505023M 04/06
PIAB
JUMPERS
ZONE 3
PIAB PIAB
ZONES 3
AND 4 ARE
SHOWN
NOT USED
(JUMPERS
ZONE 4
SET ON
PIAB PIAB
OFF").
®
system, use table 3 to
Air Jumper Positions Conversion Chart
Model
®
25
Harmony II
Harmony IIIt
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.
Air Delivery (CFM) Scale
PIAB = 0% Min. CFM
0 CFM
FIXED BAND
Motor runS AT MINIMUM BLOWER SPEED
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 − A PIAB 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:
Maximum CFM
D
(High cool jumper setting)
Minimum CFM
D
D Required CFM (zone 1) 1020
Determine PIAB Jumper Settings Example
Formula:
PIAB = (Required CFM − minimum CFM)
(Maximum CFM − minimum CFM)
PIAB = (1020 − 720)
(2220 − 720)
300
PIAB =
1500
PIAB
= 20%
=
Page 8
Table 3
Equivalent Positions (%)
35 45 55 65
0 10 30 40 50
PIAB = 100% Max. CFM
ADJUSTMENT BAND
Figure 12
2220
720
Table 4
75 85 95
70 80 90
Max. CFM
x 100
x 100
x 100