17
INTELLIZONE2 INSTALLATION MANUAL
IntelliZone2 Confi guration cont.
Zone Configuration
Zone configuration allows the selection of the zone size and
the zone priority. The zone can be selected by touching the
upper right screen text noting the zone. In this way you can
cycle thru all of the active zones to view the configuration.
You must select a zone percentage before you can
configure the next zone. Select “Next Zone” for next zone
configuration.
Zone Percentage
Selecting the zone percentage can also be calculated by
using the IntelliZone2 Design software. This percentage
represents an approximation of the maximum heating or
cooling load percentage of the zone and thus to a certain
extent volume of airflow. The IntelliZone2 allows 0, 25, 45,
and 70% selections. Some general rules to follow in this
selection procedure are as follows:
•
Pick the larger percentage (45% or 70%) for major
living areas such as family rooms, etc.
•
Pick the smaller percentage for minor living areas such
as dens or bedrooms.
•
Pick a larger percentage if more branches are required
than the load indicates due to large area per load (i.e.
unfinished insulated basement).
•
The IntelliZone2 Design software should be used to aid
in the selection and calculation of design cfm.
•
The IntelliZone2 determines modes as a proportion of
the total demand. A simple example of this to begin
with is a two-zone system in the cooling mode. If each
zone is set at 70% we have the following scenario:
Zone 1 = 50%
Zone 2 = 50%
NOTE:
All Zone % calculations are ‘normalized using
the following process: We now must determine what
percentage of the total load each zone represents. To
perform this operation, add the two zones together 70 + 70
= 140. One zone would then be 70/140 or 50%.
The IntelliZone2 then reduces the total demand based
upon thermostat demand. A “Y1” call in the above example
will result in one half of the zone demand in this case 1/2
of 50% for a 25% system demand. A common complaint is
insufficient cooling when only one zone is calling for cooling.
The IntelliZone2 will not initiate a “Y2” output to the unit
until it senses a 50% total system demand (This is when the
IntelliZone2 is set for normal upstaging). If the IntelliZone2 is
set for quicker upstaging it drops the total system demand
required to 40% to initiate a Y2 output.
By this example, it will require a “Y2” call from one zone
(50%) and a “Y1” call from the second zone (25%). This will
give us a total system demand of 50% + 25% = 75%. System
demand for three- and four-zone systems are computed in
the same manner.
Heating demand is determined in the same manner, but
we now have a third stage instead of two for cooling. The
IntelliZone2 assigns values as follows:
Y1
=
40%
Y2
=
80%
Y3
=
100%
We know from the previous example that the IntelliZone2
will initiate a “Y2” output to the compressor when it is set to
normal upstaging and 50% of total demand is needed. It will
issue a “W” call to the unit when there is a 90% total demand.
It is a common assumption that if you have a house with
two zones equally divided each zone should be set at an
equal amount, usually 70%. As can be seen in the above
example, it will take a “Y3” call from one zone as well as a
“Y2” call from the second zone to obtain auxiliary heat.
This is a simple example, but three- and four-zone systems
are calculated in the same manner. Blower speeds are also
assigned upon the percentage of system demand and a
complete understanding of this process is not necessary
for day-to-day decisions. As a serviceman, the temptation
arises, in some instances, to influence the logic of the board
by jumping “Y1” and “Y2”. While this will create a quicker
response, the ductwork of that zone must be capable of
handling the cfm delivered by the unit (i.e., if a “Y2” signal
is given to the unit, can the ductwork handle the total cfm
of the unit).
When setting up a new system remember that if you have
unused zones they must be set to zero. If they are not, the
setting that they have will be included in the total demand
preventing the other zones from operating correctly, as
there will be no inputs on those zones.
