Auto-Zone Control Systems Auto-Zone Basic Systems Installation & Operation (Version 02C) - Manual (Page 14)

Section 1 Auto-Zone Basic
1-8 Design Guide
Design Guide
There are six basic steps to designing an Auto-Zone Basic Control System:
1. Zoning
2. Sizing the Central Unit
3. Duct Design Considerations
4. Room Air Motion / Diffuser Selection
5. Bypass Damper Sizing
6. Sizing Zone Dampers
Step #1 - Zoning
Determine the number of zones. A single air handler unit can have no more than 16
zones. If the number of zones exceeds 16, then more than one Zone Manager will be
required. Consider using the Auto-Zone Plus system if more than one Zone Manager is
required.
The primary precaution to be taken in applying the Auto-Zone Basic Control System is to
select the zoning so that no zone will be at maximum (design) heating (or cooling) load
when any other zone requires the opposite temperature air to satisfy its load. For
example, depending on the wall, ceiling, floor material, and location within the building
(e.g. top or middle floor), a typical floor of a building usually has a minimum of 9
distinct temperature or control zones that are affected uniquely by the outdoor load.
These zones are depicted in Figure 1-2.
Depending on the size of the building and partition layout, some of these zones may
overlap or be insignificant from a zoning standpoint. For example, Zone 10 could be
multiple conference or computer rooms where additional zoning would be required, or it
could be as small as a corridor where no zoning is required. Similarly, zones 4 and 5
could have no external windows and no partitions between them and could be considered
a single zone. Zone 3 could be divided into multiple offices with full partitions between
them, thus requiring separate Zone Controllers because of different internal loads, but the
same external load.
Generally, the greater the number of individual Zone Controllers there are, the greater the
comfort. The designer will have to look at the specific building, balancing the costs of
multiple zones with the added comfort possible with multiple zones, to match the owner's
requirements.