Auto-Zone Control Systems Auto-Zone Plus Systems Installation & Operation (Version 03A) - Manual (Page 29)

Auto-Zone Plus Section 1
Design Guide 1-25
Auxiliary Heat Control
Options
The Auto-Zone Plus system offers the user a variety of methods to deal with zone heating
requirements. When deciding how to handle zone heating requirements the user should
consider the following:
• Does the rooftop unit have heat?
• Are you using fan powered boxes?
• Is auxiliary heat used such as baseboard or radiant ceiling panels?
If the zone has some type of heat, the user must consider how the heat is to be used.
Typical questions that should be asked:
Q:
Should the zone heat be used as a first stage where it will become active before a
heating demand is created at the rooftop unit?
A:
This mode is useful if you expect to have both heating and cooling demands at the
same time. The zone will use it’s own heat and allow the rooftop unit to continue to
provide cooling for other zones. This mode is also useful if the rooftop unit does not
have any heating capabilities.
Q:
Is the zone heat only to be used as a second stage, where it will be activated only if
the rooftop unit cannot maintain the space temperature, such as during very cold
weather?
A:
In this mode of operation the rooftop will examine the heating and cooling demands
and try to satisfy all of the zones by switching between heating and cooling as
required. The zone heat will only be activated if the zone temperature falls below a
selected limit.
Q: Should the zone heat be locked out if the rooftop unit is supplying warm air?
A:
In many instances it is desirable to use the rooftop heating whenever possible and
only use zone heat when the rooftop unit is in cooling or vent mode. This often
provides the most cost effective operation since zone heat is typically electric. This
mode of operation will lockout zone heat if the rooftop is delivering heated air.