Auto-Zone Control Systems Auto-Zone CV-C Controller Installation Guide (Version 01A) - Manual (Page 17)

Auto-Zone CV-C Section 2
Sequence of Operation 2-7
Heat Mode A heating demand is generated when the space temperature drops half the
amount of the Deadband Setpoint below the currently active Heating
Setpoint. The space is considered satisfied when it rises that amount above
the Heating Setpoint.
Fan Only Mode A Fan Only mode cause ALL outputs except for the fan to their inactive
state. It is exactly like the Off Mode except the fan is running. This mode
can be used to temporarily purge the space, etc.