Auto-Zone Control Systems Auto-Zone Basic Systems Installation & Operation (Version 02C) - Manual (Page 59)

Auto-Zone Basic Section 2
Installation and Wiring 2-29
Zone Controller Auxiliary Relay Board
Operation
Relay #1 - Parallel Fan
If the zone is in cooling mode or vent mode, the parallel fan relay will activate any time
the zone temperature drops 0.5°F below the heating setpoint. It de-activates when the
temperature rises 0.5°F above the heating setpoint. The space temperature must be below
the AUX HEAT setpoint in the occupied mode before the Parallel Fan relay can be ener-
gized.
Relay #2 - Box Heat
If the zone is in cooling mode or vent mode, the box heat relay will activate any time the
zone temperature drops 1.5°F below the heating setpoint. It de-activates when the tem-
perature rises to within 1.0°F of the heating setpoint. Box heat is not allowed to activate
in the heating mode when there is hot air being supplied by the air handler. This output
was intended to allow zone re-heat while the Zone Manager is satisfying cooling de-
mands in other zones. The space temperature must be below the AUX HEAT setpoint in
the occupied mode before the Box Heat relay can be energized.
Relay #3 - Aux Heat
In the occupied mode, the aux heat relay will activate any time the zone temperature is
0.5°F below the aux heat setpoint. It de-activates when the temperature rises 0.5°F above
the aux heat setpoint. In the unoccupied mode, the aux heat uses the unoccupied heating
setpoint with the same deadband values mentioned above. This prevents the zone from
maintaining the same aux heat setpoint at night that it does during the daytime.
This output was intended to allow zone heating, to augment the normal heating mode,
and also to allow a zone to attempt to satisfy its own heating needs before creating a heat-
ing demand at the Zone Manager.
Relay #4 - Series Fan
The series fan relay is energized any time the main fan is running. This includes occu-
pied and unoccupied modes. In the unoccupied mode, the fan can only start when the
zone damper is closed. The controller checks to be sure the damper is closed before start-
ing the fan.