Auxiliary relay sequence of operation – Auto-Zone Control Systems Auto-Zone Plus Systems Installation & Operation (Version 03A) User Manual

Page 59

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Auto-Zone Plus

Section

2

Design Guide

2-27

Auxiliary Relay Sequence of Operation

Relay #1 - Parallel Fan

If the Zone is in cooling mode or vent mode, the parallel fan can activate anytime the
zone temperature drops 0.5

°F below the heating setpoint. It de-activates when the

temperature rises 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 energized.

Relay #2 - Box Heat

If the Zone Manager is in cooling mode or vent mode then the box heat can activate
anytime the zone temperature drops 1.5

°F below the heating setpoint. It de-activates when

the temperature 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 handling unit.
This output was intended to allow zone re-heat while the Zone Manager is satisfying
cooling demands 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 can activate anytime 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 an attempt to satisfy its own heating needs before creating a Heating
Demand at the Zone Manager.

Relay #4 - Series Fan

The Series Fan runs anytime the Main Fan is running. This includes Occupied and
Unoccupied Modes. The fan can only start running when the Zone Damper is closed, so it
determines that the damper is closed before starting the fan.

Modulating Box Heat Available

Modulating Heat is available by using the OE322 Expansion Board but requires special
consideration. The OE322 board can provide a 0-10 VDC modulating signal for a
Modulating Hot Water Valve or an SCR Electric Heating Coil Controller. Please contact
WattMaster for more information.

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