Economizer And Time Of Day (Tod) Operation; Pre-Occupancy Purge; Time Of Day (Tod) - Honeywell THX9321 Prestige 2.0 Product Data

®
THX9321 PRESTIGE 2.0 AND THX9421 PRESTIGE
Economizer and Time of Day (TOD)
Operation
Economizer
The thermostat controls an economizer module to provide
ventilation during occupied periods and free cooling when
outdoor conditions are favorable. In some climates the cooling
system may run several hours when it may not be required to
maintain indoor comfort. When outdoor conditions are
favorable, ventilation with outdoor air can achieve the same
level of comfort at lower cost. Table 9 explains how the
Economizer Module is controlled by the thermostat.
The thermostat works with the Jade W7212 Economizer
Module for conventional systems and the Jade W7213 and
W7214 Economizer Modules for heat pump systems.
Table 9. Economizer Operation.
Thermostat Mode Equipment Operation
Occupied Heat/Cool/Fan running
Occupied Heat/Cool/Fan running
temporarily
Occupied Heat/Cool/Fan NOT
running
Occupied Heat/Cool/Fan NOT
temporarily running
Pre-occupancy Fan running
purge
Unoccupied Cooling system running
Unoccupied Cooling system running
temporarily
Standby Cooling system running
Unoccupied Cooling system NOT
running
Unoccupied Cooling system NOT
temporarily running
Standby Cooling system NOT
running
Non-programmable Fan running
Non-programmable Fan NOT running
68-0311—02
®
IAQ WITH EIM

Time of Day (TOD)

The thermostat can be set up for a Time of Day output in the
installer setup. This output is commonly used to control lighting
panels, turning them on for occupied periods and off for
unoccupied periods. Table 10 explains how the TOD feature
works with various thermostat modes.
Occupied
Occupied temporarily
Temperature overrides
Unoccupied
Unoccupied temporarily
Standby
Non-programmable
A-L/A terminal:
Economizer
The Economizer Module and Time of Day output connect to
the A-L/A terminal at the thermostat or EIM and are set up at
ISU 2220.
ON
OFF

Pre-Occupancy Purge

The thermostat can be set up for Pre-Occupancy Purge in the
ON
installer setup (ISU 4010). When setup for Pre-Occupancy
Purge, the thermostat runs the fan 1 to 3 hours before each
occupied period to provide a comfortable workplace upon
OFF
arrival. Options are Off and 1 to 3 hours.
126
Table 10. TOD Operation.
Thermostat Mode
Fig. 305.
Fig. 306.
A-L/A terminal:
TOD
ON
OFF