Honeywell PRESTIGE THX9321 - Manual (Page 126)

THX9321 PRESTIGE ® 2.0 AND THX9421 PRESTIGE ® IAQ WITH EIM
68-0311—02 126
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.
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.
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.
Fig. 305.
Pre-Occupancy Purge
The thermostat can be set up for Pre-Occupancy Purge in the
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
arrival. Options are Off and 1 to 3 hours.
Fig. 306.
Table 9. Economizer Operation.
Thermostat Mode Equipment Operation
A-L/A terminal:
Economizer
Occupied Heat/Cool/Fan running
ON
Occupied
temporarily
Heat/Cool/Fan running
Occupied Heat/Cool/Fan NOT
running
Occupied
temporarily
Heat/Cool/Fan NOT
running
Pre-occupancy
purge
Fan running
Unoccupied Cooling system running
Unoccupied
temporarily
Cooling system running
Standby Cooling system running
Unoccupied Cooling system NOT
running
OFF
Unoccupied
temporarily
Cooling system NOT
running
Standby Cooling system NOT
running ON
Non-programmable Fan running
Non-programmable Fan NOT running
OFF
Table 10. TOD Operation.
Thermostat Mode
A-L/A terminal:
TOD
Occupied
ON Occupied temporarily
Temperature overrides
Unoccupied
OFF
Unoccupied temporarily
Standby
Non-programmable