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

®
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 running *
Occupied Heat/Cool running *
temporarily
Occupied Heat/Cool NOT running *
Occupied Heat/Cool NOT running *
temporarily
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- Fan running
programmable
Non- Fan NOT running
programmable
* Fan (G) always energized during occupied & occupied tem-
porary modes.
68-0311—08
®
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
The Economizer Module and Time of Day output connect
terminal:
to the A-L/A terminal at the thermostat or EIM and are set
Economizer
up at ISU 2220.
ON

Pre-Occupancy Purge

OFF
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
ON
workplace upon arrival. Options are Off and 1 to 3 hours.
OFF
126
Table 10. TOD Operation.
Thermostat Mode
Fig. 310.
Fig. 311.
A-L/A
terminal: TOD
ON
OFF