Spec Sheet

Table Of Contents
THX9321 PRESTIGE
®
2.0 AND THX9421 PRESTIGE
®
IAQ WITH EIM
85 68-0311—07
Installer options
Installer Options require a password and should only be
changed by a qualified technician.
To prevent unintended changes or damage to your
equipment, do not change these options yourself.
Fig. 145.
Using the temperature display
In some circumstances, the temperature displayed on the
Home screen may not match the temperature near the
thermostat.
If your system is set up to use remote indoor sensors, it
may be reading a sensor in another location.
Fig. 146.
Using the humidity display
In some circumstances, the humidity displayed on the
Home screen may not match humidity near the
thermostat.
Some systems are set up to use two sensors, one to
control humidification, the other for dehumidification.
These sensors are often installed in different locations.
Depending on how your thermostat was installed, the
thermostat Home screen will display humidity readings
from only one sensor.
Fig. 147.
UNIVERSAL OUTPUTS
(U1, U2, U3)
U1, U2, U3 are universal outputs that can be setup to
control IAQ equipment and a stage of heating or cooling in
the Installer Setup. Setup options are listed below. See
THX9321 Thermostat Wiring Diagrams Using Universal
Relays to Control Heating or Cooling” beginning on
page 145 for more information.
Universal Output Options
THX9421 with Equipment Interface Module (U1, U2, U3):
Humidification (ISU 8030)
Dehumidification (ISU 9040)
Ventilation (ISU 10020)
Cool Stage 3 (ISU 2080)
Cool Stage 4 (ISU 2090)
Geothermal Radiant Heat (ISU 2030, 2040)
THX9321 Thermostat Only (U1, U2)
Humidification (ISU 8030)
Dehumidification (ISU 9040)
Ventilation (ISU 10020)
Cool Stage 3 (ISU 2080)
Cool Stage 4 (ISU 2090)
Conventional Heat Stage 3 (ISU 2100, 2140)
Backup Heat Stage 2 for Heat Pumps (ISU 2170)
Geothermal Radiant Heat (ISU 2030, 2040)
MENU
Installer Opons
72
INDOOR
Temperature reading
depends on location
of sensor
45% Humidity
Humidity reading
depends on location
of sensor.