Honeywell THX9321 Prestige 2.0 Product Data page 28

®
THX9321 PRESTIGE 2.0 AND THX9421 PRESTIGE
ISU Installer Setup
Number Name
2170 What Terminals are
Wired to Backup
Heat - Stage 2?
2180 Backup Heat Type
2190 External Fossil Fuel
Kit
2200 Backup Heat
Operation
68-0311—02
Table 4. Installer Setup (ISU) Table. (Continued)
Settings
None
U1
U2
Electric Forced Air
Standard Efficiency Gas Forced Air
High Efficiency Gas Forced Air
Oil Forced Air
Hot Water Fan Coil
Hot Water Radiant Heat
Other
Thermostat Controls Backup Heat
External Fossil Fuel Kit Controls
Backup Heat
NOT allowed to Run with Heat
Pump
Allowed to Run with Heat Pump
®
IAQ WITH EIM
Residential,
Commercial
Default or Both
Default varies Both
based on
previous
selections
Electric Forced Both
Air
Thermostat Both
Controls
Backup Heat
Default varies Both
based on
previous
selections
28
Requires
EIM Notes
No THX9321 Thermostat Only:
This ISU is only displayed on the THX9321
thermostat when it is wired directly to the
equipment (Equipment Interface Module is
NOT used).
The thermostat can support up to 2 backup
heat stages for heat pump applications.
When there are 2 backup heat stages,
backup heat stage 2 must be wired to U1 or
U2.
U1 and U2 are normally open dry contacts
when configured for a stage of Heat. U1
and U2 require power from a system
transformer or a separate transformer.
No This ISU is only displayed when ISU 2010
Heating Equipment Type is Air to Air Heat
Pump, Geothermal Heat Pump or
Geothermal Radiant Heat and there is at
least one stage of backup heat.
See "Heat Pump and Backup Heat
Operation" beginning on page 100.
No This ISU is only displayed when ISU 2010
Heating Equipment Type is Air to Air Heat
Pump, Geothermal Heat Pump or
Geothermal Radiant Heat and ISU 2180
Backup Heat Type is Standard Efficiency
Gas Forced Air, High Efficiency Gas
Forced Air or Oil Forced Air.
No This ISU is only displayed when ISU 2010
Heating Equipment Type is Air to Air Heat
Pump, Geothermal Heat Pump or
Geothermal Radiant Heat and ISU 2180
Backup Heat Type is Hot Water Fan Coil or
Other.
Not Allowed to Run with Heat Pump: The
thermostat turns off the heat pump when it
calls for backup heat.
Allowed to Run with Heat Pump: The
thermostat keeps the heat pump on when it
calls for backup heat.