THX9321 PRESTIGE
®
2.0 AND THX9421 PRESTIGE
®
IAQ WITH EIM
27
68-0311—02
2130
Backup Heat
Stages
0 - 2
1
Both
No
This ISU is only displayed when a backup
heat source is selected at ISU 2120 Backup
Heat Type.
Maximum of 2 Backup Heat stages.
2140
What Terminals are
Wired to Backup
Heat?
None
U1
U2
Default varies
based on
previous
selections
Both
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 3
conventional heat stages. When there are a
total of 3 conventional heat stages, the last
stage of heat 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.
2150
Backup Heat
Operation
NOT Allowed to Run with Primary
Heat
Allowed to Run with Primary Heat
NOT allowed to
run with
Primary Heat
Both
No
This ISU is only displayed when ISU 2010
Heating Equipment Type is
Hot Water Fan
Coil, Electric Forced Air
or
Other.
W
hen ISU 2010 Heating Equipment Type is
Hot Water Fan Coil,
Electric Forced Air
or
Other,
you can select how the Backup Heat
operates. The thermostat can be setup to
keep the primary heat source on when it
calls for Backup Heat or the thermostat can
be setup to turn off the primary heat source
when it calls for Backup Heat.
When ISU 2010 Heating Equipment Type is
Hot Water Radiant Heat
, the thermostat
keeps the Hot Water Radiant Heat on when
it calls for Backup Heat.
When ISU 2010 Heating Equipment Type is
Steam
, the thermostat keeps the Steam
Heat on when it calls for Backup Heat.
2160
Backup Heat Fan
Operation
No Fan
Equipment Controls Fan
Thermostat Controls Fan
Thermostat
Controls Fan
Both
No
This ISU is only displayed for conventional
systems when ISU 2120 Backup Heat Type
is
Electric Forced Air
,
Hot Water Fan Coil
or
Other
.
Backup Heat Fan Operation
automatically
defaults to
Equipment Controls Fan
when
ISU 2120 Backup Heat Type
is
Standard
Efficiency Gas Forced Air, High Efficiency
Gas Forced Air
or
Oil Forced Air.
No Fan
is only displayed when ISU 2120
Backup Heat Type
is
Other.
Table 4. Installer Setup (ISU) Table. (Continued)
ISU
Number
Installer Setup
Name
Settings
Default
Residential,
Commercial
or Both
Requires
EIM
Notes