Honeywell TH8321 Product Data page 13

ISU Installer Setup
Number Name
No
215 Run Backup Heat
with Primary Yes
Equip Controls Fan
216 Backup Heat Fan
Tstat Controls Fan
None
217 Backup Heat Stage
2 U1
Electric
218 Backup Heat Type
Gas/Oil
No
219 External Fossil Fuel
Kit Yes
No
222 Economizer fault
Yes
"FDD"
T-stat terminal U1
222 Economizer Wiring
Table 2. Installer Setup (ISU) Table. (Continued)
Settings Default
No
Tstat Controls Fan
Default varies based
on previous selections
Electric
No
No
T-stat terminal U1
VISIONPRO® 8000 SMART THERMOSTAT
Residential,
Commercial
or Both
Both This ISU is only displayed when ISU 200 Heating
Equipment is Other.
When ISU 200 Heating Equipment is 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 200 Heating Equipment is Radiant Heat,
the thermostat keeps the Radiant Heat on when it
calls for Backup Heat.
Both This ISU is only displayed for conventional systems
when ISU 212 Backup Heat Type is Electric.
Backup Heat Fan Operation automatically defaults
to Equip Controls Fan when ISU 212 Backup Heat
Type is Gas/Oil.
Both 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.
U1 is a normally open dry contact when configured
for a stage of Heat. U1 requires power from a system
transformer or a separate transformer.
Both This ISU is only displayed when ISU 201 Heating
Equipment is Air to Air Heat Pump, Geothermal or
Geothermal Radiant and there is at least one stage of
backup heat.
See "Heat Pump and Backup Heat Operation"
beginning on page 55.
Both This ISU is only displayed when ISU 201 Heating
Equipment is Air to Air Heat Pump, Geothermal or
Geothermal Radiant and ISU 218 Backup Heat Type
is Gas/Oil.
Commercial If your code requires that the thermostat display an
alert when the economizer is sending a fault code,
select "Yes". When this is done, the economizer will
need to be wired as shown in Fig. 229 on page 87.
Commercial Only shown if "economizer fault FDD" is set to yes.
This setting is to inform installer only. It is not
adjustable. See economizer with fault wiring, Fig.
229 on page 87.
13
Notes
33-00096—04