TH8320U AND TH8321U TOUCH SCREEN PROGRAMMABLE THERMOSTATS
19
69-1706
ADVANCED FEATURES
Outdoor or Indoor Temperature Sensor
Allow outdoor or indoor temperature sensor to absorb the
air for a minimum of five minutes before taking a reading.
See the Sensor instructions for more information.
Special Heat Pump Features
Heat Pump with Fossil Fuel Auxiliary Heat (Dual
Fuel) and Outdoor Temperature Sensor
In this operation, there is no external fossil fuel kit (dual
fuel kit) installed; the thermostat controls this function.
1.
Choose correct heat pump application in Installer
Setup Number 0170.
2.
Choose
Fossil Fuel Option
as the backup heat
source in Installer Setup Number 0200.
3.
Choose
No External Fossil Fuel Kit Option
is
controlling back up heat in Installer Setup Number
0210.
4. Outdoor Temperature Sensor for Control
Option
is automatically chosen in Installer Setup
Number 0340 (0340 is not shown).
5.
Choose appropriate
Balance Point Temperature
in Installer Setup Number 0350.
OPERATION IN HEAT MODE ABOVE BALANCE POINT
(OUTDOOR TEMPERATURE)
When the outdoor temperature is above the selected
Balance Point Temperature (ISU 0350), only the
compressor operates and the fan (G terminal) energizes
when the thermostat calls for heat.
OPERATION IN HEAT MODE BELOW BALANCE POINT
(OUTDOOR TEMPERATURE)
When the outdoor temperature is below the selected
Balance Point Temperature (ISU 0350), only the Fossil
Fuel (auxiliary heat) operates and the fan (G terminal)
does not energize when the thermostat calls for heat.
OPERATION IN EMERGENCY HEAT MODE
The balance point (outside) temperature is not used in
the Emergency heat mode. When the thermostat is
moved to the Emergency Heat position, the compressor
is locked out. The first stage of heat is whatever is
connected to the E terminal. The second stage of heat is
what is connected to the Aux. terminal. Often there is
only one source of non-compressor heat and the E
terminal is jumped to the Aux. terminal.
Heat Pump with Electric Auxiliary (Backup) Heat
and Outdoor Temperature Sensor
1.
Choose correct heat pump application in Installer
Setup Number 0170.
2.
Choose Electric as
Auxiliary (Backup) Heat
Source
in Installer Setup Number 0200.
3.
Choose
Outdoor Temperature Sensor for
Control Option
in Installer Setup Number 0340.
4.
Choose
Compressor Lockout Temperature
in
Installer Setup Number 0350.
5.
Choose
Auxiliary Lockout Temperature
in
Installer Setup Number 0360.
NOTE: There is a 5°F deadband between the
Compressor and Auxiliary Heat Lockout
Temperatures
Operation in Heat Mode
When the outdoor temperature is below the Compressor
Lockout Temperature, only the Auxiliary Heat operates.
When the outdoor temperature is above the Auxiliary
Lockout Temperature, only the Compressor operates.
See Fig. 24.
Fig. 24. Heat Pump Operation with Lockout
Temperatures Set.
When the outdoor temperature is between the two
temperatures, both the Compressor and Auxiliary Heat
operate.
Operation in the Emergency Heat Mode
Once the thermostat is placed into the Emergency Heat
mode, the compressor and auxiliary lockout features are
turned off. In the Emergency heat mode, the compressor
is locked out. The first stage of heat is whatever is
connected to the E terminal. The second stage of heat is
connected to the Aux. terminal. Usually the emergency
and auxiliary heat sources are electric strip heat in these
cases.
Dehumidification Droop Control
The dehumidification control attempts to control to the
user's humidity setpoint by turning on the air conditioner.
In extremely high humidity conditions, the thermostat
keeps the air conditioner running for up to 3
°
F below the
temperature setpoint. It does this while trying to achieve
the desired humidity setpoint and balancing that with the
temperature setpoint.
35
M19950
COMPRESSOR
LOCKOUT
TEMPERATURE
AUXILIARY
LOCKOUT
TEMPERATURE
COMPRESSOR ONLY
BOTH COMPRESSOR AND
AUXILIARY HEAT
AUXILIARY ONLY
50
OUTDOOR TEMPERATURE
