Set Up Dehumidification With Cooling System - Honeywell TH8320R1003 Vision Pro 8000 Product Data

Cooling Droop (ISU 908 and 910): This option uses the
cooling system to lower the temperature up to 5° F below the
current cool setpoint until the desired humidity is reached. The
Dehum Over Cooling Limit range is from 1° to 5° F.
Cooling Droop with Minimum On Time (ISU 908, 909, and
910): This method uses both options above to reduce humidity
while maintaining a comfortable temperature.
Reheat (ISU 908): This option allows heating to run during
dehumidification to help maintain a comfortable temperature. If
only cooling stage 1 is used, during the "off" cycle, both cooling
and heating run at the same time as needed to dehumidify
without overcooling. This option cannot be used in the Heat
mode. This option is effective only if using a system with the A-
Coil located before the heating coil (heat exchanger). This
feature requires a conventional forced air heating system (gas,
oil, or electric) in the application.
NOTE: Reheat can be used on heat pump applications
that have a forced air backup heat source (gas,
oil, or electric). The thermostat will turn on the
first stage of forced air backup heat during
Reheat.
NOTE: Reheat can be used on systems where the A-Coil
is located after the heating coil (heat exchanger),
but it is not effective at removing humidity.
Reheat with Minimum On Time (ISU 908 and 909): This
method uses both Reheat and Minimum On Time options
above to reach the desired humidity level.
If set for A/C with Low Speed Fan, configure U1, U2, or U3 as
normally open or normally closed (ISU 905) and wire to the
Low Speed Fan terminal on the equipment. For example, if the
U1, U2, or U3 terminal is normally closed, it will open when the
thermostat calls for dehumidification.See "Wiring IAQ
Equipment or a Heat/Cool Stage to the Universal Terminals"
beginning on page 128.
NOTE: The thermostat will not lower the fan speed when
the second stage of cooling is on.
Set up Dehumidification With Cooling
System
Some screens shown in this section may not appear on the
thermostat, depending on how you set up dehumidification.
1. Select the Dehumidification Equipment in ISU 900. See
Fig. 209.
Fig. 209.
2. If optional remote wireless indoor sensors are installed,
you can choose which sensor you want to use for dehu-
midification control. For example, you can use one sen-
sor for humidification control, and another for
dehumidification. See "Wireless Indoor Sensor" begin-
ning on page 112 for more information.
3. If you are sensing humidity from two separate locations
(one for humidification and another for dehumidification),
you can select which humidity reading to display on the
home screen. See "Wireless Indoor Sensor" beginning
on page 112 for more information.
4. Select the terminals wired to the A/C with Low Speed
Fan or Hot Gas Bypass. See Fig. 212.
5. Select whether the U1, U2, or U3 terminals are Normally
Open or Normally Closed. See Fig. 213.
• Normally Open – contacts are normally open and will
close during a call for dehumidification
• Normally Closed – contacts are normally closed and
will open during a call for dehumidification.
87
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VISIONPRO 8000 WITH REDLINK™
Fig. 210.
Fig. 211.
Fig. 212.
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