Set Up Dehumidification With Cooling System - Honeywell Prestige 2.0 THX9421 Manual

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 9080 and 9090): 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 9050) 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 152.
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 9000.
See Fig. 240.
Fig. 240.
2. If optional remote wireless indoor sensors are
installed, you can choose which sensor you want to
use for dehumidification control. For example, you
can use one sensor for humidification control, and
®
THX9321 PRESTIGE 2.0 AND THX9421 PRESTIGE
another for dehumidification. See "Wireless Indoor
Sensor" beginning on page 132 for more informa-
tion.
3. If you are sensing humidity from two separate loca-
tions (one for humidification and another for dehu-
midification), you can select which humidity reading
to display on the home screen. See "Wireless Indoor
Sensor" beginning on page 132 for more informa-
tion.
4. Select the terminals wired to the A/C with Low Speed
Fan or Hot Gas Bypass. See Fig. 243.
5. Select whether the U1, U2, or U3 terminals are Nor-
mally Open or Normally Closed. See Fig. 244.
• 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.
111
®
IAQ WITH EIM
Fig. 241.
Fig. 242.
Fig. 243.
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