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Dehumidification
(continued)
Humiditrol
®
Enhanced Dehumidification Acces-
sory
If a Humiditrol
®
EDA is present in the equipment at hand,
then the ComfortSense
®
Model L7742U thermostat must
be configured to properly operate the Humiditrol
®
EDA as
follows (see Figure 15 [Page 22] for the Humiditrol
®
EDA
operation flowchart):
From the OPTIONS screen, select INSTALLER SET-
TINGS. Scroll to HUMIDITY SETTINGS and press EN-
TER; select DEHUMIDIFY.
HUMIDITY MODE
HUMIDIFY
DEHUMIDIFY
|
|
Scroll to HUMIDITROL and press ENTER.
DEHUM MODE SETTING
DEF(OFF)
HUMIDITROL
Set the dehumidification setpoint; then press SAVE.
DEHUM SETPOINT
DEFAULT (5O%)
45%
Check the HUMIDITY SETTINGS in user settings to con-
firm that the user has control of the dehumidification set-
ting.
The ComfortSense
®
Model L7742U thermostat is now
configured to operate the Humiditrol
®
accessory.
NOTE − Humiditrol
®
EDA operation requires use of an out-
door sensor. If sensor is not connected and Humiditrol
®
EDA is enabled, OUTDOOR SENSOR REQUIRED" is
displayed in the information display.
ComfortSense
®
Model L7742U thermostat
operation with Humiditrol enabled
Cooling only
Dehumidification will only occur if:
S
a dehumidification demand is present,
S
a cooling demand is not present,
S
outdoor temperature is less than 95ºF,
S
indoor temperature is not cooler than 65ºF or cooler
than the heating se 2ºF (
IF
the difference be-
tween cooling and heating setpoints is greater than the
deadband).
In this case, 24 VAC is removed from the D" terminal and
Y1 & Y2" terminal (if available) becomes activated with
24VAC. This cycles the indoor variable speed motor to the
dehumidification speed and cycle Y2 ON" to the outdoor
unit. Cooling has priority over Humiditrol
®
calls.
Heating only
Thermostat will cycle heating ON" and
OFF to maintain heating setpoint. Dehumidification func-
tions are disabled.
Autochangeover
Dehumidification will only occur if a
dehumidification demand is present, a cooling demand is
not present, outdoor temperature is less than 95
°
F, indoor
temperature is above 65
°
F and the indoor temperature is
not cooler than 2ºF above heating setpoint.
In this case, the 24 VAC is removed from the D" terminal
and the Y1 & Y2" terminal (if available) becomes activated
with 24VAC. This will cycle the indoor variable speed motor
to the dehumidification speed and cycle Y2 ON" to the out-
door unit. Cooling calls have priority over Humiditrol
®
calls.
Humiditrol
®
mode is allowed to overcool up to 2
°
F above
the heating setpoint.
Note: If the last thermostat demand was a heating de-
mand, the thermostat does not require a cooling demand
before Humiditrol
®
operation.
Humidification Sensor Fault
If the humidification sensor fault occurs, then the H termi-
nal becomes inactive, and the D terminal goes to 24V.
Dew point adjust is only available when an outdoor sensor
is attached.
Other Humiditrol
®
EDA Notes:
If the outdoor sensor is disconnected while HUMIDITROL
is enabled, the thermostat will not allow operation in dehu-
midification mode.
Set point range: 45 to 60% Relative Humidity (RH). Facto-
ry default − 50%.
Relative Humidity controls to within 2% on either side of
RH set point.
When the D" terminal is activated with 24VAC, dehumidifi-
cation is inactive.
BASIC, PRECISION and HUMIDITROL
modes are deac-
tivated by default from the factory.
As a precaution, regardless of how low the heating setpoint
has been set, Humiditrol
®
dehumidification is inhibited be-
low 65
º
F indoor temperature.
