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ComfortSense
t
Model L7742U Touch Screen 7−Day Programmable Thermostat
Dehumidification
INSTALLER SETTINGS
Dehumidification
(removing moisture from air) can occur only when the
thermostat is in
cool mode
. When a dehumidification demand is pres-
ent, a dehumidification signal (0VAC − open circuit) is present at the D
terminal. This is used to reduce the speed of the indoor blower during
dehumidification. At the same time, the Y1 and Y2 (if available) termi-
nals become activated with 24VAC. The H terminal is inactive (0VAC −
open circuit) during dehumidification.
NOTE − The D terminal is ALWAYS activated (24VAC) when the ther-
mostat is in HEAT or OFF mode; it is only inactive (0VAC − reverse log-
ic) during dehumidification.
Dehumidification adjustment will change the relative humidity (RH) set-
ting between 45 to 60% RH (default setting is 50% RH). The lower the
number, the more humidity will be removed from the air.
HUMIDITY SETTING
default OFF.
Installer settings must be turned on before the user will have
control over the humidity.
The mode selected determines how the user can adjust the relative hu-
midity (RH). The installer settings include BASIC, PRECISION, HUMI-
DITROL, and OFF.
Dehumidification Modes
In
BASIC
mode, dehumidification occurs if these conditions are met
and signals are present at specific terminals:
S
dehumidification has been enabled on installer settings, and
S
the unit is in COOL mode, and
S
dehumidification demand exists (RH above setpoint), and
S
cooling demand exists (Y1 energized).
In
PRECISION
mode, dehumidification occurs if all BASIC conditions
are true, except cooling demand may or may not be present. Maximum
over cool from cooling set point is 2ºF.
HUMIDITROL
mode requires:
S
outdoor sensor must be installed and setup
S
dehumidification has been enabled on installer settings, and
S
the unit is in COOL mode, (or if in AUTO, there has been at least
one thermostat cooling call made prior to the dehumidification de-
mand), and
S
a dehumidification demand exists (RH above setpoint), and
S
outdoor temperature is below 95°F, and
S
indoor temperature is above 65°F, and
S
the room temperature meets Humiditrol adjustment parameters
as follows:
D
MAX
adj. − Indoor temp > 2°F above heating setpoint
D
MID
adj. − Indoor temp >
HEAT SCOOL SETPOINT
2
D
MIN
adj. − Indoor temp > 2°F below cooling setpoint
Scroll to HUMIDITY SETTINGS; press ENTER. Press the box below
DEHUMIDIFY.
HUMIDITY MODE
HUMIDIFY
DEHUMIDIFY
|
|
Use up/down arrows to scroll to BASIC or PRECISION; press ENTER.
DEHUM MODE SETTING
DEF(OFF)
PRECISION
Default setting is 50% RH. Use up/down arrows to change the %RH;
press SAVE.
DEHUM SETPOINT
DEFAULT (5O%)
45%