Lennox International Inc. XP1906 Thermostat User Manual


 
506920−01 09/12
Page 18
Humidification and Dehumidification ModesĊhow they work
HUMIDIFICATION modes
BASIC & PRECISIONĊThese modes allow user control of RH between 15
and 45%. These conditions must be met for either mode to operate:
S humidification mode has been enabled, and
S the unit is in HEAT mode, and
S humidification demand exists (24V present at H), and
S BASIC mode also requires presence of heating demand [Y for HP
heat, or W for gas heat (W may be energized with G de−energized)].
DEW POINTĊ(Available only if Wi−Fi is operational or outdoor sensor is at-
tached)
Basic Dew Point ControlĊBasic Dew Point Control adjustment mode will
change the humidification setpoint based on the outdoor temperature and a
user−defined dew point adjustment setting.
Precision Dew Point ControlĊPrecision Dew Point Control adjustment
mode will operate when these conditions are met:
S humidification mode has been enabled, and
S the unit is in HEAT mode, and
S humidification demand exists (24V present at H).
DEHUMIDIFICATION modes
NOTE − Basic and Precision dehumidification modes are functions of the
HVAC system with NO external dehumidification devices installed. Humidi-
trol and Auxiliary Dehumidifiers do not use these modes.
In BASIC mode, dehumidification occurs if these conditions are met and sig-
nals 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. Also note that:
S Maximum overcool from cooling setpoint is 2ºF.
S Deadband temperature is limited to a minimum of 5ºF (instead of 3ºF
in BASIC or DISPLAY ONLY mode) because of 2ºF overcooling.
Humiditrol
®
or Auxiliary Dehumidifier mode requires:
NOTE − Systems using icomfortt and a dehumidifier − Dehum" jumper on
furnace/air handler control does not need to be cut when using with a icom-
fort Wi-Fit thermostat.
S Wi−Fi is operational or outdoor sensor is installed and set up
S dehumidification has been enabled on installer settings, and
S the unit is in COOL mode, (or if in AUTO, at least one thermostat cool-
ing call made prior to the dehumidification demand), and
S a dehumidification demand exists (RH above setpoint), and
S outdoor temp. below 95°F; indoor temp. above 65°F, and
S for HUMIDITROL, adjust Humiditrol
®
comfort parameters as follows:
MAX adj. − Indoor temp > 2°F above heating setpoint
MID adj. − Indoor temp >
HEAT Setpoint+COOL Setpoint
2
MIN adj. − Indoor temp > 2°F below cooling setpoint
Auxiliary Dehumidifier (stand alone dehumidifier)
When this option is selected, dehumidification will be allowed under the fol-
lowing conditions, provided there is NO call for humidification:
S In the absence of heating or cooling calls, or
S Simultaneous with blower only calls.
If the blower is required to operate while the auxiliary dehumidifier is running,
a separate wire must be installed from the auxiliary dehumidifier to the indoor
unit’s G thermostat input that will energize G when the auxiliary dehumidifier
is running (see wiring diagram on Page 61).
Auxiliary dehumidification is controlled by the thermostat dehumidification
demand.
NOTE − Refer to HCWH Dehumidifier Installation Instructions for installation
recommendations.