Lennox ComfortSense 7500 Commercial - Advanced Humidity and Economizer Controls; Dehumidification in Heat Modes; Economizer System Integration

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In this case, 24VAC is removed from the D terminal
and Y1 and 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. Humiditrol
®
mode is
allowed to over cool up to 2ºF above the heating set
point.
Heat only—Thermostat will cycle heating ON and
OFF to maintain heating set point. Dehumidification
functions are disabled.
Heat/Cool—Dehumidification will only occur if a
dehumidification demand is present, a cooling
demand is not present, outdoor temperature is less
than 95ºF, indoor temperature is above 65ºF and the
indoor temperature is not cooler than 2ºF above
heating set point.
Note: If the last thermostat demand was a heating
demand, the thermostat does not require a cooling
demand before Humiditrol
®
operation.
Humidity Sensor Fault
If the humidity sensor fault occurs, the thermostat
shuts off dehumidification.
Other Humiditrol
®
EDA Notes
If the outdoor sensor is disconnected while
HUMIDITROL is enabled, the thermostat will not
allow operation in dehumidification mode.
Set point range: 45 to 60% Relative Humidity (RH).
Factory default - 50%.
Relative Humidity controls to within 3% on either
side of RH set point.
When dehumidify mode is in NORMAL or MAX or,
HUMIDITROL, "D" terminal works in reverse logic.
NORMAL, MAX and HUMIDITROL modes are
disabled by default from the factory.
As a precaution, regardless of how low the heating
set point has been set, Humiditrol
®
dehumidification
is inhibited below 65ºF indoor temperature.
Economizer
Economizer control means that for every period in
the day that the unit is in occupied mode, the
occupancy out Ec (relay output) shall be energized
whenever there is a demand for fan (G is active).
The thermostat does not directly control the damper
position. The output from the thermostat will be
wired to an economizer controller or a unit controller
which will control the position of the damper.
Table 3. Terminal Ec Operation
Effective Oc
cupancy
Call for
Cooling
Terminal EC
State
Occupied - Energized
Unoccupied
Yes De-Energized
No De-Energized
Override - Energized