Lennox International Inc. l7742u Thermostat User Manual


 
506229−01 05/09
Page 6
Controlling the Fan Operation
Fan Modes
If backlight is not on continuous, press the screen
anywhere to turn on the backlight. Press the
OPTIONS tab to access the FAN mode control.
Press FAN button; repeated presses scroll through
all the modes, AUTO, ON, and CIRC (circulate).
S AUTOĊthe fan is following schedule.
S ONĊthe fan is NOT following the schedule and runs continuously
until it is changed from the OPTIONS screen.
S CIRCĊthe fan is following schedule and cycles during periods of
equipment inactivity. Cycle time is dependent on user settings
FAN CIRCULATE (Page 10).
If FAN mode displays AUTO and ON or CIRC was selected during
scheduling for the current period, the thermostat will indicate the current
fan mode in the information display (FAN ON or FAN CIRC).
In the CIRC mode, the user can cycle the fan for a programmed
percentage of active time per hour, during periods of equipment
inactivity (i.e., heating or cooling equipment not running). The fan is ON
for 5 minutes at a time. The user may change the percentage of ON time
that the fan is on (see FAN CIRCULATE [Page 10]):
Fan Program
The user can program the fan to be ON, AUTO, or CIRC during a
program event period. While scheduling the event, if the fan is set to
ON, it will remain on during the entire event. If it is set to CIRC, it will
circulate during equipment inactivity per user programmable cycles
(see FAN CIRCULATE, Page 10). If set to AUTO, the fan will come on
with the equipment to serve the heating/cooling demand and go off
accordingly.
NOTE − When the OPTIONS screen FAN mode is changed to ON or
CIRC, whatever was scheduled is ignored − the fan will either be ON or
it will CIRCULATE per the user−programmed intervals (USER
SETTINGS − FAN CIRCULATE (Page 10). When FAN − AUTO is
selected in the OPTIONS screen, the schedule IS followed.
In the CIRC mode, the user can cycle the fan for a programmed
percentage of active time per hour, during periods of equipment
inactivity (i.e., heating or cooling equipment not running). The fan is ON
for 5 minutes at a time. The user may change the percentage of ON time
that the fan is on (see FAN CIRCULATE [Page 10]):
Controlling the Schedule
If backlight is not on continuous, press the screen
anywhere to turn on the backlight.
From the HOME screen press SCHED; repeated
presses toggle the schedule ON and OFF. If ON, the
system follows the program developed by the user
(Page 7).
If OFF, the system operates as a non−programmable thermostatĊthe
user must make changes when desired. The autochangeover feature
continues to operate based on the manual user inputs.
The fan mode is displayed on the SCHEDULE screen when program-
ming the thermostat and can be changed only during schedule editing
(after EDIT is pressed). Fan settings in OPTIONS screen will OVER-
RIDE the scheduled fan operation.