Controlling The Fan Operation - Lennox ComfortSense L7742U Programming Manual

Controlling the Fan Operation

Press the screen anywhere − the first press turns on the
backlight.
From the HOME screen press FAN field; repeated
presses scroll through all the modes, AUTO, ON,
and CIRC (circulate).
Fan Modes
Fan Modes (ON, AUTO and CIRC) can be changed either
from HOME screen or from the SCHEDULE screen when
programming the thermostat. The three settings work like
this:
S
If FAN mode displays AUTO on the HOME screen, this
means that FAN is following the schedule.
S
If FAN mode displays ON on the HOME screen, this
means that the fan is NOT following the schedule and
that the fan will run continuously until it is changed
from the HOME screen.
S
If FAN mode displays CIRC on the HOME screen, this
means that the fan is NOT following the schedule and
that the fan will cycle during periods of equipment inac-
tivity. The cycle time is dependant on user settings
FAN CIRCULATE (Page 7).
If FAN mode displays AUTO (HOME) and ON or CIRC was
selected during scheduling for the current period, the ther-
mostat 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 7]):
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 7). If set to AUTO, the fan will
come on with the equipment to serve the heating/cooling
demand and go off accordingly. Using the fan continuously
or circulating the fan during the occupied times may better
improve the indoor air quality.
NOTE − When the HOME 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 7). When FAN − AUTO is selected in
the HOME screen, the schedule IS followed.
Controlling the Schedule
Press the screen anywhere − the first press turns 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 6). If OFF, the system operates as a
non−programmable thermostat the user must
make changes
autochangeover feature will continue to operate
based on the manual user inputs.
Page 5
when desired.
ComfortSenset Model L7742U Touch Screen
7−Day Programmable Thermostat
The