Lennox ComfortSense L7742U

05/09 506228−01
*2P0509* *P506228-01*
E2009 Lennox Industries Inc.
Dallas, Texas, USA
Shipping and Packing List
1 − ComfortSense
®
Model L7742U touch screen, 7−day program-
mable thermostat
2 − Mounting screws (M3.5x25mm self−tapping screws)
2 − Wall Anchors
1 each − Installation Quick-Start Guide, Programming & Application
Guide, Homeowner’s Manual, Warranty card, Warranty Audit tag
PROGRAMMING AND
APPLICATION GUIDE
ComfortSense
®
7000 Series
Model L7742U Touch Screen Programmable Thermostat
CONTROLS
506228−01
05/09
Supersedes 04/09
IMPORTANT
Read this manual before programming the thermostat.
Use this thermostat only as described in this manual.
IMPORTANT
In all applications, the ComfortSense
®
Model L7742U thermo-
stat can only be used with all residential units and approved
commercial split-system matches, and those which meet the
following installation criteria:
S installation uses 18 GAUGE thermostat wire or larger,
S thermostat wire run length DOES NOT EXCEED 300’ (91m),
S load from any thermostat connection is 1 AMP or LESS.
If used with Harmony II
®
Zone Control System, consult Applica-
tion Note H−04−5.
Litho U.S.A.

Lennox ComfortSense L7742U Specifications

General

Brand	Lennox
Model	ComfortSense L7742U
Category	Thermostat
Language	English

Summary

ComfortSense Model L7742 U Thermostat

Touch Screen Display

Home Screen-Current Conditions & Temperature Settings

Controlling HeatCool Modes of Operation

Schedule tab-Programming

Options tab-RemindersUser Settings

Reminders

Setting and managing service reminders for filter changes, system checks, and maintenance.

User Settings

Configuration options for time format, display, fan settings, and security.

Options tab-Installer Settings

SYSTEM SETUP

Configuring the thermostat for specific HVAC system types, stages, and backup heat.

Humidification

Dehumidification

INSTALLER SETTINGS

Stage Delay & Differential Settings (Installer settings)

Temporary Temperature Change (Pausing the Schedule)