Lennox ComfortSense L7742U User Manual

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 L7742U Thermostat

Touch Screen Display

Home Screen—Current Conditions & Temperature Settings

Controlling Heat/Cool Modes of Operation

Schedule tab—Programming

Options tab—Reminders/User 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)