Lennox ComfortSense 7000 series, Programming And Application Manual

Page: 1 / 28

05/09 506230−01
*2P0509* *P506230-01*
E
2009 Lennox Industries Inc.
Dallas, Texas, USA
CAUTION
This is a 24VAC low−voltage thermostat. Do not
install on voltages higher than 30VAC.
Do not short (jumper) across terminals on the gas
valve or at the system control to test installation.
This will damage the thermostat and void the war-
ranty.
IMPORTANT
In all applications, the ComfortSense
®
Model
L7742U thermostat can only be used with all resi-
dential units and approved commercial split-system
matches, and those which meet the following instal-
lation 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, con-
sult Application Note H−04−5.
These instructions are intended as a general guide and do
not supersede local codes in any way. Consult authorities
having jurisdiction before installation.
Check thermostat for shipping damage. If you find any
damage, immediately contact the last carrier.
PROGRAMMING
AND APPLICATION
GUIDE
(SERVICEMAN’S
MANUAL)
ComfortSense
®
7000 Series
CONTROLS
506230−01
05/09
Supersedes 04/09
Table of Contents
ComfortSense
®
Model L7742U Thermostat 2 . . . . . . .
Features 2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Touch Screen Display 3 . . . . . . . . . . . . . . . . . . . . . . . . . .
Home ScreenCurrent Conditions & Temp. Settings 3
Controlling the Heat/Cool Modes of Operation 4 . . . . .
Controlling the Fan Operation 5 . . . . . . . . . . . . . . . . . . .
Controlling the Schedule 5 . . . . . . . . . . . . . . . . . . . . . . .
Schedule TabProgramming 6 . . . . . . . . . . . . . . . . . . .
Options TabReminders & User Settings 8 . . . . . . . .
Options TabInstaller Settings 10 . . . . . . . . . . . . . . . . . .
Resetting Program to Factory Conditions 12 . . . . . . . . .
EPA ENERGY STAR
®
Recommended Setpoints 12 . .
Humidification 14 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Dehumidification 15 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Humiditrol
®
Enhanced Dehumidification Accy 16 . . . . .
Stage Delay and Differential Settings 17 . . . . . . . . . . . . .
Temporary Temperature Change 20 . . . . . . . . . . . . . . . .
Optional Remote Outdoor Sensor 20 . . . . . . . . . . . . . . . .
Service Reminders 21 . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Unit Part and Serial Numbers 21 . . . . . . . . . . . . . . . . . . .
Memory Protection 21 . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Appendix A. Flow Diagrams & Wiring Diagrams 22 . . .
Appendix B. Diagnostic Info./Available Sys. Settings 25
Shipping and Packing List
1 − ComfortSense
®
Model L7742U touch screen, 7−day
programmable 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
NOTE − This thermostat is equipped with automatic com-
pressor protection to prevent potential damage due to
short cycling or extended power outages. The short cycle
protection provides a 5−minute delay between heating or
cooling cycles to prevent the compressor from being dam-
aged.
Litho U.S.A.