Lennox ComfortSense L5732U User manual

E2007 Lennox Industries Inc.
Dallas, Texas, USA
ComfortSenset5000 Series Model No. L5732U
3 Heat / 2 Cool Programmable
Touch Screen Thermostat
INSTALLATION
INSTRUCTIONS
WARNING
This thermostat is to be installed by a qualified service technician or
other qualified agency in accordance with the manufacturer’s instruc-
tions, all codes, and requirements of the authority having jurisdiction.
506068−01
2/2008

Page 2
Table of Contents
General Page 2. . . . . . . . . . . . . . . . .
Shipping and Packing List Page 2.
NecessaryTools Page 2. . . . . . . . . .
Thermostat Location Page 2. . . . . .
Remove Existing Thermostat Page 3
Thermostat Installation Page 4. . . .
Wiring Connections Page 4. . . . . . .
LED Indicator Page 5. . . . . . . . . . . .
Outdoor Temp. Sensor Page 5. . . .
Field Wiring Diagrams Page 6. . . .
Install Batteries Page 8. . . . . . . . . .
Attach T’stat to Wallplate Page 8. .
Set Calendar and Clock Page 8. . .
Adv. Heat Pump Features Page 9.
Installer Set−Up Page 11. . . . . . . . . .
System Test Page 19. . . . . . . . . . . . .
Troubleshooting Page 20. . . . . . . . . .
General
The Lennox ComfortSenset5000
Series L5732U programmable touch
screen thermostat provides control for
up to three stages of heating and two
stages of cooling. The thermostat may
be used to control either a convention-
al HVAC system which includes an out-
door condensing unit and indoor fur-
nace or a heat pump unit and indoor air
handler. The thermostat terminal block
accommodates 24V power common
from the furnace or air handler. Three
AAA alkaline batteries are provided to
be used as an alternate power source
or as a back−up in case of an interrup-
tion of power.
Shipping and Packing List
Package 1 of 1 contains
1 − Assembled thermostat (includes
wallplate and thermostat)
1− Bag assembly containing the fol-
lowing:
2 − Screws
2 − Wall anchors
3 − AAA alkaline batteries
1 − Installation instruction
1 − Owner’s guide
1 − Warranty certificate
Necessary Tools
SNo. 2 Phillips screwdriver
SStandard pocket screwdriver
SDrill
SDrill bits (use 3/16" for drywall and
7/32" for plaster)
SPencil
SLevel
SHammer
SElectrical tape
Thermostat Location
Install the thermostat about 5 feet
(1.5m) above the floor in an area with
good air circulation.
Do not install the thermostat where it
may be affected by the following:
SDrafts or dead spots behind doors
and in corners.
SHot or cold air from ducts.
SRadiant heat from the sun or ap-
pliances.
SConcealed pipes or chimneys.
SAdjacent unconditioned areas
(outside wall behind the thermo-
stat).

Page 3
Remove Existing Thermostat
If this thermostat is being used to re-
place an existing thermostat, remove
the old thermostat:
1 − Turn off power at the heating and/
or cooling system or fuse/circuit
breaker panel.
2 − Remove the cover from the exist-
ing thermostat.
3 − Remove securing screws and re-
move existing thermostat from
wall or wallplate. Disconnect and
label the existing wires.
4 − Remove any remaining portion of
the existing thermostat from the
wall. Do not install the replace-
ment thermostat faceplate on the
existing wallplate. Though the
wallplates may appear to be the
same and the faceplate may fit on
the existing wallplate, the terminal
positions may vary in important
ways. In addition, serial number
and part number information is
carried on the replacement wall-
plate.
Do not allow the thermostat wires
to fall behind the drywall.
WARNING
This thermostat must be
installed using the provided re-
placement wallplate.
Failure to do so will bypass ther-
mostat control and activate con-
tinuous heating.
Y
G
C
R
W
OLD THERMOSTAT
.18
.2
.25 .3
.9
.7
.5
.4
L
O
NGER
THERMOSTAT
COVER
WALLPLATE
WARNING
MERCURY NOTICE
If the existing thermostat includes a mercury bulb, the thermostat must
be disposed of properly.
Contact your local waste management authority for instructions re-
garding recycling and proper disposal of thermostats which include
mercury bulbs.

Page 4
Thermostat Installation
The thermostat may be installed hori-
zontally in a 4 in. X 2 in. (101.6 mm X
50.8 mm) wiring box or on the wall us-
ing the provided anchors.
1 − Separate the wallplate from the
thermostat as shown.
THERMOSTAT
WALLPLATE
WIRE HOLE
2 − Pass the labeled wires through the
hole on the wallplate.
3 − Position the wallplate on the wall
with the arrow pointing up. Level
the wallplate (for appearance
only) and use a pencil to mark the
mounting holes.
WALLPLATE
LEVEL
PLACE LEVEL ON
SUPPORT TABS
MARK
MOUNTING
HOLES (2)
4 − If anchors are used, move the
wallplate aside and drill two new
holes (3/16" for drywall; 7/32" for
plaster).
5 − Tap the provided wall anchors into
the drilled holes until the back of
the anchor head touches the wall
surface.
6 − Position the wallplate over the an-
chors and pull the thermostat
wires back through the wiring
opening.
7 − Secure the wallplate using the
provided screws.
DRILLED
HOLES (2)
WALL
ANCHORS (2)
MOUNTING
SCREWS (2)
WALLPLATE
NOTE
Thermostat heat function will
not operate if thermostat has
been stored at, or is being used
in, ambient temperatures at or
above 90°F. Heat function will be
enabled after thermostat has
been placed in ambient tempera-
tures less than 90°F for about 30
minutes.
Wiring Connections
WARNING
Use minimum 18 guage wire for
all thermostat connections.
IMPORTANT
Do not connect the wires to this
thermostat based on wire color.
Improper wiring may cause
damage to the HVAC system.

Page 5
1 − Make wiring connections per the
appropriate wiring diagram on
page 6 or 7. Refer to the table
below for terminal designations.
Terminal Description
Y2 Second−stage cooling
W2 (AUX) Second−stage heating
(or auxiliary heating)
W (E) First−stage heating
(or emergency heating)
S1 Remote outdoor sensor
S2 Remote outdoor sensor
R24V power
OReversing valve
BReversing valve
GFan relay
YFirst−stage cooling
C24V common
LEquipment monitor
2 − Refer to inner terminal labels
when using the thermostat with
conventional systems (gas, oil or
electric heat plus air conditioning).
Refer to outer terminal labels in
heat pump applications. See fig-
ure below.
3 − Loosen screws of terminals that
will be used. Insert appropriate
wires in the terminal block under
the loosened screws. Securely
tighten each screw.
C
Y
B
O
R
G
INSERT WIRE IN HOLE
WIRE HOLE
WALLPLATE
SCREW
TERMINALS
LETTER
DESIGNATIONS
LABELED WIRES
TERMINAL
BLOCK
4 − Connect wires to the correspond-
ing screw terminals per the ap-
propriate diagram.
5 − Push excess wire back into the
wall.
6 − Plug hole with nonflammable in-
sulation to prevent drafts from af-
fecting thermostat.
LED Indicator
An LED indicator is located in the up-
per right corner of the thermostat. It is
only visible when lit.
When an equipment monitor is con-
nected to the thermostat L terminal,
the LED lights when the monitor sends
a check or failure message to the ther-
mostat.
The LED requires the use of 24Vac
common power. The indicator will not
light when the thermostat is powered
by the batteries alone, or when 24Vac
power is interrupted.
Outdoor Temperature Sensor
Install the optional outdoor tempera-
ture sensor (X4148) as outlined in the
instructions provided with the sensor.

Page 6
Field Wiring Diagrams
TYPICAL CONVENTIONAL MULTI−STAGE APPLICATION
TWO−STAGE HEAT / TWO−STAGE COOL
TYPICAL MULTI−STAGE HEAT PUMP APPLICATION
NO AUXILIARY HEAT
TYPICAL MULTI−STAGE HEAT PUMP APPLICATION
WITH AUXILIARY HEAT

Page 7
Field Wiring Diagrams (Continued)
TYPICAL SINGLE−STAGE HEAT PUMP SYSTEM WITH AUXILIARY HEAT
TYPICAL SINGLE−STAGE HEAT PUMP SYSTEM WITHOUT AUXILIARY HEAT

Page 8
Install Batteries
1 − Install three provided AAA alkaline
batteries in the back of the thermo-
stat as shown.
BACK OF THERMOSTAT
BATTERIES
(3)
+
++
2 − Remove tab from the lower right−
hand corner of the thermostat
back to activate the real−time
clock.
REMOVE DURING
INSTALLATION
REMOVE
TAB
REMOVE DURING
INSTALLATION
Attach Thermostat to Wallplate
NOTE − The thermostat may be pro-
grammed before it is secured to the
wallplate.
1 − Align the terminal blocks on the
wallplate with the pins on the back
of thermostat.
2 − Push the thermostat straight onto
the pins until it snaps into place.
3 − Turn on power at the furnace or air
handler or at the fuse or circuit
breaker.
PINS ON
BACK OF
THERMOSTAT
WALLPLATE
TERMINAL
SCREW
BLOCK
Set Calendar and Clock
This thermostat is designed to auto-
matically keep the current time and
date in memory for up to ten years, un-
der normal use, once the calendar has
been set. When power is first applied to
the thermostat, the display is ready to
set the calendar.
1 − Use the arrow keys to set the year,
month and day.
2 − Press the DONE key.
DONE
USE
ARROWS
TO SET
YEAR
SET
CURRENT
DATE
SET
MONTH
MON WED THU FRI SATTUE
3 − Use the arrow keys to set the cur-
rent time.
4 − Press the DONE key.
DONE
MON WED THU FRI SAT
AM
PM
USE
ARROWS
TO SET
TIME
TUE
NOTE − Date and time may be ad-
justed after the initial set−up using ei-
ther the installer or user set−up menu.

Page 9
Advanced Heat Pump Features
The thermostat installer set−up may be
configured in several different ways to
ensure the desired system operation.
Heat Pump Application
Dual Fuel (Fossil Fuel) Aux. Heat
Outdoor Temperature Sensor and
Thermostat Control Aux. Heat
(No external dual fuel kit)
Installer set−up as follows:
SInstaller set−up number 0170 −−
option 7, 11, or 12 −− heat pump.
SInstaller set−up number 0200 −−
option 1 −− back−up heat is fossil
fuel.
SInstaller set−up number 0210 −−
option 0 −− no external fossil fuel
kit.
SInstaller set−up number 0340 −− not
shown −− outdoor temperature
sensor for control option chosen
by default.
SInstaller set−up number 0350 −−
choose appropriate balance point
temperature.
Heating Mode Operation
Outdoor Temp. above Balance
Point
When the outdoor temperature is
above the selected balance point, the
compressor satisfies the heating de-
mand. However, if the room thermostat
senses an indoor temperatature drop
of 2°F or more while the compressor is
operating, the heat pump operation will
stop and the furnace will satisfy the re-
maining heating demand.
NOTE − The balance point setting is
selected using Installer Set−Up Num-
ber 0350.
Heating Mode Operation
Outdoor Temp. below Balance Point
When the outdoor temperature is be-
low the selected balance point, only
the furnace (fossil fuel) operates to sat-
isfy the heating demand. The fan (G
terminal) does not energize when the
thermostat calls for heat.
Emergency Heat Operation
When the emergency heat mode of op-
eration is selected by the thermostat,
compressor operation is locked out.
The first stage of heat becomes what is
connected to the thermostat E termi-
nal. The second stage of heat be-
comes what is connected to the Aux.
terminal. In cases where there is only
one source of non−compressor heat,
the E terminal must be jumped to the
Aux. terminal.
Heat Pump Application
Dual Fuel (Fossil Fuel) Aux. Heat
Using External Dual Fuel Kit
Installer set−up as follows:
SInstaller set−up number 0170 −−
option 7, 11, or 12 −− heat pump.
SInstaller set−up number 0200 −−
option 1 −− back−up heat is fossil
fuel.
SInstaller set−up number 0210 −−
option 1 −− external fossil fuel kit is
controlling heat pump auxiliary
heat.
SInstaller set−up number 0340 −−
option 0 or 1 −− outdoor tempera-
ture sensor not used or used for
display only.
SInstaller set−up number 0350 −−
choose appropriate balance point
temperature.
Heat pump operation is determined by
external fossil fuel kit.

Page 10
Heat Pump Application
Electric Auxiliary Heat
with Outdoor Temperature Sensor
SInstaller set−up number 0170 −−
heat pump.
SInstaller set−up number 0200 −−
back−up heat is electric.
SInstaller set−up number 0340 −−
outdoor temperature sensor for
control option chosen.
SInstaller set−up number 0350 −−
choose appropriate compressor
lock−out temperature.
SInstaller set−up number 0360 −−
choose appropriate auxiliary lock−
out temperature.
NOTE − There is a minimum 5°F dead-
band between the compressor and
auxiliary heat lock−out temperatures.
Heating Mode Operation
When the outdoor temperature is be-
low the compressor lock−out tempera-
ture (balance point), only the auxiliary
heat operates.
When the outdoor temperature is
above the auxiliary lock−out tempera-
ture (balance point), only the compres-
sor operates.
When the outdoor temperature is be-
tween the two temperatures, both the
compressor and auxiliary heat oper-
ate.
COMPRESSOR
LOCK−OUT
TEMPERATURE
AUXILIARY
LOCK−OUT
TEMPERATURE
COMPRESSOR ONLY
BOTH COMPRESSOR AND
AUXILIARY HEAT
AUXILIARY ONLY
50
35
OUTDOOR TEMPERATURE
Emergency Heat Operation
When the thermostat is set for the
emergency heat mode, the compres-
sor and auxiliary lock−out features are
turned off. Compressor operation is
locked out. The first stage of heat be-
comes what is connected to the ther-
mostat E terminal. The second stage of
heat becomes what is connected to the
Aux. terminal.