Date Code & Serial Number; Features - Lennox SignatureS
tat 81M26 Programming And Application Manual

S
81M27 − 2 stage heat / 2 stage cool, conventional
S
81M28 − 2 stage heat / 2 stage cool, heat pump (Provides 2 stages of
heat pump cooling and one stage of heat pump heating. A second−
stage of auxiliary backup heat is also provided.)
S
46M98 − Outdoor temperature sensor (included with thermostat)
These instructions are intended as a general guide and do not supersede
local codes in any way. Consult authorities having jurisdiction before instal-
lation.
Check equipment for shipping damage. If you find any damage, immediate-
ly contact the last carrier.
Date Code & Serial Number
The date code and serial number are on the back of the SignatureStatt
thermostat (shown in figure 1). Date code identifies when the thermostat
was manufactured; serial number uniquely identifies each thermostat for
tracking purposes.
Figure 1. Date Code and Serial Number
SERIAL
DATE
NUMBER
CODE
(02634)
(0411)
(BACK OF
SignatureStat t
THERMOSTAT)

Features

Outdoor Temperature Sensor
The outdoor sensor is provided as a standard component of each Signatu-
reStatt thermostat. In addition to measuring and displaying outdoor tem-
perature, the outdoor sensor provides dew point adjustment and control for
all models. It can also be used with the multistage heat pump thermostat
(81M28) to provide optimal heating equipment operation via programmable
balance points.
NOTE − Outdoor sensor must use twisted pair wiring (Lennox Cat, No.
84X49 [1000'] or X3790 [500']).
When an outdoor sensor is connected,
the temperature is displayed on the
LCD at the right hand side. For exam-
ple, the display will show OUTSIDE
90" if the outdoor temperature is mea-
sured to be 90°F.
NOTE − For proper operation of Humiditrol
sor MUST be installed.
L" Input
"L" input from the equipment is used to notify the user if the equipment fails.
The "L" terminal is connected to common through a resistor, LED, and volt-
age regulator. The CHECK LED is illuminated when 24 VAC is applied to
the L terminal. Nothing is displayed on the user interface screen.
Compressor Short Cycle Protection
A 5−minute compressor short cycle protection timer begins when a com-
pressor output is de−energized.
Page 3
MONDAY 3:29 PM
AUTO
ºF
78
FAN AUTO
SET AT 78
OUTSIDE 90
27%RH
HOLD TEMP MENU
®
applications, the outdoor sen-
SignatureStat t Thermostat