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E2007 Lennox Industries Inc.
Dallas, Texas, USA
RETAIN THESE INSTRUCTIONS
FOR FUTURE REFERENCE
51M34 5/2 Day Programmable Thermostat
The Lennox 51M34 5/2 day programmable electronic
thermostat has a large, easy-to-read display and provides
excellent temperature control. This product includes a
programmable filter change reminder, an equipment
maintenance reminder, and a system check indicator to
notify the user when the equipment requires service.
The 51M34 thermostat is suitable for non−heat pump,
single-stage heat/single-stage cool applications with either
gas or electric furnace.
General
These instructions are intended as a general guide and do
not supersede local codes in any way. Consult authorities
having jurisdiction before installation.
Check equipment for shipping damage. If you find any
damage, immediately contact the last carrier.
Introduction
This document describes the operation of Lennox 51M34
thermostat . Refer to the installation manual for instructions
regarding installation and wiring of the thermostat.
Initial Thermostat Power-up
When power is initially applied to the thermostat, the dis-
play will appear as shown in figure 1.
08/07
*2P0807*
OPERATION
MANUAL
51M34 5/2 Day
Programmable Thermostat
CONTROLS
505,048M
08/07
Supersedes 05/05
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MO TU WE TH FR SA SU
I8:88
AM
PM
PROG
A | B | C | D
ROOM
88
SETPOINT
°
88
Figure 1. Initial Power−Up Display
All display segments are momentarily activated. This oc-
curs as a normal part of thermostat initialization. Within a
few seconds, the Home Screen appears (see figure 2) with
default settings as shown. After about 1 minute of initializa-
tion time, the actual room temperature will be displayed.
Litho U.S.A.
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MAINT
FILTER
SERVICE
FAN
HOLD
ON
AUTO
SYSTEM
COOL
°
OFF
EMG.
Hi
Lo
HEAT
505,048M
*P505048M*
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Table of Contents
Related Manuals for Lennox 51M34 5/2
Summary of Contents for Lennox 51M34 5/2
-
Page 1: Table Of Contents
......The Lennox 51M34 5/2 day programmable electronic HOLD − Temperature Hold Mode . -
Page 2: Buttons, Backlight, Timers & Settings
MAINT TU WE TH FR SA SU I2:00 FILTER Heat Cool SERVICE Prog Day/Time PROG A B C D HOLD AUTO Hold (DOOR ROOM SYSTEM OPEN) Settings Enter ° COOL HEAT Figure 3. Thermostat Buttons Figure 2. Home Screen When an Arrow, HOLD, HEAT, or COOL button is pressed, At this point, the thermostat will be fully functional;... -
Page 3: Heat − Heat Mode
NOTE − Heating equipment is activated for at least 3 min- snowflakes will flash; however, the cooling equipment will utes if no buttons are pressed during the demand interval. not operate until the 5−minute delay has elapsed. Page 3 51M34 5/2 DAY PROGRAMMABLE THERMOSTAT... -
Page 4: Hold − Temperature Hold Mode
HOLD − Using Temperature Hold Modes PROG − Thermostat Programming The 51M34 thermostat can be programmed to perform a When HOLD is displayed at the HOME screen, the ther- set of either heating or cooling events (but not a mostat is in a temperature hold condition. This means that combination of heat and cool) for 5 consecutive days using the temperature program data is ignored and the thermo- a set of 4 unique events per day. -
Page 5: Fan − Controlling Fan Operation
14) once or twice for the desired reminder as shown in fig- screen will blink for a few moments to indicate that the tim- ure 15 and as described in table 1. er has been reset. Page 5 51M34 5/2 DAY PROGRAMMABLE THERMOSTAT... -
Page 6: Service Indicator
Service Indicator Removing/Installing Thermostat When abnormal equipment operation is detected, the The thermostat hinges on tabs on the top of the subbase; SERVICE indicator will flash on the screen (see figure 17). no tool is needed to remove the thermostat from the sub- This indicates that the equipment requires service from a base. -
Page 7: Technical Specifications
Settings of Off, 1, 3, 6 or 12 (months of fan run time) are every 15 seconds. Displayed temperature is the average available. When programmed time has elapsed, a FILTER of the last four measurements. indicator is displayed. Page 7 51M34 5/2 DAY PROGRAMMABLE THERMOSTAT... -
Page 8: Thermostat Output Table
Maintenance Reminder Thermostat Operating Conditions Settings of Off, 6 or 12 (months of chronological time) are 35°F to 105°F, 5% to 90% RH available. When programmed time has elapsed, a mainte- nance indicator MAINT" is displayed. Thermostat Storage Conditions Service Reminder −40°F to 185°F, 5% to 95% RH The SERVICE indicator is displayed only under the follow- ing conditions:...
Need help?
Do you have a question about the 51M34 5/2 and is the answer not in the manual?
Questions and answers
Backlight doesn’t illuminate
The backlight on the Lennox 51M34 5/2 thermostat activates for 30 seconds when any button is pressed. If the backlight is not illuminating, possible reasons include:
1. No button has been pressed.
2. A power loss may have occurred, affecting the thermostat's function.
3. An electrical issue or malfunction in the thermostat.
If none of these apply, checking the power supply and thermostat settings may help resolve the issue.
This answer is automatically generated
My back light does not light up
The backlight on the Lennox part number 51M34 5/2 only activates for 30 seconds when any button is pressed. If no buttons are pressed, or if there is no 24VAC power to the thermostat, the backlight will not light up. Additionally, temporary backlight activation may occur during electrical disturbances, but this is normal and stops once the disturbance ends.
This answer is automatically generated