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© 2006 LUX PRODUCTS CORPORATION. ALL RIGHTS RESERVED
Thank you for your confidence in our product. To obtain the best results from your
investment, please read these instructions and acquaint yourself with your
This thermostat can be used with most single stage 24 volt: gas, oil or electric
heating and/or cooling systems, single stage heat pumps, or gas Millivolt heating
systems. It cannot be used with 3-wire zone valves, 120 volt heating systems, or
multi-stage heat pumps. Ask your dealer for other LUX thermostats to control those
Please read ALL of these instructions carefully before beginning installation.
Save them for future reference.
• #1 Phillips screwdriver
• Drill with 3/16 in. (4.8mm) bit
• Wire Stripper / Cutter
CAUTION: This thermostat is protected against normal minor static electric
discharges, however to minimize the risk of damaging the unit in extremely dry
weather, touch a grounded metal object before touching your thermostat.
On replacement installations, mount the new thermostat in place of the old one
unless the conditions listed below suggest otherwise. On new installations, follow
the guidelines listed below.
1. Locate the thermostat on an inside wall, about 5 ft. (1.5m) above the floor, and
in a room that is used often.
2. Do not locate where air circulation is poor, such as in a corner or an alcove, or
behind an open door.
3. Do not install it where there are unusual heating conditions, such as: in direct
sunlight; near a lamp, television, radiator, register, or fireplace; near hot water
pipes in a wall; near a stove on the other side of a wall.
4. Do not locate in unusual cooling conditions, such as: on a wall separating an
unheated room; or in a draft from a stairwell, door, or window.
5. Do not locate in a damp area. This can lead to corrosion that may shorten
6. If painting or construction work has yet to be completed, cover the unit
completely or do not install it.
• Read instructions carefully before removing any wires from your existing
• Do not short (jumper) across the electric terminals on the furnace or air
conditioner to test the system. This may damage the thermostat and void your
• This thermostat should be limited to 1.5 amps per terminal, and a maximum
of 2 amps total; higher current than this may cause damage to the thermostat.
• All wiring must conform to the local codes and ordinances that are in your
• Your thermostat is a precision instrument, please handle it with care to avoid
REMOVAL OF OLD UNIT
1. Turn OFF the electricity to all heating and cooling components.
Do not turn the electricity back on until all work is completed.
2. Remove the cover and front portion of your old thermostat to
expose the wiring connections.
3. Write down the letters printed near each wire terminal that is
used, and the color of the wire that is connected to it. Using the
enclosed labels, attach a label to each of your wires so that the
letter matches the marking on your existing thermostat.
4. When they are all labeled, carefully remove the wires one at a time, making sure
that they do not fall back inside the wall. Do not allow any of the bare wire ends to
touch each other, or any parts on the thermostat.
5. Loosen all of the screws on the old thermostat and remove it from the wall.
1. Strip insulation leaving 3/8 in. (9.5mm) bare wire ends and clean off any
2. Fill wall opening with non-combustible insulation to prevent drafts from
affecting the thermostat.
Be careful not to drop the unit or disturb electronic parts. Leave the door closed
while the body is being removed from the base.
3. Remove the body from the thermostat’s base by pressing the thumb latch at the
bottom center of the unit and swinging the body away.
If you are mounting the base to soft material like plasterboard or if you are using
the old mounting holes, the screws may not hold. Drill a 3/16 in. (4.8mm) hole at
each screw, and insert the plastic anchors provided.
4. Hold the base against the wall. Route the wires through the hole below the
terminal block. Position the base for best appearance (to hide any marks from an
old thermostat). Attach the base to the wall with the two screws provided.
CONNECTING THE WIRES
5. Wires must be trapped between the black clamps and the brass
terminals as shown here.
6. Being careful not to overighten them, securely tighten all of the
electrical terminal screws, including any unused ones.
When you are finished performing your installation and setup options, please
remove the thin plastic film that is protecting the LCD display screen on the front of
the thermostat. This plastic may or may not be present, and is evident by the
appearance of fake digits appearing on the display screen.
** Complete heating and/or cooling system wiring can be found in the WIRE
IDENTIFICATION AND WIRING SCHMATICS section of this instruction sheet. The
schmatics shown provide component information for brand new installations or
for unreferenced wires.
Install two new Energizer
size alkaline batteries before continuing further.
Ensure that the batteries are installed in the
proper direction as per the markings shown in
the battery tray.
All of the settings, options, and components listed in this section are located on the
rear of the thermostat, on the circuit board.
The hardware reset is a push button that is located on the right edge of the circuit
board, just above the battery location. This reset button is used by the thermostat
to reset the unit’s clock, and read the position of all of the option switches. When
any of the following items are changed, the hardware reset button must be pushed
for the change to be recognized. User temperature programs are not erased when a
hardware reset is performed.
This is a plastic jumper cap which
can be in one of two positions,
GAS or ELECTRIC.
The Furnace Mode setting determines how the thermostat controls the fan
operation. This setting has no effect in Cool Mode. While in Heat Mode, with the
jumper in the Gas position, the fan is controlled by your furnace. With the jumper
in the Electric position, the fan is controlled by the thermostat and is turned on
when the heating terminal becomes energized.
The following option settings are all located within a group of small switches
labeled 1 through 3 as shown below, and are located in the center of the circuit
This determines how the thermostat displays the clock and all other times on the
screen. Switch position OFF is 12 HR, and ON is 24 HR.
This determines how the thermostat displays all temperatures on the screen.
Switch position OFF is F°, and ON is C°.
This determines how the remaining filter life will be displayed when the rotary dial
is turned to the AIR FILTER position. In the Percent (%) mode, the display will
count down the percentage of air filter life remaining before a filter change is
recommended. In the Days mode, the display will count down the number of
calendar days remaining before a filter change is recommended. Switch position
OFF is Percent mode, and ON is Days mode.
The software reset is a small recessed push button that is located right above the
NEXT button. This button can be pushed with a pencil or the end of a paper clip.
This reset clears all of the heating and cooling programs, filter settings, and other
user changeable preferences to their default values. You should write down your
heating and cooling program times and temperatures prior to using the software
There are two mode switches on the front, a Temperature mode switch and a Fan
mode switch. The Temperature mode switch has three positions: HEAT, OFF, and
COOL. In the winter, set the system switch to HEAT to control your heating system.
In the summer, set the switch to COOL to control your air conditioner. In the spring
and fall or when the windows are open, you can set the switch OFF. The Fan mode
switch has two positions, AUTO and ON. Setting the Fan mode switch to AUTO,
automatically runs your system's blower fan as required only during heating and
cooling activation. Setting the Fan mode switch to ON, runs your system’s fan
continuously, even if heating or cooling is not needed, including when the
Temperature mode switch is in the OFF position to provide air circulation only.
The Fan mode switch only works if your system provides a wire for the
thermostat’s “G” wire terminal.
There are four primary push buttons on the front of the thermostat: The UP and
DOWN arrow keys, the NEXT button, and the HOLD button.
The LUX Speed Dial
provides an easy way to quickly navigate between the different
programming areas. This rotary dial has five individual positions.
Rotate the dial to the SET DAY/TIME position. You should see the word SET appear
on the display, along with the clock and a day of the week that is flashing. With the
day flashing, press the UP button to advance the day to the desired day. Press the
NEXT button, this should cause the time to start flashing and the day to remain on
steady. Using either the UP or DOWN buttons, adjust the clock to the desired time.
The clock digits will increment rapidly if either the UP or DOWN buttons are held in
the pressed position.
HEATING AND COOLING
Basic operation of your heating or cooling system can be obtained by ensuring that
the rotary dial is in the RUN position, and simply moving the Temperature mode
switch to either the HEAT or COOL position. Prior to being set initially with your
custom temperature program, and also after a Software Reset, the thermostat will
follow the default Energy Star
approved temperature routines that are preset within
the thermostat’s memory, as shown below.
MINIMUM RUN TIME DELAY
This is determined by the thermostat, and controls the minimum length of time that
the thermostat must remain with Heat or Cool either On or Off, before it will
automatically switch to the alternate On or Off state. This feature prevents rapid or
short cycling, and provides compressor protection for cooling equipment. The time
amount for this delay is fixed at 5 minutes between on or off load changes.
A Temperature Override occurs in Run mode, in either Heat or Cool, anytime the
user adjusts the set temperature to a value that differs from the stored program
temperature for that day and time. When the thermostat is in an Override, the word
Override will appear in the temperature area of the display. The thermostat will
maintain thermal control using this new set temperature, until the start of the next
program period time is reached. At the start of the next program period, the set
temperature will return to its programmed value. To enter an Override in either Heat
or Cool mode, push either the UP or DOWN button once and the set temperature
will begin to flash. Push either the UP or DOWN button to the new desired set
temperature value. An Override may be cancelled by rotating the dial, changing the
Temperature mode switch, or by initiating a Temperature Hold.
A Temperature Hold is similar to an override, but is used for maintaining a constant
set temperature for a longer time duration. Once a Hold is initiated, the thermostat
will maintain the Hold set temperature indefinitely. A temperature hold may be used
for days, weeks, or even months at a time. To enter a Hold, push the HOLD button
once, and the word Hold will appear in the temperature portion of the screen, along
with the set temperature flashing. While the set temperature is flashing, push either
the UP or DOWN button to the new desired set temperature value. To cancel a Hold,
press and release the HOLD button once again, rotate the dial, or change the
Temperature mode switch.
AIR FILTER MONITOR
The Air Filter Monitor counts the number of days, and the amount of usage since
your filter has been replaced. In Run mode, the CHANGE FILTER indicator will
appear when the remaining filter days have reached zero and the filter should be
changed. To set and use the Air Filter Monitor, turn the rotary dial to AIR FILTER.
Press NEXT and the Filter Days Left value will start flashing. Use the UP or DOWN
buttons to select the number of days of filter life that your filter is rated for. Setting
this value to OFF will disable the filter monitor. Return the dial to the RUN position
once you are finished setting the filter life. To monitor the Filter Days Left or Filter
Percent Left, turn the dial to the AIR FILTER position. The amount of filter life
remaining will be shown in the clock portion of the display screen. Return the dial
to the RUN position once you are finished viewing the filter life remaining.
RESET FILTER COUNTER
Once you have replaced your filter, the filter life counter is reset back to its full
amount remaining value by turning the dial to AIR FILTER and pressing the UP and
DOWN buttons together at the same time. NOTE: The counter is also reset by
changing the filter setting value, as described above, to a different number of days.
A thermostat works by turning your heating or cooling system on and off whenever
the room temperature varies from the set-point temperature. The amount of this
variation is called the “swing.” Your system should cycle on about 3 to 6 times per
hour. A smaller swing number increases the number of cycles per hour, so the
room temperature is more precise and constant. A larger swing number decreases
the number of cycles per hour, but saves energy in most cases. To change the
Swing setting, turn the dial to RUN mode. Hold down the NEXT button and push the
HOLD button once, then let go of both. The words SWING and SET will appear on
the screen with a number. Use the UP/DOWN buttons to change the number value
between 1 and 9. Number 1 is the default setting. Press the NEXT button to accept
the setting and return to normal Run mode.
The internal temperature sensor in this thermostat is accurately calibrated at the
factory. The Temperature Calibration feature allows you to manually offset the
measured temperature by as much as plus or minus 5°F (3°C) degrees from its
original value. This feature can be useful to match this thermostat to another one
or more, if multiple thermostats are used in the same home. To change the
Temperature Calibration, turn the dial to RUN mode, and place the Temperature
mode switch in the OFF position. Hold down the UP button and push the DOWN
button once, then let go of both. The words CAL and SET will appear on the screen
with a number. Use the UP/DOWN buttons to change the number value between -
5°F (-3°C) and +5°F (+3°C) degrees. 0 degrees of correction is the default setting.
Press the NEXT button to accept the setting and return to Run mode.
To prevent tampering with any of your settings or temperatures, most of the front
panel buttons can be locked out by pressing the following four-button sequence:
NEXT, NEXT, NEXT, HOLD. This sequence of keys will lock and also unlock these
items: UP, DOWN, NEXT, HOLD, the Rotary Dial, and the Software Reset button.
Neither of the Mode slide switches are locked out. When the Keylock is activated, a
padlock icon will be visible in the area above the clock as shown below.
The Keylock will be disabled if the Hardware Reset button is pressed.
For all of the programming areas that are described below, this thermostat provides
four independent periods per day for Heat mode and Cool mode, they are: MORN,
DAY, EVE, and NITE. Each period ends at the start time of the following period. The
programs for each Temperature mode are programmed separately. When you
perform a Software Reset, an Energy Star
approved program is inserted into all of
the program periods. You can use these default programs or alter any portion of
them to suit your own preferences. When setting the program items, the value that
is flashing is the item that you can change at that time.
SET WEEKDAY PROGRAM
Select either HEAT or COOL with the Temperature mode switch. Rotate the dial to
WEEKDAY PROGRAM. You will be programming all five weekdays at the same time.
The first period is MORN. Using the UP and DOWN buttons, set the start time for
this period, and then push the NEXT button to proceed. Now set the desired set
temperature for the MORN period using the UP and DOWN buttons, and push NEXT
to proceed. Now set the start time and set temperature for the DAY period,
pushing NEXT after each to advance. Continue with these same steps to set the
start time and set temperature for the EVE, and NITE program periods. When you
are finished setting all four periods, you may continue pushing the NEXT button
through all four periods to review your entries, or turn the dial to RUN if you are
finished. These same programming steps for all four periods must be performed in
both Heat and Cool Temperature modes independently.
SET WEEKEND PROGRAM
Turn the dial to WEEKEND PROGRAM. You will be programming both Saturday and
Sunday at the same time. You will begin with the start time of the MORN period,
and use the same procedures that were performed while setting the Weekday
Program periods, using the NEXT button to advance through the values. Return the
dial to the RUN position when you are finished.
This thermostat can be powered either by “AA” alkaline batteries, by 24VAC system
common power, or a combination of both. If you are using batteries alone, the
batteries should be replaced AT LEAST once per year, or sooner if the LOW BAT
battery symbol appears in the lower left
portion of the display screen as shown
To replace the batteries in the thermostat,
remove the thermostat’s body from the
base plate attached to the wall by pressing the thumb latch at the bottom center of
the unit and swinging the body towards you, up and away from the base. Remove
the used batteries from the battery tray and discard appropriately.
Install two new Energizer
, “AA” size alkaline batteries into the
battery tray. Observe the polarity markings shown in the battery compartment to
ensure proper installation. When finished, hang the top of the unit by the tabs at
the top corners of the base, then snap the bottom of the unit into place. Do not use
unnecessary force. If the body does not snap into place easily, remove the body, re-
hang it from the tabs and try again.
If you have any problems installing or using this thermostat, please carefully and
thoroughly review the instruction manual. If you require assistance, please contact
our Technical Assistance department at 856-234-8803 during regular business
hours between 8:00AM and 4:30PM Eastern Standard Time, Monday through
Friday. You can also receive technical assistance online anytime day or night at
http://www.luxproducts.com. Our web site offers you answers to the most common
technical questions, and also permits you to email your questions to our technical
support staff at your convenience.
Limited Warranty: If this unit fails because of defects in materials or workmanship
within three years of the date of original purchase, LUX Products Corporation will,
at its option, repair or replace it. This warranty does not cover damage by accident,
misuse, or failure to follow installation instructions. Implied warranties are limited
in duration to three years from date of original purchase. Some states do not allow
limitations on how long an implied warranty lasts, so the above limitation may not
apply to you. Please return malfunctioning or defective units to the participating
retailer from which purchase was made, along with proof of purchase. Please refer
to the “TECHNICAL ASSISTANCE” section before returning thermostat. Purchaser
assumes all risks and liability for incidental and consequential damage resulting
from installation and use of this unit. Some states do not allow the exclusion of
incidental or consequential damages, so the above exclusion may not apply to you.
This warranty gives you specific legal rights and you may also have other rights
which vary from state to state. Applicable in the U.S.A. only.
TX500E Programmable Thermostat
Set Temperature Buttons
LCD - Liquid Crystal Display
6:00 AM 70 °F (21 °C)
8:00 AM 62 °F (17 °C)
6:00 PM 70 °F (21 °C)
10:00 PM 62 °F (17 °C)
6:00 AM 78 °F (26 °C)
8:00 AM 85 °F (29 °C)
6:00 PM 78 °F (26 °C)
10:00 PM 82 °F (28 °C)
WARNING: Use Energizer
Alkaline Batteries Only.
is a registered trademark of Eveready Battery Company, Inc.
is a registered trademark of The Gillette Company, Inc.
Mt. Laurel, New Jersey 08054, USA
FRONT PANEL ITEMS
BATTERIES AND MAINTENANCE
• Small elegant design
• Exclusive LUX Speed Dial
• Air Filter Monitor
• 5-2 Day Programming
• Energy Star Compliant
• 4 Periods Per Day
• Battery Free Memory Storage
• Temporary Temperature Override
• Temperature Hold
• Keyboard Lockout
• F/C Temperature Display
• 12/24 Hr Clock Display
• Adjustable Temperature Differential /
• User Temperature Offset /
• 5 Minute Minimum Run/Off Time For
Short Cycle and Compressor