INSTALLATION & OPERATION
MANUAL
Model TME-____________________*
* Balance of model number is determined by
customer specied limits and Setbacks.
AUTOMATIC SETBACK THERMOSTAT
LIGHT SENSING OR CONTACT CLOSURE
FOR LOW VOLTAGE (24VAC) SYSTEMS ONLY
REQUIRES A COMMON WIRE
Manufactured by:
LIGHTSTAT INC.
BARKHAMSTED, CT
(800)292-2444
www.lightstat.com
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CONGRATULATIONS on your purchase of a Lightstat TME. It represents
reliable, modern, electronic tempe rature control in addition to unique energy
saving features.
Features
• 1 Amp relay switching of up to 6 HVAC loads.
• Automatic Changeover from Heating to Cooling with a 5º F deadband
between heating and cooling to prevent short cycling of equipment.
• Automatic Setback of temperatures based on light sensitivity or contact
closure (model dependent).
• System ON/OFF switch, and Fan switch for AUTO or ON fan operation.
• PRE-CONDITION feature to pre-heat or pre-cool the building prior to
occupancy at the start of the day.
• Fan control settings for Heating to allow either thermostat controlled fan
(typical of electric heat) or a limit switch controlled fan (typical of gas heat).
• Auxiliary output options to permit the O/B output to be active with a call for
Heat or Cool; for heat pump reversing valve.
• A1-A2 isolated dry contact outputs for night shutdown of dampers or
equipment.
• Connections for using a Remote Room Sensor.
• Connections for using a Supply Air Sensor.
• Light Sensitivity adjustment to permit operation in bright or dim areas (model
dependent).
• Stages of Heat and Cool stagger ON.
• Proportional plus Integral control for accurate, even temperature control.
• Factory set temperature limits to prevent overheating and overcooling.
• Minimum ON and OFF time delays for compressor protection.
• Field Check button to cancel time delays for checkout in the eld.
• Fan harvests energy from coils.
• Occupancy of less than two hours will not affect pre-conditioning timing.
• Random restart after Setback or power failure.
• RTU visible alarm.
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Do not attempt to use directly with Line Voltage (120 VAC or higher),
DC (Direct Current), millivolt (thermopile), or proportional control
systems. A transformer and relays must be used to interface with
these types of systems. The Lightstat TME is designed for 24 VAC
systems only.
Pick a mounting location AWAY from drafts, windows, doors,
outside walls, and heat vents. Relocate if necessary.
The Lightstat TME senses a change in LIGHT LEVEL to determine
Setback. Mount it under lights that GO OFF when people GO
HOME. Locate the Lightstat TME at least 10 feet from a night light.
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Description
A - Current temperature.
B - Indicates if SUPPLY, REMOTE, or ROOM temperature is being displayed.
C - Setback indicator light. Glows green during Setback.
D - Visual Alarm light. Flashes red during a Roof Top Alarm signal.
E - Toggles temperature display between ROOM and SUPPLY air.
F - Temperature adjustment buttons.
G - System power button.
H - Fan ON/AUTO button.
I - Fan ON/AUTO Indicator.
J - Light Sensitivity Adjustment.
K - Illuminated ON and arrow (◄) indicate which outputs are currently ON.
Flashing arrow indicates time delay.
L - Flashing DELAY indicates the stages are held ON or OFF by a time delay.
M - Press Check button to cancel any active time delay(s).
N - Indicates temperature setpoints. Standard 5º dead-band between heat and
cool setpoints.
O - Flashes to indicate cool setpoint is at the minimum temperature limit.
P - Flashes to indicate heat setpoint is at the maximum temperature limit.
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CAUTION: Disconnect power supply before beginning installation.
Remove the old thermostat from the wall taking note of the wire colors on the
back of the mounting kit provided. Thread the thermostat cable through the hole
on the back of the Lightstat TME. Mount the Lightstat TME securely to the wall
using the hardware provided. The Lightstat TME should be leveled for cosmetic
reasons.
Connecting the Outputs
R - Hot Wire; one side of control (24-30VAC) transformer. If two hot wires are
present (as with RC and RH) determine if they come from separate transformers.
The Lightstat TME must be installed on a single transformer system.
C - Common or Neutral side of transformer. This must be connected.
O/B - This output may be active with either a call for Heat (B) or a call for Cool
(O) but not both. It is typically used for a heat pump reversing valve.
Y1 - First Stage of Cooling. There is a 1º(F) differential between any two stages
of Heating or Cooling.
Y2 - Second stage of Cooling.
W1 - First stage of Heating.
W2 - Second stage of Heat or Auxiliary heat with heat pumps.
G - Air Circulating fan. The Lightstat TME will control the fan during the cooling
cycle. Fan operation during the Heating cycle depends on the setting of switch
#4 on page 15. The Lightstat TME allows for either constant ON operation of the
fan or AUTO operation. The fan reverts to AUTO in Setback.
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System Layout
The Lightstat TME is used as a stand-alone thermostat to control a single HVAC
system. Do not attempt to control more than one HVAC unit with a Lightstat
TME.
You can add a Remote Room Sensor to sense temperature remotely.
Two Averaging Remote Room Sensors may be used to provide an average
Room Temperature (Order as Averaging Sensors).
And you can add a Supply Air Sensor to check temperature of the air coming
from your HVAC system.
Note: All wiring should be minimum #18 AWG. Shielding is not required.
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This is a eld option. You might not use this option with your Lightstat TME. You
may add this in the eld to an existing Lightstat TME.
Mount the Remote Room Sensor on the wall 5’ to 7’ off the oor, in the area to be
controlled.
Use #18 gauge 2-conductor twisted pair cable between the Lightstat TME and the
Remote Room Sensor. Remote Room Sensors are unaffected by wire runs of up
to 500 feet.
Remote Room Sensor cables do not have polarity, either wire may be connected
to either terminal. Cables do not need to be shielded.
At the Lightstat TME end connect the 2-conductor cable to the two terminals
marked Remote Room Sensor.
Note: The Lightstat TME must be powered Off and On in order to “read” a
change of switch settings.
When using a Remote Room Sensor make sure the Remote Room Sensor
switch (#5) on the inside of the Lightstat TME is set to ON. The word REMOTE
will appear in the display.
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This is a eld option. You might not use this with your Lightstat TME. You may
add this in the eld to an existing Lightstat TME.
Mount the Supply Air Sensor on the supply air duct securely with the probe
horizontal or downward.
Use #18 gauge 2-conductor twisted pair cable between the Lightstat TME and
the Supply Air Sensor. Supply Air Sensor is unaffected by wire runs of up to 500
feet.
Supply Air Sensor cables do not have polarity, either wire may be connected to
either terminal. Cables do not have to be shielded.
At the Lightstat TME end connect the 2-conductor cable to the two terminals
marked Remote Supply Sensor on the thermostat. At the Supply Air Sensor
end connect the two conductor cables to the wires on the Supply Air Sensor.
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Use #18 gauge 2-conductor twisted pair cable between the Lightstat TME and
the damper or equipment to be shut down.
A1-A2 cable does not have polarity, either wire may be connected to either
terminal. Cables do not have to be shielded.
At the Lightstat TME end connect the cable to the two terminals marked A1 and
A2. At the other end, connect it to the damper or equipment.
The A1 and A2 terminals are an isolated set of dry contacts rated at 2 amps (24-
30VAC).
They are typically OPEN during the occupied period and CLOSED during
Setback. They will OPEN during the pre-condition period.
Setting the Heat Pump / Conventional Switch (#1)
Non Lightstat Automatic Lighting Control Connections
Use #18 gauge 2-conductor twisted pair cable between the Lightstat TME and
the customer supplied switch or alternate closed contact.
C1- C2 cable does not have polarity, either wire may be connected to either
terminal. Cables do not have to be shielded.
At the Lightstat TME end connect the cable to the two terminals marked C1
and C2. At the other end connect it to the customer supplied switch or alternate
closed contact.
The C1 and C2 terminals are contact closure terminals and should not be
connected to any power.
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The Lightstat TME has a visual alarm to indicate that there is a problem with the
Roof Top Unit (RTU). This is a eld option. You might not have this option with
your specic RTU.
Use #18 gauge 2-conductor cable between the Lightstat TME and the RTU. The
alarm is unaffected by wire runs of up to 1000 feet.
If the alert does not function correctly, verify proper installation of wiring
and jumper.
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Setting the Heat Pump / Conventional Switch (#1)
Note: The Lightstat TME must be powered Off and On in order to “read” a
change of switch settings. Moving this switch to the ON position will increase the
heating Setback by 5° (F). This will allow a heat pump to stay in a compressor
mode longer and avoid expensive electric resistance heat.
Note: When connecting a Lightstat TME to a heat pump with Thermostat
Reversing Valve Control you will need to install a jumper wire between W1 and
Y1 at the Lightstat TME as shown in the diagram above.
Note: When connecting a Lightstat TME to a heat pump with Unit Reversing
Valve Control no jumper wire is required as the reversing valve is positioned by
the unit internal controls based on whether cooling or heating is being called by
Y1, Y2 or W1, W2.
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Setting the Compressor Time Delay Switch (#2)
Note: The Lightstat TME must be powered Off and On in order to “read” a
change of switch settings.
When this switch is set to OFF, the minimum On and Off time for any stage of
Heating or Cooling will be 3 minutes.
When set to ON, there will be no minimum On and Off time for any stage of
Heating or Cooling.
In either position, the Fan will continue to run for 45 seconds after the Heating
or Cooling stops; unless the Fan switch is set to ON, in which case the fan runs
continuously.
During Setback the Fan will revert to the Auto Mode.
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Setting the O/B (Aux) Switch (#3)
Note: The Lightstat TME must be powered Off and On in order to “read” a
change of switch settings.
The position of the O/B switch will determine whether the O/B output comes on
with a call for Heating or for Cooling.
In the OFF position it will remain latched On during the Cooling Cycles (O) until
there is a call for Heating.
In the ON position it will remain latched On during the Heating Cycles (B) until
there is a call for Cooling.
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Setting the Heat Fan Switch “Gas/Electric” (#4)
Note: The Lightstat TME must be powered Off and On in order to “read” a
change of switch settings.
This is often called the “Gas/Electric” switch. Consult the HVAC equipment
manufacturer instructions for details on how to set this switch.
When controlling fossil fueled equipment with a fan limit control you may want to
set this switch to the On position.
Note: The Lightstat TME will not bring on the fan in this setting during the heat
cycle.
Leave this switch set to Off for all other equipment.
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Setting the Remote Room Sensor Switch (#5)
Note: The Lightstat TME must be powered Off and On in order to “read” a
change of switch settings.
This will tell the Lightstat TME to ignore the on-board temperature sensor.
You will see the word REMOTE appear in the display indicating the Remote
Room Sensor switch has been moved to ON.
A “00” in the display indicates no remote sensor is connected.
A “99” in the display indicates there is a short (the two wires are touching) in the
Remote Room Sensor wiring.
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Setting the Pre-Condition Countdown
Your Lightstat TME has the ability to come on before the lights do.
Note: The Lightstat TME must be powered Off and On in order to “read” a
change of switch settings.
Set the dial for the number of hours that the lights in the facility will be off when it
is closed, and the Lightstat TME will automatically come on early enough to bring
up the heat or cool down before occupancy.
Choose the number of hours the facility is unoccupied from the top list. Set the
dial to the corresponding character from the lower list.
The Lightstat TME looks at how long the time is before occupancy and how far
away from the heating and cooling setpoints the temperature is. It calculates how
long it will take to heat up or cool down, and operates the equipment accordingly.
Remember to count the total average time of darkness expected during
unoccupied times. If all the days do not have the same length of darkness,
choose the period used for most days of the week. The Lightstat TME can only
remember one schedule.
For example, if your facility is occupied from 8:30 AM to 9:30 PM from Monday to
Saturday but only open a few hours on Sunday; choose 11 hours and set the dial
to “B”.
The Lightstat TME will go back into Setback if the lights remain off after the Pre-
Condition period. Thus, if a facility is closed on Sunday, the Lightstat TME will go
back into Setback and pre-condition for Monday.
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Powering Up the Lightstat TME
First you must turn on the breaker or switch that feeds power to your
Lightstat TME.
Next press the System On/Off button, if necessary, to turn on the Lightstat TME.
The power-up sequence will give you information on your Lightstat TME.
Sequence Display Symbol Meaning
First All Characters On Veries all display characters
Second Cool Set Factory Min Cool Setting
Heat Set Factory Max Heat Setting
Temperature --
Third Cool Set Factory Cooling Setback
Heat Set Factory Heating Setback
Temperature Pre-Condition Period
Fourth Cool Set --
Heat Set --
Temperature Max Pre-Condition Period
Fifth Cool Set Software Revision #
Heat Set Software Revision #
Temperature --
Determining Your Lightstat TME Setback Control
If your Lightstat TME has a clear window then go to Adjusting the Light
Sensitivity below.
If your Lightstat TME does not have a clear window, then it will not respond to
light changes. It is most likely controlled by the Lightstat TME Automatic Lighting
Control (ALC), customer supplied switch or alternate contact closure. No action
is required.
Adjusting the Light Sensitivity
You will want to make sure the Lightstat TME sets back temperatures when the
lights are turned down in the room where the Lightstat TME is located.
The clear plastic window on the top of your Lightstat TME is where it senses the
light. If you shadow the window at the top of the Lightstat TME, it will cause it to
shift to the Setback mode. It will signal this by turning on the GREEN SETBACK
LIGHT. When the Setback light is on, the Cool Set and Heat Set temperatures
will show the Setback temperatures, which are model specic and not adjustable.
You will make the Lightstat TME go into Setback mode more easily by moving
the LIGHT SENSITIVITY ADJUSTMENT slide to the right, toward BRIGHT.
If the Lightstat TME goes into Setback mode when the room is occupied, you
can make it less sensitive by moving the LIGHT SENSITIVITY ADJUSTMENT
slide to the left, toward DIM.
Turn off the lights in the room around the Lightstat TME and make sure that the
GREEN SETBACK LIGHT comes on.
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Using the Lightstat TME
Use the SYSTEM ON/OFF button to turn your HVAC equipment On and Off.
Use the DISPLAY button to shift the temperature display from ROOM
temperature to SUPPLY temperature. The SUPPLY temperature is the air
temperature coming from your HVAC system. You will have to install a Supply Air
Sensor in order to read this temperature. If you do not have this sensor installed,
then the display will read “00”.
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The FAN ON/AUTO button will shift the fan operation from continuous to cycling
with a call for heating or cooling. If the fan is left in the FAN ON mode during
occupancy, it will automatically shift to AUTO FAN during Setback.
The CHECK button is used to cancel any safety time delays. These time delays
are to protect the equipment from short cycling, and to prevent multiple HVAC
systems from coming on at the same time after a power failure or with the lights.
If you see the word DELAY ashing, then the Lightstat TME is in a time delay.
The startup time delay can be as long as 12 minutes.
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Setting the Temperature
Use the UP and DOWN temperature buttons to set the heating and cooling
setpoint. To conserve energy and make sure that the adjacent HVAC units do not
ght each other, the Heating and Cooling setpoints cannot be set closer together
than 5° (F).
The range of the temperature adjustment is factory restricted to owner
specications.
Thus you can only adjust the heating setpoint up to a maximum HEAT LIMIT.
When you reach the HEAT LIMIT, the heating setpoint will stop and the display
will ash HEAT SET ‘AT MAXIMUM’. The cooling setpoint can continue to be
adjusted higher.
Likewise, the cooling setpoint has a minimum COOL LIMIT. When you move
the cooling setpoint down, the cooling setpoint will stop at the COOL LIMIT. The
display will ash COOL SET ‘AT MINIMUM’. The heating setpoint can continue to
be adjusted lower.
The HEAT LIMIT and COOL LIMIT for your model Lightstat TME are identied
during the power-up sequence. See page #18 for more information.
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Output Status
Your Lightstat TME will tell you what the output status of the HVAC
system is.
When you see the word ON in the display, the Lightstat TME is turning that
output On.
A ashing ◄ (arrow) next to the word ON means that the output is held on for a
minimum time period; for example, 3 minutes.
A ashing ◄ (arrow) without the word ON means the output is being held off for
a minimum time period.
Whenever a delay is in effect, the word DELAY will also ash above the
indicators.
Note: Use the CHECK button to cancel time delays for quicker checkout.
You can use the output indicators to help troubleshoot your HVAC system. If
the Cool 1 and Cool 2 output indicators are displayed, you should feel cool air
coming from the HVAC system. If a Supply Air Sensor is installed, you should
read the temperature of the cool air coming from the unit.
This tells you the HVAC system is working properly.
Checking Heating and Cooling Beyond Maximum Limits
Lightstat TMEs are designed to heat and cool to owner dened maximum limits.
The maximums for your particular Lightstat TME are shown during the power-up
sequence described on page 18.
While testing the HVAC system there may be times when you want to force
the Heating on during the summer when the room temperature is well above
the Heating Maximum. You do this by pushing and holding the Up Button and
the CHECK button at the same time. Outputs will only remain on while you are
pressing both buttons.
You can also force the Cooling on by pushing the Down Button and the CHECK
button at the same time. This will force the cooling on while you are pressing both
buttons.
Make sure that the Lightstat TME is in the occupied mode when you do this. The
Green Setback light should be Off.
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Visual Alarm
Your TME is equipped with a visual alarm which will allow you to know if there is
an issue with your Roof Top Unit (RTU).
This helps in preventing a small problem from becoming a large one, thus saving
time, money and RTU down-time.
If the RTU has an alarm signal connection, when something is not working properly, it will send an alarm signal to the thermostat.
When this occurs a red ashing light will be visible in the Setback window.
If this occurs contact your maintenance department so the issue can be
corrected.
The visual alarm will continue to ash until the RTU issue has been corrected
and/or the RTU signal reset.
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Questions... Call Tech Support at 800-292-2444
Symptom Possible Cause Solution
No Operation of
Heating or Cooling
Lightstat TME Power Off. Press the System ON/OFF
button.
No Power to equipment or
Lightstat TME.
Check switches, circuit
breakers, fuses, gas valve and
pilot.
Lightstat TME in Night
Setback.
See Light Adjustment on Page
19.
Lightstat TME at limit
temperature.
Check Display to verify the
Lightstat TME is set at its
Cooling Minimum or Heating
Maximum.
Display does not
come on during
Power-up
No power to the Lightstat
TME.
Verify 24 VAC is present at
terminal block by measuring
from R to C. If no voltage
present check breakers and
fuses.
Fan Blows Cold air in
Heating Season
Fan ON/AUTO is in the
wrong position.
Move Fan to Auto position by
pressing the FAN ON/AUTO
button.
Heat Fan Switch in wrong
position.
See setting the Heat Fan
switch on Page 15.
O/B switch set to wrong
position for Heat Pump.
See setting the O/B Switch on
Page 14.
Heating or Cooling
will not come ON
O/B switch set to wrong
position for Heat Pump.
See setting the O/B switch on
Page 14.
Time Delay holding Heating
or Cool Off.
Press the Check button to
cancel the time delays.
Green Setback Light
Stays ON or OFF
Improper Light Sensor
adjustment.
See Light Adjustment on Page
19.
Basic Troubleshooting
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Symptom Possible Cause Solution
Display shows Room
Temp as “00”
The Remote Temp Sensor
switch #5 is set to ON, but
there is no Remote Room
Sensor connected.
Turn off the Lightstat TME
and move switch #5 to the
OFF position, then cycle the
Lightstat TME power.
There is a Remote Room
Sensor installed, but the
wiring connections are not
correct.
Check the wiring connections
for the Remote Room Sensor.
Display shows Room
Temp as “99”
There is a Remote Room
Sensor installed but the
wiring connections are
incorrect.
Check the wiring connections
for the Remote Room Sensor.
Display shows
Supply Temp as “00”
There is no Supply Air
Sensor installed or the wiring
connections are incorrect.
Check the wiring connections
for the Supply Air Sensor.
Display shows
Supply Temp as “99”
There is a Supply Air Sensor
installed but the wiring
connections are incorrect.
Check the wiring connections
for the Supply Air Sensor.
The Lightstat TME
powers up correctly,
but the display goes
blank
Transformer is too small
for the installation.
The Lightstat TME needs a
minimum of 21VAC to operate.
You may have to install a
larger transformer to provide
adequate power to keep the
voltage at 24VAC.
The Lightstat TME resets
when outputs come on.
Check for a wiring short.
The cooling
temperature can be
set higher but not
heat
The Lightstat TME is at its
heating maximum.
The Lightstat TME has owner
specied Limits to prevent
overheating. You cannot set the
heating temperature above this
limit.
The heating
temperature can be
set lower, but not the
cooling
The Lightstat TME is at its
cooling minimum.
The Lightstat TME has owner
specied Limits to prevent
overcooling. You cannot set the
cooling temperature below this
limit.
Visual alarm is not
working.
The jumper on the
thermostat is in the incorrect
position.
Verify the jumper is in the
correct position.
(AC/DC versions only) The
wires are not connected to
the terminals correctly.
Measure the signal to verify the
polarity of wiring is correct at
the thermostat.
There is a break in the wire
from the RTU.
Verify the correct signal is at
the terminal blocks on the
thermostat.
Basic Troubleshooting
Lightstat Limited Lifetime Warranty
Lightstat Inc. warrants that all Hardware Products (Products) sold by it after October 1, 2015 are free
of defects in material and workmanship, under normal use and service for as long as the Products are
installed in their original installation for the original End User and operator of the Products with the
following limitations:
1. In the event of Product discontinuance, warranty support is limited to ve (5) years from the
announcement of discontinuance.
2. The duration of the warranty period for Products not designed or manufactured by Lightstat
(e.g. power supplies, Ethernet cables, motion sensors, etc) and mechanical assemblies that are
subject to normal wear and tear (e.g. timers, electrical contractors, relays) shall be two (2) years
from the time of purchase.
3. This warranty does not apply to any Product which was not operated in accordance with the
printed instructions, has been damaged by accident or acts of God or which has been misused,
abused or neglected or has been damaged by other cause. This warranty also does not apply
to any Product, which was maintained, altered or repaired by anyone other than Lightstat or its
authorized representatives.
4. This warranty is conditioned upon (a) proper storage, installation, use and maintenance and
conformance with any applicable recommendations of Lightstat and (b) Customer promptly notifying
Lightstat of any defects and, if required, promptly making the Product available for correction.
All claims for nonconforming or defective Products must be made within the warranty period. Any claim
not made within that period shall be deemed waived and released. Lightstat’s sole responsibility with
respect to such claims shall be, at its option, to repair or replace any Product or component that it determines to be defective. Replaced Products may be refurbished or new equipment at the option of Light-
stat. Such Product must be removed by the installer and returned to the factory within the applicable
warranty period with transportation charges, if any, prepaid, after rst obtaining proper authorization and
shipping instructions by contacting Lightstat. Any repaired or replacement Product shall be warranted
for the remaining period of the original Warranty Period. Repair or replacement as provided under this
warranty shall be the exclusive remedy of the Customer.
In no event, shall Lightstat be responsible for any monetary damage or be liable for any incidental or
consequential damages due to any cause whatsoever, including, without limitation, commercial loss or
damage resulting from an alleged defect in the Product.
Lightstat does not authorize any other person or organization to assume for it any liability in connection
with this Product and any statements or representations made by any other person or organization
are void.
EXCEPT FOR THOSE WARRANTIES EXPRESSLY SET FORTH IN THIS AGREEMENT, LIGHTSTAT INC. DISCLAIMS ANY AND ALL OTHER WARRANTIES, EXPRESS IMPLIED, STATUTORY,
OR OTHERWISE INCLUDING, BUT NOT LIMITED TO, ALL WARRANTIES OF FITNESS FOR A
PARTICULAR PURPOSE OR MERCHANTABILITY. LIGHTSTAT INC. MAKES NO ADDITIONAL EXPRESS OR IMPLIED WARRANTIES EXCEPT TO THE EXTENT, IF ANY, THEY ARE SPECIFICALLY
REQUIRED BY LAW.
Some states do not allow the exclusion or limitation of implied warranties or consequential damages, so
the above limitations or exclusions may not apply to the purchase of this Product. This warranty gives
each original purchaser specic legal rights, and such purchaser may have other rights that vary from
state to state.
Lightstat Inc. ٠ 22 W. West Hill Road ٠ Barkhamsted, CT 06063 ٠ USA ٠ 800.292.2444
sales@lightstat.com ٠ www.lightstat.com ٠ © 2016 Lightstat Inc. All Rights Reserved. Made in USA.
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