Support for FlatStat

Frequently Asked Questions

Symptom:  This is usually caused by a high temperature safety limit opening on the furnace. When the safety opens, the furnace shuts off the burners and disconnects the 24VAC to the thermostat causing the thermostat clock to stop.  In order to cool down the heat exchanger, the furnace blower will remain energized for approximately 15 minutes before restoring power to the thermostat and, if there is still a call for heating, allowing the furnace to re-energize.  In this situation homeowner may never notice a problem, except that the clock will be off by the number minutes power was disconnected.

Correction: Determine what is causing the high temperatures to occur - dirty filter, etc.

Symptom:  The “PF” error code applies only to our power-stealing line of thermostats* and stands for Power Failure.  This occurs when there is a significant drop in voltage to the thermostat.

Correction: you must install a common wire between the equipment and thermostat. Please refer to FAQ “How to Add a Common Wire”.

If you have installed a common wire, check it for continuity and that it is connected at both ends.

Symptom:  Many of our thermostats have the ability to, in addition to other security features*, lock out the thermostat buttons entirely.

Correction: To lock or unlock the thermostat buttons, press and hold the MODE button.  While you are holding the MODE button, press the UP and DOWN arrow buttons as well.

*NOTE:  Many of our commercial thermostats have advanced security features that also disable certain button functions.  If some, but not all, of your buttons are locked out, then you will need to disable the security setting.  Consult the Owner’s Manual of the thermostat in order to disable the security setting of your thermostat.

Symptom:  This security feature is only applicable to our non-battery, 4-button thermostat models.  The first two setup steps deal with the time of day and day of the week.  Any steps beyond these two, such as the equipment settings (heat pump or gas/electric) or compressor protection timers are locked out to protect the end-user from disabling or possibly damaging their equipment.

Correction:  To access the rest of the advanced setup steps, press and hold the MODE and FAN or, on commercial models, MODE and OVERRIDE buttons.  When the screen enters the advanced setup, you must continue to hold down the MODE and FAN or, on commercial models, MODE and OVERRIDE buttons for seven additional seconds (if you release the buttons before this time, you will be locked out of the rest of the advanced setup).

Symptom: The temperature reading of thermostat may be incorrect due to the incorrect connection of the sensor, electrical interference on the remote sensor wiring, a wall location that receives very little airflow, and/or proximity to devices that emit heat.

Correction #1:  Check to see if the degree symbol is flashing.  If it is not flashing, the remote sensor reading is not being displayed.

Correction #2: Check your wiring.  The Remote Sensor should be connected to the thermostat using solid conductor CAT 5, CAT 5e, or CAT 6 type network communication cable. This is an unshielded cable with four twisted pairs of 24 gauge solid wire; DO NOT use stranded cable.  The cable length should not exceed 250 feet.  If less than 75 feet of cable is required to connect the thermostat to the Remote Sensor, a three conductor thermostat cable (18-24 gauge) may be used; this cable is NOT suitable for any length greater than 75 feet.

IMPORTANT:  Do not use shielded wire.  Do not run sensor wiring in the same conduit as the 24VAC thermostat wiring.  Electrical interference may cause the sensor to give incorrect temperature readings.

Four Button Models – press the MODE and DOWN buttons at the same time until all of the icons appear.  Then press the MODE button one or two times until the current room temperature appears.  Use the UP or DOWN button to adjust the temperature.  Press the MODE button one or two times to exit calibration.

Eight Button Models (with a door) – press the MODE and FAN buttons at the same time until all of the icons appear.  Then press the UP and DOWN buttons at the same time twice.  When the current room temperature appears, press the MODE button once more to display the remote sensor calibration screen.  Use the UP or DOWN button to adjust the temperature.  If the thermostat does not have a remote sensor calibration screen, then calibrate the remote sensor in the normal temperature sensor screen.  Press the MODE button one, two, or three times to exit calibration.

NOTE: Do not use an ohmmeter to test the sensor - these are digital sensors, not thermistors, and they can be damaged by an ohmmeter. 

Symptom:  When the thermostat is placed on a wall that has no insulation, air will often blow on the thermostat sensor from behind the wall.  This air will remain the same temperature even though the space temperature is being heated or cooled.

Correction:  Insulate the hole behind the thermostat with insulation, spray foam, or even duct tape - whatever will stop the airflow from behind the wall.

Symptom #1:  This usually occurs when a gas/electric thermostat is attempting to control a heat pump system.

Correction #1:   If your thermostat is heat pump compatible, follow the instructions below to program the thermostat for heat pump operation.  This will entail changing the jumper settings on the thermostat circuit board or selecting heat pump operation in the advanced setup programming.

Jumper Setting – Pull your thermostat away from the sub-base.  The jumpers will be located in the upper right hand corner of the circuit board.  Locate the middle jumper that can be set for GAS or HP operation.  Place the jumper on the two pins closest to HP.

Advanced Setup – Press the MODE and PROGRAM or MODE and FAN buttons to enter advanced setup.  Then press the MODE button repeatedly until HP appears in the middle of the screen.  Press the UP button so that ON is displayed.  Press PROGRAM or MODE and FAN to exit advanced setup.

Symptom #2:   This may also occur when the reversing valve setting of a heat pump compatible thermostat has been programmed incorrectly. 

Correction #2:   Follow the instructions below to program the thermostat for the correct reversing valve setting.  This will entail changing the jumper settings on the thermostat circuit board or selecting the operation in the advanced setup programming.

Jumper Setting – Pull your thermostat away from the sub-base.  The jumpers will be located in the upper right hand corner of the circuit board.  Locate the bottom jumper that can be set for O or B operation.  Place the jumper on the two pins closest to the correct reversing valve setting.

Advanced Setup – Press the MODE and PROGRAM or MODE and FAN buttons to enter advanced setup.  Then press the MODE button repeatedly until HP appears in the middle of the screen.  Now press the MODE button once.  ‘O’ or ‘b’ will appear on the display.  Press the UP or DOWN button to display the correct reversing valve setting.  Press PROGRAM or MODE and FAN to exit advanced setup.

NOTE:  If your system is a commercial heat pump, then the thermostat may not need to be programmed for heat pump operation.  Commercial heat pumps usually require gas/electric thermostats for proper operation.  If the terminal connections in the equipment do not have an ‘O’ or ‘b’ terminal, but do have a ‘W1’ or ‘W’ terminal, then a gas/electric thermostat will most likely be required.

Symptom: This usually occurs when a heat pump thermostat is attempting to control a gas/electric system.

Correction:   If your thermostat is gas/electric compatible, follow the instructions below to program the thermostat for gas/electric operation.  This will entail changing the jumper settings on the thermostat circuit board or selecting gas/electric operation in the advanced setup programming.

Jumper Setting – Pull your thermostat away from the sub-base.  The jumpers will be located in the upper right hand corner of the circuit board.  Locate the bottom jumper that can be set for GAS or HP operation.  Place the jumper on the two pins closest to the GAS.

Advanced Setup – Press the MODE and PROGRAM or MODE and FAN buttons to enter advanced setup.  Then press the MODE button repeatedly until HP appears in the middle of the screen.  Press the DOWN button so that OFF is displayed.  Press PROGRAM or MODE and FAN buttons to exit advanced setup.

Symptom: Some types of heating systems require the thermostat to operate the indoor fan (like electric heat and, of course, heat pump systems).

Correction:  Program the Electric Heat (EH) setting of your thermostat.  This will entail changing the jumper settings on the thermostat circuit board or selecting electric heat (EH) operation in the advanced setup programming.

Jumper Setting – Pull your thermostat away from the sub-base.  The jumpers will be located in the upper right hand corner of the circuit board.  Locate the top jumper that can be set for EH or GAS operation.  Place the jumper on the two pins closest to EH.

Advanced Setup – Press the MODE and PROGRAM or MODE and FAN buttons to enter advanced setup.  Then press the MODE button repeatedly until EH appears in the middle of the screen.  Press the UP button so that ON is displayed.  Press PROGRAM or MODE and FAN to exit advanced setup.

This is a common problem when replacing a mechanical thermostat or a thermostat powered by batteries. These older thermostats require 4 wires, but newer more sophisticated thermostats require a 5th wire known as the Common wire to power the digital display. There are three ways to add the common wire to a four wire installation:

Note: Before starting, we recommend that you take a picture of the original wiring to the old thermostat as reference to help remember what terminal each thermostat wire was connected to.

Option #1: The easiest and least expensive option is to sacrifice independent control of your indoor fan.

  1. First, disconnect power from your heating and/or cooling system.

    Caution: if your heating and cooling system is powered during the thermostat installation process and you accidentally touch the R (red) power wire to the C (blue or brown) common wire, then you will permanently damage either the equipment fuse or the transformer in the equipment.

  2. After disconnecting power from your heating and/or cooling system, move the wire connected to the G terminal (typically green) that controls your indoor fan to the C terminal (common) on the thermostat.
  3. At your heating and cooling equipment repeat the same step and move the G terminal wire to the C terminal.
  4. At your heating and cooling equipment place a jumper wire from the Y equipment terminal to the G equipment terminal. This will allow the fan to turn on when the thermostat is calling for cooling or heating but it will not give you independent fan control from the thermostat.
  5. See diagram below for wiring instructions.
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Option #2: The second way to add a wire is to install the ACC0410 Add-A-Wire accessory. Add-A-Wire allows two thermostat signals to be controlled from one thermostat wire. As above move the green wire from the G terminal to the C terminal on the thermostat and at your heating and cooling equipment. Now use the Yellow wire to carry the Add-A-Wire signal.  image

Add-A-Wire Diode and Add-A-Wire Box:

image image

Add-A-Wire Model #ACC0410 In applications where additional wiring cannot be run, the Add-A-Wire accessory can be used to add a wire to the thermostat.

  • Easy to install
  • Easier than running new wire
  • Allows 5 wire thermostats to use only 4 wires
  • Also allows 5 wires to work like 6 wires

Option #3: The final way to add a wire is to contact a licesned HVAC contractor. This contractor will be able to run the necessary number of thermostat wires from your heating and cooling system to your thermostat. Please visit the Distributors section of our website to find the nearest HVAC wholesale distributor to your location. You may contact any of these distributors for an HVAC contractor referral in your area.

Literature/Manuals

FlatStat (Residential)

Model T1100FS - Literature

FlatStat (Commercial)

Model T0051FS - Literature

IMPORTANT SUPPORT NOTE

Venstar thermostats are sold only to authorized distributors in North America. Our distributors sell our products to their dealers and contractors. Most of these dealers/contractors sell & professionally install Venstar products. A few of these dealers sell Venstar products online through their own website or through an online retailer such as Amazon. Venstar itself does not sell thermostats direct to the consumer or online.

As the manufacturer of Venstar branded thermostats we offer training and support primarily to our distributors and their dealer/contractors.

Your place of purchase should be your first avenue of support. That being said, Venstar technicians will make every effort to answer your thermostat support questions by email. From this page you may access basic troubleshooting and helpful tips.