Troubleshooting and Support

Troubleshooting and Support

If you have difficulty with your thermostat, please try the following suggestions. Most problems can be corrected quickly and easily.

Video: Troubleshooting Common Thermostat Wiring and Installation Issues

Display Behavior Is Not As Expected

Display is blank:

Check circuit breaker and reset if necessary.
Make sure power switch for heating & cooling system is on.
Make sure furnace door is closed securely.
Make sure the C wire is connected.

Cannot change temperature setpoint:

Verify the thermostat is set to the correct mode. Touch Mode to change mode setting.
If the display indicates “Setting locked” when you touch the up or down arrow, you can unlock the screen by selecting Menu > Screen lock.
The thermostat may be preventing you from changing the set-point above or below a certain setting because of minimum and maximum settings. Menu > Preferences > Temperature limits.
Default minimum and maximum settings:

Heat: 40 °F to 90 °F (4.5 °C to 32.0 °C)
Cool: 50 °F to 99 °F (10.0 °C to 37.0 °C)

Weather menu isn’t displayed:

This menu is only shown when the thermostat is connected to WiFi and the app. If WiFi connection is lost, the thermostat will not show that option until connection is restored.

Display temperature is inaccurate (reads too high or low)

There are different reasons that the room temperature reading on the thermostat may be reading higher or lower than expected.

“Feels Like Temperature” is a setting that can make the indoor temperature reading show a few degrees warmer when relative humidity is high. See Feels like Temperature.
Indoor display offsets can be set to make the display read up to 3 degrees higher or lower than the sensor reading or +/- 12% RH from the humidity sensor reading. See Indoor Display Offsets.
If one or more wireless sensors is used, the thermostat can be set to measure temperature at the thermostat, a wireless sensor, or an average reading. See Priority.
If a sensor is wired to the S terminals on UWP, feedback on that sensor can cause display accuracy issues. Even if the thermostat is set to a wired outdoor sensor, if that sensor is wired in parallel to another thermostat or zone panel or getting feedback some other way, this can drastically affect the indoor temperature reading.

Menu options are not shown

When Menu is selected, the display shows menu options and allows the user to scroll left or right to see additional options. Some options may not be shown if the thermostat is not set to support those settings such as humidification. If the display is set for a lockout, many of the menu options are not shown. Select MENU > SCREEN LOCK to view lockout status. The lockout status should only be changed by the thermostat owner and there may be an option to require a password in order to unlock the screen.

Heating or Cooling Issues

Heat runs with thermostat in cool or off mode:

If this happens immediately after installation, the thermostat may be wired or configured incorrectly. Shut off power for the heating/cooling system at the breaker and call technical support or an HVAC Pro.

Heat doesn’t come on:

When in the heat or emergency heat mode and not calling for heat, the display shows “heat to”.

When calling for heat or emergency heat the display shows “heating to”.

If display is showing “WAITING FOR EQUIPMENT” above the room temperature it is in a delay mode to protect the equipment. If the delay lasts longer than 5 minutes, see WAITING FOR EQUIPMENT stuck in display.

If display is not showing “WAITING FOR EQUIPMENT”, verify the thermostat is set to Heat, Em Heat, or Auto mode and verify that the heat setpoint is above room temperature. Does the display indicate “Heating to” (rather than "heat to") above the set point?

If “HEATING TO” is displayed, and heat does not come on after a short delay, have the installer verify wiring connections and R/Rc slider switch on UWP are good.

If “HEAT TO” (rather than "HEATING TO") is displayed above the setpoint, but heat set point is above room temperature, go to EQUIPMENT STATUS and see if any reason is given for why heat is not running.

Check for any active alerts.

Cooling doesn’t come on:

When in the cool mode and not calling for cooling, the display shows “cool to”.

When calling for cooling the display shows “cooling to”.

If display is not showing “WAITING FOR EQUIPMENT”, verify the thermostat is set to cool, or Auto mode and verify that the cool setpoint is below room temperature. Does the display indicate “cooling to” (rather than "cool to") above the set point?

If “COOLING TO” is displayed, and heat does not come on after a short delay, verify the wire connections, R/Rc slider jumper on UWP (or R, Rh, and Rc jumpers if an EIM is used). If those variables check out, your HVAC contractor can call Tech Support to verify configuration and for further troubleshooting.

If “COOL TO” (rather than "COOLING TO") is displayed above the setpoint, but cool set point is below room temperature, go to EQUIPMENT STATUS and see if any reason is given for why cooling is not running.

Check for any active alerts.

WAITING FOR EQUIPMENT stuck in display

If display shows “WAITING FOR EQUIPMENT” then the thermostat is holding off running the heating or cooling to prevent short cycling or because of a lockout condition. The short cycling delay should last 5 minutes at most, but an alert lockout will keep that equipment locked out until the alert condition is resolved. The short cycling delay most commonly would occur on start up, after a power loss, or if someone adjust setpoint within 5 minutes of equipment shutting off.

If you time this and it shows "WAITING FOR EQUIPMENT" for longer than 5 minutes.

See if there are any active alerts.
It is possible there is an intermittently power loss to the thermostat. As a test the installer could remove all wires besides R and C from UWP and then test the heat or cooling. If the thermostat then indicates a call for heat or cooling within 5 minutes, a shorted wire or high equipment draw could be interrupting power to the thermostat momentarily at the start of a heat or cooling call.

Cooling runs below set point:

Verify the cooling is running while cool set point is above the room temperature reading on the display. If so, verify the thermostat is deliberately running cooling. When doing so, the display shows “Cooling to” (rather than “COOL TO”). Also, menu equipment status will show if the thermostat is trying to run cooling or not.

If the display shows “Cooling to” and a setting that is above the room temperature reading it is likely the X8S & X8Q Smart Thermostat has been set to over-cool when humidity is high.

See Indoor Air Quality Control and Monitoring. If over-cooling is not desired, go to the dehumidification menu and turn dehumidification off.

Heat runs when room temperature reading is above the heat setpoint:

If the thermostat is not in heat mode, see “Heat runs with thermostat in cool or off mode”.
If the thermostat is in heat or emergency heat mode, verify whether the display indicates a call for heat.

If display shows “HEAT TO” over setpoint, the heat should not be running.

If the display shows “HEATING TO” over setpoint, the thermostat is trying to run the heating.

Display shows HEAT TO and heat is running.

The thermostat is not trying to run the heating at this time.

Display shows HEATING TO and heat is running.

The thermostat is trying to run the heating at this time. It is unusual that the thermostat would run heat if the room temperature reading is above the setpoint in thermostat display. Check equipment status.

Fan Issues

Fan will not run when expected

If the thermostat is set to control a heat-only system such as a boiler, there will not be a fan setting. Menu > Equipment Status will show the fan state.

The X8S & X8Q Smart Thermostat can have the fan set to on, auto, or circ for each schedule period. See Fan Scheduling.

Fan is running unexpectedly

The X8S & X8Q Smart Thermostats have different settings that might have turned on the fan. Check Menu > Equipment Status to see what the thermostat indicates it is running.
The thermostat could be set to run the fan with a call for ventilation, humidification, or dehumidification.
The thermostat will also run the fan with a call for cooling and in forced air heat systems the fan will also run with a call for heat (but this may or may not be controlled by the thermostat depending on the system type settings).
The X8S & X8Q Smart Thermostat can have the fan set to on, auto, or circ for each schedule period. See Fan Scheduling.
If the thermostat doesn’t indicate the fan is on under the EQUIPMENT STATUS menu, it is possible something else in the system is controlling the fan such as a separate control for a humidifier, dehumidifier or ventilator.

Fan mode changes by itself

See the Fan is running unexpectedly or Fan will not run when expected.

Wireless sensor issues

I cannot pair a wireless sensor to my X8S & X8Q thermostats?

A: If the sensor had been paired with a previous thermostat, you first need to reset that sensor. Remove the cover and press/hold the button for approximately 15 seconds to clear it. On the thermostat touch Menu > Devices and sensors > Add. With the sensor at least 3 feet from the thermostat, press/release the button on the sensor. If the LED never flashes, verify the batteries are fresh and installed correctly. If the sensor light flashes but the thermostat display does not indicate that it has connected to the sensor, verify sensor compatibility. See Q: Which wireless sensors and accessories work with X8S & X8Q thermostats?.

Wi-Fi and app-related issues:

See WiFi Setup and Troubleshooting.

Customer Assistance

Call Resideo Customer Care toll-free at 1-800-633-3991.

2-year limited warranty

For Warranty information go to resideo.info/US-Warranty-THERMOSTAT