the schedule i set on my lux geo keeps disappearing or resetting to default.

Diagnosis

The Lux GEO WiFi Thermostat relies on a combination of constant 24VAC power and internal battery backup to maintain its volatile memory (RAM), where your custom scheduling data is stored. When the device experiences a power dip or a complete loss of current, it attempts to switch to the internal backup batteries. If those batteries are depleted or if there is a voltage drop across the C-wire (Common wire) connection, the memory clears, and the device reverts to its factory default "Out of the Box" schedule. This issue is most common in systems that rely on "power stealing" (where the thermostat draws power from the R and W/Y wires) rather than a dedicated C-wire. In these setups, when the system isn't actively running heat or cool, the voltage can drop below the threshold required to keep the WiFi chip and memory active. You can confirm this by checking if the screen flickers or if the WiFi disconnects shortly before the schedule resets. If the thermostat is losing its connection to the 2.4GHz network simultaneously with the schedule wipe, it is almost certainly a power delivery failure.

How to Fix It

To permanently resolve the schedule resetting issue, you must stabilize the power supply and refresh the backup cells. Follow these exact steps:

1. Replace Backup Batteries: Remove the thermostat faceplate from the wall bracket. Locate the battery compartment on the back. Replace the existing batteries with two fresh, high-quality Alkaline AAA batteries. Do not use rechargeable batteries, as their lower nominal voltage (1.2V vs 1.5V) can trigger low-power resets.
2. Verify C-Wire Connection: Inspect the wiring at the wall plate. Ensure there is a wire connected to the 'C' terminal. If you see a wire tucked into the wall that isn't connected, strip 1/8 inch of insulation and secure it into the C terminal.
3. Test Voltage: If you have a multimeter, set it to AC voltage and measure between the R and C terminals. You should see a steady reading between 24VAC and 28VAC. If the reading is below 22VAC, your transformer is undersized or failing.
4. Install a C-Wire Adapter: If your home lacks a C-wire, do not rely on power stealing. Install a 24V C-wire adapter (such as the Lux-specific adapter or a generic Add-a-Wire kit) at the furnace control board. This ensures a constant current loop to the thermostat.
5. Hard Reset and Reschedule: Once power is stabilized, perform a factory reset by navigating to Menu > Settings > Reset. After the reboot, re-enter your schedule and wait 24 hours to confirm the settings persist through a heating/cooling cycle.

If That Didn't Work

• Check for Firmware Updates: Access the Lux GEO app on your smartphone. Navigate to Device Settings and check for a firmware update. Early versions of the GEO software had a bug where the schedule would overwrite itself during a cloud synchronization error; updating the firmware patches this logic flaw.
• Inspect the Transformer: If you have multiple smart devices (thermostats, smart switches) on one 24V transformer, you may be experiencing "voltage sag." Replace your standard 40VA transformer with a 50VA or 75VA transformer to provide more headroom for the WiFi radio.
• Analyze WiFi Signal Strength: If the thermostat is on the edge of your WiFi range, it will constantly cycle the WiFi radio to search for a signal. This creates intermittent power spikes that can crash the memory module. Install a WiFi extender halfway between the router and the thermostat to stabilize the connection.
• Inspect for Loose Terminals: Turn off the breaker and tug gently on each wire in the terminal block. A loose R or C wire can cause "micro-breaks" in power that are too fast to turn the screen off but long enough to wipe the volatile memory. Re-seat and tighten all screws.

Heads Up

• Battery Warning: Always use name-brand Alkaline batteries. Zinc-carbon batteries lack the discharge curve necessary to maintain the GEO's WiFi chip during power transitions.
• C-Wire Necessity: While the GEO is marketed as compatible with some 4-wire systems, the WiFi functionality and schedule memory are significantly more stable with a dedicated C-wire.
• Voltage Spike Risk: Never touch the R and C wires together while the power is on, as this will blow the 3-amp or 5-amp fuse on your furnace control board instantly.
• Scheduling Tip: When setting your schedule, ensure you have a clear "Wake," "Leave," "Return," and "Sleep" period defined. Leaving any period blank can sometimes cause the software to glitch and reset to defaults.