my schedule keeps disappearing or resetting to default on its own. why won't it save my changes?

Diagnosis

The Honeywell Home RTH9585WF relies on a constant stream of 24VAC power to maintain its volatile memory and sync with the Total Connect Home (TCH) cloud servers. When your schedule disappears or reverts to factory defaults, it is almost always due to "power cycling" or "brownouts." If the thermostat is not receiving consistent power via a dedicated C-wire (Common wire), it attempts to "power steal" from the R or Rc wires. During high-demand cycles (like when the furnace blower kicks in), the voltage can drop just enough to trigger a soft reboot. Because the RTH9585WF stores its active schedule in a temporary cache before syncing it to the cloud, a sudden power loss during a write-cycle corrupts the local memory. When the unit reboots, it fails the checksum validation for the user schedule and defaults back to the factory "Standard" template. You can confirm this by checking if the thermostat screen flickers or if the WiFi icon disappears momentarily when the HVAC system engages; this indicates a voltage drop that is wiping your settings.

How to Fix It

To stop the schedule from resetting, you must ensure a stable 24V power supply and force a hard sync between the hardware and the cloud server. Follow these steps exactly:

1. Verify C-Wire Continuity: Pull the thermostat faceplate off the wall. Locate the C terminal. If no wire is connected, or if a wire is loosely capped, your unit is power-stealing and will continue to reset. If a wire is present, use a multimeter to test the voltage between R and C; it should read between 24V and 28V AC.
2. Perform a Hard Power Cycle: Go to your circuit breaker panel and flip the switch for your HVAC system to "OFF" for exactly 60 seconds. This clears the corrupted cache in the thermostat's internal memory.
3. Clear Local Schedule: Power the system back on. On the thermostat screen, go to Menu &rsa; Schedule. Select "Clear All" to wipe the corrupted local data.
4. Reconfigure via the App: Do not program the schedule on the wall unit. Open the Total Connect Home app on your smartphone. Navigate to the Schedule tab and enter your desired temperatures and time slots here.
5. Force Sync: Once the app schedule is saved, go to the thermostat wall unit, enter the Menu, and select "Sync." This pushes the cloud-based schedule into the local hardware memory, ensuring that even if the WiFi drops, the schedule remains locked in.

If That Didn't Work

• Install a C-Wire Adapter: If your home lacks a C-wire, do not rely on power-stealing. Install a Honeywell C-Wire Adapter (Part #CWE-144) at the furnace control board. This converts the G-wire or a spare wire into a dedicated power source, preventing the voltage drops that cause memory loss.
• Check the Furnace Transformer: A failing 24V transformer in your furnace can produce "dirty" power with significant ripples. If the transformer is overheating or humming, it can cause the RTH9585WF to reboot randomly. Replace the transformer if it outputs less than 22VAC under load.
• Update Firmware via Reset: If the schedule still resets, the firmware may be hung. Press and hold the "Reset" button (if available on your specific revision) or remove the unit from the wall and remove the backup batteries for 10 minutes to force a full firmware re-initialization.
• Check for "Adaptive Intelligent Recovery": Ensure "Adaptive Recovery" is turned off in the settings. Sometimes users mistake the thermostat's attempt to reach a temperature *early* for a schedule change, making it seem like the settings have reverted.

Heads Up

• Avoid Battery-Only Operation: Never rely on batteries for the RTH9585WF if you have a C-wire option; batteries are for emergency backup, not primary power, and can lead to erratic WiFi behavior.
• Avoid Frequent Manual Overrides: Excessive manual temperature changes during a scheduled period can sometimes confuse the "Hold" logic, making it appear as though the schedule has disappeared.
• Check WiFi Signal Strength: A weak signal (below -70dBm) can cause the thermostat to struggle to sync with the TCH server, leading to "ghost" settings where the app shows one thing and the wall unit shows another.
• Inspect Wire Gauges: Ensure you are using 18-gauge thermostat wire. Using thinner wire over long distances causes voltage drops that trigger the memory resets described above.