Mysa Smart Thermostat only shows Off when the HVAC configuration code is missing

Overview

If a Mysa Smart Thermostat powers on but only shows Off, will not switch to Heat, or does not show normal temperature controls after setup, the HVAC configuration code may not have been saved correctly.

Why this happens

The configuration code tells Mysa what type of HVAC equipment is connected. If no valid code is assigned, the thermostat may not unlock normal heating controls and may only show Off.

What to check

• Confirm the correct HVAC configuration code for the system using the Mysa app setup flow or Mysa Code Finder.

• Check the thermostat configuration in internal tools, if available, to confirm whether the code is present or blank.

• If the app rejected the correct code during setup, have the customer manually enter the code on the thermostat device, or reconnect the thermostat to the Mysa app and enter the code again.

• After the code is saved, confirm that Heat mode and temperature controls are available.

When to escalate

If the correct code is entered and saved but Heat mode still does not appear, or if the app continues to reject a valid code, escalate for software or installation troubleshooting. Include the system type, wiring terminals used, the intended configuration code, and the exact setup step where the code fails.