Diagnosis
This indicates a complete loss of power to the main control board. The most common points of failure are the user interface touchpad or the main control's internal fuse.
How to Fix It
Verify the electrical connection. Ensure the unit is plugged in securely or the junction box connections are tight. Check the household circuit breaker and GFCI outlet if applicable. If power is confirmed, the issue is internal. The user interface on this model is a common failure point.
If That Didn't Work
A failed thermal fuse on the main control board or a faulty power supply component will cause this symptom. This requires board-level diagnostics or replacement of the main control.
Heads Up
Before replacing the user interface, disconnect power for 5 minutes. This can sometimes reset a locked control. If it powers on after, a hard reset was the fix.