Branch Box LED 402 blinks 8 times & LED 404 is lit — Indoor Unit B, EEV control error.

What does LED 402 (8) / LED 404 Lit mean?

LED 402 flashes eight times and LED 404 is lit, indicating an error with the Electronic Expansion Valve (EEV) control for Indoor Unit B.

• Malfunctioning EEV.
• Wiring issue with the EEV control.
• Malfunctioning Indoor Unit B PCB.

Click steps to track your progress.

1. 1

   Reset the power to Indoor Unit B and the branch box by cycling their circuit breakers.

2. 2

   If comfortable, visually inspect the EEV for Indoor Unit B for any obvious damage or loose connections.

3. 3

   If the problem persists, a technician should inspect the EEV and its control circuit for proper operation.