Thermostat displays E12 and will not complete configuration for heat pump or dual fuel system

Safety first: Turn off power to the indoor and outdoor units at the breaker before changing wiring.

• Step 1 – Confirm system type: Verify whether your Amana system is a heat pump or a conventional AC with gas furnace. This determines how the O/B terminal should be configured.
• Step 2 – Check thermostat settings: In the installer setup menu, ensure the O/B setting matches the Amana heat pump requirements (O or B energized in cooling, depending on model). Refer to the Amana equipment manual.
• Step 3 – Inspect O/B wiring: At the thermostat, confirm the O/B wire is connected to the correct terminal. At the Amana outdoor unit and indoor control board, verify the same conductor is landed on the reversing valve terminal.
• Step 4 – Test operation: After correcting settings and wiring, restore power and test heating and cooling modes. The thermostat should clear E12 once it detects proper response from the reversing valve circuit.

When to call a professional: If you are unsure of your system type or reversing valve behavior, have an HVAC technician configure the thermostat and verify Amana heat pump wiring.