Thermostat shows E11 and cannot detect or control the Amana furnace/air handler

Safety first: Turn off power to the furnace/air handler at the breaker before opening panels or touching wiring.

• Step 1 – Check thermostat display: If the thermostat is completely blank, it may not be receiving 24V power. Proceed to check R and C wiring.
• Step 2 – Inspect wiring at thermostat: Ensure R and C wires are firmly connected and not broken. Gently tug each wire to confirm it is secure.
• Step 3 – Inspect wiring at furnace/air handler: Open the Amana unit and locate the control board. Verify that the thermostat cable is connected to the R, C, Y, W, G, etc. terminals. Tighten any loose screws.
• Step 4 – Check low-voltage fuse: Look for a small automotive-style blade fuse (typically 3–5A) on the Amana control board. If it is blown, replace it with the same rating. If it blows again immediately, there is a short in the thermostat wiring that must be found and repaired.
• Step 5 – Measure voltage: With power on, measure between R and C at the control board. If there is no 24V, the transformer or board is faulty and needs professional service.

When to call a professional: If the fuse continues to blow or there is no 24V at the control board, contact an HVAC technician to diagnose the Amana control board and transformer.