Thermostat displays E8 and may shut down compressor operation to protect equipment

Safety first: Turn off power at the breaker before opening furnace/air handler panels. Use caution around line-voltage components.

• Step 1 – Check home power: Verify there are no ongoing power issues in the home (dimming lights, tripped breakers). Resolve any utility or panel problems first.
• Step 2 – Inspect thermostat connections: Remove the thermostat and ensure R and C wires are firmly connected and not corroded. Reseat the thermostat on the sub-base.
• Step 3 – Measure 24V (advanced): With power on and using a multimeter, measure between R and C at the thermostat and at the Amana control board. Readings significantly below 24 VAC (e.g., under 18 VAC) indicate a low-voltage problem.
• Step 4 – Inspect transformer and wiring: At the furnace/air handler, inspect the low-voltage transformer and its connections. Look for burnt smells, discoloration, or loose wires. Tighten connections; if the transformer is hot or humming loudly, it may be failing and should be replaced.
• Step 5 – Clear error: After correcting voltage issues, power cycle the system. The thermostat should clear E8 automatically once stable voltage is detected.

When to call a professional: Low-voltage transformer or control board replacement on Amana equipment should be performed by a qualified HVAC technician.