Thermostat display is completely blank and system does not run

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

• Step 1 – Check other equipment: See if the furnace/air handler status lights are on. If the indoor unit has no power, check the breaker and service switch.
• Step 2 – Inspect thermostat mounting: Gently pull the thermostat off the wall plate and reseat it firmly to ensure good contact.
• Step 3 – Check low-voltage fuse: Open the Amana unit’s control compartment and locate the small blade fuse on the control board. Replace it with the same rating if blown. If it blows again, there is a short in the thermostat or accessory wiring.
• Step 4 – Measure 24V (advanced): With power on, measure between R and C at the control board. If no voltage is present, the transformer or board is faulty and requires professional replacement.
• Step 5 – Inspect thermostat cable: Look for obvious damage where the thermostat cable enters the furnace or wall. If damaged, the cable must be replaced.

When to call a professional: If the fuse repeatedly blows or there is no 24V at the control board, contact an HVAC technician to service the Amana equipment.