Amana heat pump in heating mode shows H1; outdoor unit may defrost frequently or stop heating.

Safety first: Shut off power at the outdoor disconnect. Coils may be icy and slippery; use caution.

Steps to address H1 (defrost fault):

• Inspect outdoor coil: Check for heavy frost or ice buildup. Light frost is normal; solid ice indicates a defrost issue.
• Locate defrost sensor: Find the thermistor clipped to the outdoor coil tubing. Ensure it is firmly attached and not dangling.
• Test sensor: Disconnect and measure resistance; compare to the Amana chart for the current coil temperature. Replace if out of spec.
• Check defrost board: Inspect the defrost control board for burnt components or water damage. Replace if visibly damaged or if H1 persists with a good sensor.

Defrost control issues can reduce heating capacity significantly; timely repair prevents compressor stress.