Amana heat pump in heating mode runs but delivers little or no warm air; auxiliary heat may not engage.

Safety first: Turn off power at both indoor and outdoor units before opening panels.

Steps to improve heating performance:

• Check outdoor coil: Inspect for heavy ice buildup. If present, the defrost system may be malfunctioning (see defrost sensor and board).
• Verify reversing valve operation: Listen for a distinct whoosh when switching between heat and cool. Lack of change may indicate a stuck valve or control issue.
• Aux heat: For systems with electric heat strips, check breakers and fuses for the heat kit. A technician should test strip elements and relays.
• Refrigerant issues: Low charge or restrictions require a licensed technician to diagnose and repair.

Do not attempt to manually force the reversing valve; it is controlled electrically and by system pressure.