Display shows H1, unit does not heat, outdoor unit may be in defrost

Note: H1 on many Tosot heat pump models indicates defrost mode, not a fault.

• Observe operation: During H1, the outdoor unit may stop the fan and reverse cycle to melt ice. This can last several minutes.
• Check for excessive ice: If the outdoor coil is completely encased in ice, turn off the unit and gently remove loose ice. Do not use sharp tools.
• Ensure airflow: Clear snow, leaves, or obstructions around the outdoor unit.
• If H1 is constant and no heating: The defrost sensor or control may be faulty. A technician should check sensors and defrost logic.