Indoor unit displays H1 and heating is temporarily unavailable.

Note: H1 on many MrCool heat pump systems indicates a normal defrost operation, not a fault.

Steps:

• Wait: Allow 5–15 minutes for the defrost cycle to complete. The indoor fan may slow or stop during this time.
• Check outdoor unit: Confirm that the outdoor coil is frosted and that steam may be visible as ice melts. This is normal.

If H1 is constant: If the unit stays in H1 and never returns to heating, the defrost sensor or outdoor PCB may be faulty and should be checked by a technician.