It is normal.
Once you start heating, there will be cold wind from the outdoor unit as much as hot wind from the indoor unit, thus the rear of the outdoor unit will accumulate frost on it.
On a rainy or snowy day with high humidity, more frosts will be formed and the cycle operates to detect the amount of frost for automatic defrosting, and meanwhile, heating is temporarily paused and the product says preheating/defrost.
As the defrost cycle starts, the outdoor unit will generate hot wind to automatically remove frost, while frost is melting, the out door unit will generate steam or discharge water to the floor.
Frost on the outdoor unit
During defrosting operation
Defrosting completed
This guide was created for all models, so the images or content may be different from your product.
