A common problem
In heating mode, a unit may briefly delay warm airflow at start-up. If the room stays cold, check the settings and note any error code.
Limit checks to basic user actions:
Select heating mode (sun) and set a temperature above the current room temperature.
Wait a few minutes after start-up; some models delay the fan while warming up.
Check and clean filters as described in the manual and keep the airflow clear.
In cold, damp weather the outdoor unit may periodically defrost. Do not remove ice with tools.
Request service if there is still no heat after basic checks, the unit stops repeatedly, an error code appears or the outdoor unit builds up ice and does not defrost.
Do not chip away ice or dismantle the unit. If you smell burning or a breaker trips, disconnect power only if safe and contact a technician.
A better project. A cleaner installation. Fewer unforeseen costs during construction.
