The Lamp Room

https://www.youtube.com/watch?v=PfqtNdo9Sos
https://www.youtube.com/watch?v=Dw8__kw63D4
When the A/C working on heating, and the compressor not working because the room reached to the temperature set on its remote control, the fan of the indoor unit, instead of stop spinning completely, continue to spin, but at very low speed so air don't exits from the indoor unit.
Why this is happening?

There may be reasons why the AC unit design requires it to keep spinning at a minimum speed

One reason i can think of is the fact that to heat the room to say 22C, the radiator in the unit have significantly higher temperatures, possibly heading to 100C

Without air movement, the radiator would heat to a similar temperatutre the plastic parts of the unit that form the air duct around it, and plastics don't last long at such tempertures. (They dont melt yet, but they do become brittle and may deform slowly)

Keeping the air moving a little prevents the temperature of the duct from reaching the same temperature as the radiator



Or it does slow down in the end ?

Being a fan, the mechanical load on it from air resistance depends on the fan speed squared. This means that at slow speeds the air resistance becomes very low. Then the fan can keep going by inertia for quite a while with the motor off

The fan always spinning at very slow speed when the A/C is at a delay at heating. It never stopping at this period.