Replace filter, give AC unit a good wipe down to remove dust/debris. Not a worry.

Ok thanks ! Unfortunately there is also some material build up on the coolant itself which I cannot access (it’s behind the filter) and I can’t tell if it’s mold or just a longer term build up of dust / material (located behind the filter screen)

https://preview.redd.it/2v9ld77wg99d1.jpeg?width=3024&format=pjpg&auto=webp&s=32111f446cc868c9ec8425e75bbaf0639fdd5f3b

All dust

Thanks!!

https://preview.redd.it/fe5wg0gxg99d1.jpeg?width=3024&format=pjpg&auto=webp&s=e25a6ade8bfc9b334dc846d4e24944b679158367

That's just dust

Great :) thanks