There are plenty of of YT videos on removing the blower wheel, but I would caution against it. As the units age the evaporator coil is very susceptible to being easily damaged and cause of refrigerant leaks while trying to remove the blower wheel. The coil and blower can be easily cleaned without disassembly using the Port A Blaster low pressure sprayer along with a spit AC waterproof bag.

Depends on the unit, its location, water access, install quality, ect. We are a commercial outfit, we don't have a flat rate for a mini-split. It takes about 2 hours plus cleaners to do an indoor head like this once the ladder is set up and we can get the unit apart. If the unit has more than one head we can usually get the other heads done a little faster once all the cleaning stuff is setup.

I would do the outdoor ever year at least, if your cotton wood is bad you might need more than once a year. For the indoor It depends on the environment they are in, The plastic blower wheels in high wall mini-spits like this tend to hold onto dirt really well. When they are in a clean space like a bedroom they can go longer between cleanings but if they are in garden, retail space or anywhere the dust is made of fine/small particles they can get dirty really fast. The best answer is to pay attention to your unit, check and clean the filters once a month, as they are the only line of defense, visually check the coils while you are in there. your coil be pretty clean all the time no dirt parches in the corner and never should it look like a lint trap. Next shine a flash light under the blade dampers with the unit off and you can see the blower wheel like we did in the beginning of this video. Fan blades are like snow shovels, once they have a layer of build up on them they loose their shape and move less volume, bigger the build up the less air it will move, so if your airflow is starting to get weaker its likely time. Also if the mini-split starts leaking water all the sudden, the drain pan is likely plugged up and it needs to be cleaned.

@@mechanicalenvironments excellent advice 👍 thankyou

No, the refrigerant lines do not need to be disconnected. Definitely turn off the power to the outdoor unit (as it powers the indoor unit) you really need to take it apart to get the wheel out. Each unit is a little bit different but its gonna be a handful of screws and some hidden plastic clips to get down to the wheel, patience is key. Wheel set screws are sometimes inside the wheel and sometimes next to the wheel under another cover. Often the coil can lift up on the opposite side of the motor to allow the wheel to escape once the set screw is loose.

It looks and feels organic, and it looks like it grew in place, but we’re not experts in identifying mold. It definitely could be.

After one summer I see a lot like that or worse

I've seen units like this after 1 year after a brand new install, and I've also seen units that haven't been maintenanced in a few years that aren't actually that dirty. It really depends on the cleanliness of the environment, where the unit is located (is there a lot of foot traffic? Is it in a common area near a door that opens often?), and how often they actually use the system. Hell I have customers that get these installed, call you for maintenance every year only to find it pretty damn clean and they're like, "Yeah I actually rarely use it" those customers are typically the elderly that prefer to live like lizards under a heat lamp ahaha.

This unit has a manufacture date for 2 years ago. The plastic blower wheels in high wall mini-spits like this tend to hold onto dirt really well. When they are in a clean space like a bedroom they can go longer between cleanings but if they are in garden, retail space or anywhere the dust is made of fine/small particles they can get dirty really fast.