Winterization of mitsubishi ductless air conditioner

the thermostat is powered by the unit or batteries if batteries they may be dead if the unit you need to check fuses outside at unit or reset breaker outside depending on age of installation

Why does my heat pump ice up in Winter?
Heat pumps naturally ice-up in the winter. It is normal for the entire coil to be covered in a white frost and even light ice, during cold weather conditions. However, it is bad for the entire unit to be encased in ice. This indicates ductless heat pump problems which should be addressed quickly to save energy and avoid serious damage to your ductless unit. These systems should periodically go into a defrost cycle. This keeps the unit running efficiently. If the coils are blocked by ice, proper heat transfer between the coil and the outside air will not occur.
How does the defrost mode work?
When the mini split heat pump goes into defrost, the reversing valve inside of the outdoor unit is energized, switching the system from heat to the air conditioning mode. The outdoor coil becomes the hot, the indoor coil becomes cold, and both - the outdoor and indoor fans shut off. This allows the outdoor coil to melt accumulated ice. When the built-in micro-computer analyzes that all ice have been melted, the heat pump heating system goes back to heating mode.
A cloud of water vapor may be seen rising over the outdoor unit and a "whoosh" sound can be heard as the refrigerant reverses direction. The entire process usually takes up to 10 minutes (depending on conditions).
How often does the system goes into defrost mode?
Ductless mini-split heat pumps have different ways of determining when to go into defrost. The built-in microcomputer determines outdoor temperature, refrigerant pressures, and several other factors. In colder temperatures the system will go into defrost more often than in warmer.
If a ductless mini split heat pump is severely iced-up in the winter it is possible that it isn't defrosting (though there could be many other causes). Let the manufacturer certified technician check your system

Please check your indoor motor's mechanism is faulty. Or capacitor(condenser) of fan motor is weak. Replace it.

I have used mine for many years without covering in the winter (in mid-atlantic climate with moderate winters).

Is the compressor running? is the outside unit clean and free from debris? does this unit work in the heating mode during the winter, and is it still capable of that now.

pop out drain plug heat up pan with heat gun to melt ice

usually a cover goes on the outside but TOO HIGH your super needs a boot in the ****.open the front grill and put a towel or hand towel over it close cover back.that should help till your super gets a ladder

Yes this will recycle the room and can be cover outside if it is not a heat pump and will use elec heat strips to heat. As long as it is tilled toward the back the water will run out the back without a drain kit there should also be a drain hole in the bottom.