Simply set your desired temperature and allow the compressor to either speed up or slow down to maintain that temperature. Cool. The cool mode switches on the compressor to produce cool air into your space. Once the air conditioning unit senses it has reached the desired temperature, the compressor switches off and the fan will run. A low refrigerant level may be the cause of your Mitsubishi air conditioner not cooling as expected. When the refrigerant level in the compressor is low, it cannot cool air fast enough. This can cause the coils to freeze. Furthermore, the heat will build up and affect the coils if the air conditioner runs continuously. Jul 1, 2018. #1. I have had my minisplit for several years and normally used it in cooling mode. WIth the recent hot humid spell I have been running in in dehumidification mode.It still cools the house but it really drops the humidity. I am impressed, I have the fan set to automatic and once I knock down the initial humidity it just idles along stop the air conditioner and disconnect the power plug or turn the breaker OFF. • A continued operation in the abnormal state may cause a malfunc-tion, fi re, or electric shock. In this case, consult your dealer. When the air conditioner does not cool or heat, there is a pos-sibility of refrigerant leakage. In this case, consult your dealer. Reverse-cycle air conditioning is a system that uses reverse-cycle technology to both heat and cool your home. It’s essentially two systems in one, and allows you to reverse the refrigeration cycle of your AC unit (hence the name ‘reverse cycle’) to produce heat instead of cooling. When the reverse cycle unit is in cooling mode, it works Quiet Mode in AC /Calm mode in AC /Silent mode in AC. This mode will lower the noise levels of your AC (it will slow the fan so fan speed will be very low) to the lowest possible while still cooling the space. The downside is the cooling efficiency is not that good when in silent mode. I should add that Quiet Mode is the same as Sleep/Rest mode Locate this switch and make sure it is in the “Off” position. Step 2: Wait for a Few Minutes. After turning off the main power switch, give the unit a few minutes to completely power down. This will allow the system to reset and clear any residual electrical charge. Step 3: Turn On the Main Power Switch. Heat Pump Troubleshooting Problem #3: BLOWING COLD IN HEAT MODE. First of all, just check and make sure your unit was not accidentally switched to a/c mode. Next, check your outdoor unit is not iced over (see Heat Pump Troubleshooting Problem #1). If not, your system may have a valve problem, a refrigerant charge issue, or a compressor problem. RzO0VL.