1. Turn off the cassette fan coil unit air conditioner with the remote control, remove the ceiling around the air conditioner, cover the floor below the air conditioner with paper, and isolate the dirt in the working area.
2. Pull the lock to remove the filter screen, clean and disinfect it with cleaning agent, and then dry it in the air.
3. Remove the four corner blocks of the air return outlet of cassette fan coil unit. Screw the hook screws of the return air outlet at the four corners of the block to the loosest position, unplug the connection between the return air block and the control power supply, remove the return air outlet and clean and disinfect it.
4. Close the cooling water inlet and return valves. Remove the cover plate on the control circuit board.
5. Remove the power cord and electric valve control line from the control circuit board, and make insulation bandage. Remove the control lines of water pump motor and scavenging motor from the control circuit board.
6. Unplug the signal wire of the temperature probe from the control circuit board.
7. Remove the fixing bolts at the four corners of the water receiving tray and remove the water receiving tray.
8. Clean the water receiving tray. Because there is a circuit board on the water receiving tray, the dirt can only be cleaned by spraying detergent with rags, and then sprayed with disinfectant. Finally, wipe it clean with a rag and clean water.
9. Unscrew the fixing nut of the volute wind wheel and remove the wind wheel.
10. After removing the volute wind wheel, clean it with cleaning agent and dry it. After the wind wheel is removed, the coil heat exchange fins are exposed completely
11. Clean the coil fins, spray the air conditioner cleaning agent on the fins with a watering can, and brush them down from the upper part of the fins with a stiff brush after five minutes.
12. After brushing, rinse with a water gun (note that the water container should be used to receive water below). After washing, disinfect with disinfectant, and then blow off the moisture and dirt inside the fins with compressed air.

Note: There is a lot of dust. Please wear a mask for operation. The power cord of air conditioner is disassembled with electricity, so please be very careful, and wrap one with insulating tape to prevent electric shock. There are many plugs in the control line, so it should be marked when pulling out to avoid the loss caused by inserting the wrong plug or connecting the wrong line during installation.