Flashing 'fl'

FL errors on an LG air conditioner means that there was recently a power failure which caused the unit to turn off. This is very common, especially in areas where a lot of power outages occur.

unplug and let it set for about 30 minutes and it should be fine

Everything I found when trying to fix this was absolutely useless including the LG manual for this device (they don't even give you an anatomy of the device), so I'll post how I fixed it if anyone is having trouble still. I had the same issue as posted above, it was flashing "FL" and turning off after about 4 seconds of running, even though I had emptied the reservoir at the bottom. The thing is that my reservoir wasn't actually empty, it was just clogged full of gunk. The real water reservoir is located around the middle of the unit. The bottom area is just a pan area for water to collect that runs out of the main reservoir. Try this:

1. Take the back off of the unit by taking out the 10 or so screws (there's one hidden behind the back air filter after you take that out). Slide the circuit board at the top of the unit behind the control panel off and wrap it inside a plastic bag or something similar to keep it from getting wet.

2. Around the middle-back of the unit there is a white spout that you can also drain from, this spout leads into the main water reservoir. Take the 2 screws holding this spout off.

3. Get a garden hose with a jet stream or anything similar and jet water at high pressure into the reservoir to unclog the gunk. It took me about four separate 5-10 minute sessions to finally get all the gunk out. As you're spraying the gunk clogging the reservoir's drain should come out along with any water trapped behind it.

4. Repeat 3 if you're still getting FL error after unclogging the reservoir. Like I said it took me multiple tries.

Hopefully this will fix your issue, if not then perhaps a sensor is just bad (what I thought initially, but turned out not to be the case). If you do get it working again it would be good to set up a drain system to prevent this from happening again. I currently use 3/8" vinyl tubing with some plumbers tape that runs into a bucket that gets emptied via a water pump that takes the water out of my window. You can also run a line straight into a drain if you have one nearby, or simply run the water into a bucket or other container and empty it however often you have to.