About a week after the install, the thermostat started to show "System Malfunction" message. The tech told me to press and hold the "Advanced" setup button to see the error. I did and it showed error 47 "No 230V to Unit". I called the tech and it turned out that the wire connections was not installed tightly in the external breaker box (mounted next to the air conditioner compressor unit). Hmm... bad installation? Not a good omen!
A few week later I noted water running out of the overflow water tray. I decided to go up to the attic and take this video:
I called Chas Roberts and they came out again with a 3 man crew. It turned out that the water pan cracked from "bad installation" (again!) of the drain pipe. They had to re-mounted the unit and replaced the pan.