Indoor unit of Hitachi split AC appears red, green & yellow at the time switching on through stabilizer without any beep sound which was not happening earlier. The red & green light is off with a beep sound after few 2-3 seconds and yellow light remains on. This is happening every time when stabilizer switch is made on after 3-4 minutes but not immediately off & on. But the functioning of AC is O.K i.e cooling, fan and other remote control activities. After some hours while AC is on & working O.K i.e. cooling according to temp. set, all of a sudden red light appears and there is beeping sound which continues for few minutes and after that red light is off. There seems to be some disturbance in stabilizer also during that period as some sound comes out from stabilizer. I am not sure as I wake up on hearing the beep sound & red light at least 3-4 hours continuous AC is on at night. AC again continues working O.K. after the red light is off. The trouble does not seems to be serious one but it is a new one to me out of 3 Split AC I have. I don't know about the seriousness of the fault. Kindly advise me accordingly.

Heating & Cooling - Hitachi