split AC -outside heat exchanger iced

[Lc_shi]

hi sirs
one split AC operating around -4~4C(outside temp) and outside HX frost serious and more and more frost on it as it's runing. what's the reason? defrost controller issue/gas leak/ac capacity is small to meet the conditioned space or others?

what your idea? pls help. thx

regards
LC:confused: :)

[Brian_UK]

LC, could be any of the above..

What make/model is the machine, most heat pumps can deal with -4°C so that should be OK. If the defrost controller is at fault then yes the coil will keep freezing.

More info required please.

[Lc_shi]

Chinese Hisense, I'm not sure if you're familiar with it. thanks

rgds
LC