Ac in heat mode

Hi guys,

I live in Sharjah with free ac in the building. Do you know if I can use the ac in heat mode ? MIt's pretty cold in the apartment (around 19 degree) I would like to heat it up a little bit. I tried to use ac and set 31 degrees but it does not seem to work... I try the 3 modes available...

Do you manage to use ac in heat mode ?