Can you add refrigerant to a portable air conditioner?

Question edited to add a maker, and spelling 'portatable' to 'portable' x 2.

Take into a local refrigeration company. It is probably the control board.

Add a pressure tap if there is no access to the refrigerant loop & check pressures... sounds like it is a little low on refrigerant.

not exactly DIY you are supposed to be a qualified air con repairer
you have to vacuum pump the system dry
check for leaks
then with the right gas and pressure guages add new coolant

Google this question

The compressor picks up the gas that is bringing the heat removed from the house to be compressed to liquid and cooled in the condenser coil When running the compressor is very hot. When the freon is low the compressor will be cooler because it doesn't have as much heat to compress. To add freon you must add a service valve to the low pressure line.

Hi,
Here is a tip that I wrote about how to add refrigerant to a air conditioner orcooling system

How to add Freon to a Air Conditioner or Refrigeration System

heatman101

Hello my name is Heath it will be my pleasure to assist you. If you have to add refrigerant then there is a leak in the unit and it would have to be leak check fixed evacuated and then recharged.

you proably do need a piercing valve as those units usualy have no acces to the refrigerant. be carefull on how you do that the best way is to braze a fitting on and pull a vacuum then charge. most piercing valves will end up leaking on you down the road

they all take refrigerant but there are other things like dirty filter or condensor coils that will cause the same problem