Thermoking V-200 Unit

[loja.manuel]

Hi,
Working on a clients V-200 thermoking unit. R404A at 2 Kg in suction,
but half the compressor and suction tube frost's. Thought it would be excessive gas.
Took out gas to 1,5 Kg and the same problem persists. Even at 1,2 Kg the same problem. It doesnt flow cold air threw evap.
Expansion gets warm but not hot like should be. Pressure variates between 2kg and 1,2 Kg. Is this normal after putting a new belt?
Is the R404A mixed with air that it doesnt cool?

Sorry for bad english.

[loja.manuel]

Forgot to say, this happens with stand-by electrical compressor. Road compressor works fine.