Hi Sirs,
I've just done a dehumidifier test. The frost is serious at the place of distributor outlet tubes of DX cooling coil. The pressure before distributor is 5 bar(R22) gauge pressure which should not cause frost. Suction temp is too high 20C,the dischange pressure is 14bar gauge.I think the distributor is with some problem. Blocked or large pressure loss. how do you think?

rgds
LC