The AC has been retrofitted to RJ134A.
Seems to work fine when the cabin is cool (e.g. after overnight) and at higher engine speeds, approximately over 3K rpm. After warm-up at lower speeds and idle it does not work, though the compressor seems to be engaged. Also the aux fan opeartion is intermittent, engages sometimes after the elctro-magnetic fan and sometimes not at all.
Any help is appreciated. Thanks.