Hey guys ive been working on a site which has an old freezer unit that has been reinstalled. It runs on R404A. Anyway ive noticed the installation company has under sized the liquid line. The original size was 1/2 inc h and they have installed 3/8. The problem is this freezer is running at low pressures when the temp inside the freezer is -6 my back pressure is 40 psi. This does not match with my p.t chart for r404a. The compressor is getting nice sweat back untill about -10 degrees C then the suction line starts to ice up. The freezer takes a really long time to get down to temp and stops at about -16 when i need it at -20 . Upon inspecting the condensing unit ive found that the compressor is a scroll compressor that has a liquid injection line running back to the compressor, This line has a solenoid valave on it. I did a bit of research and found these lines are for cooling the compressor.There are no sensors to set this valve up as i understand it there should be a temp sensor on the head of trhe compressors that opens and closes this valave. I intend to leave this disconnected. I am 100% sure that the unit is not short on refrigerant and there are no nnon condenseables in the system as ive personally vacuumed and charged system tot a full sight glass. i cant really check superheats as the system is not down to desired temp. I guess my question is will this undersized liquidline be causing my low suction pressures due to a pressure drop in the liquid line as its smaller.