Is your discharge line Hot? If not climb in the cases and try to figure out which valve is overfeeding. Also check out the evap fan blades. Alot of guys end up throwing a little 3incher on when it needs a 5.5".:D
The ones I installed for them did not have EPR valves. They also used transflow blowers not standard fans. Agree that w/ epr they would have worked much better but I was not the engineer and they wanted to keep cost low, didn't seem to consider future service cost.
I hate set ups on singles with multiple loads and then not provide anything for capacity reduction.
I've been working on denny's freezer/fridge drawers for a couple years now. always a pain in the arse. The one im working on currantly has 3 compressors on the roof. 2 of the compressors are running multiple fridge drawers. About 4 a peice. The other compressoor is running just one freezer drawer. All 3 compressors have liquid acumilators. the freezer drawer system has a suction line acumilator also. They all have pressure controls to cut out on pressure drop. All the fan coil's have silinoids. the fridge drawers have t-stats inside the drawer units. the freezer draw has no t-stat and is controlled by the pressure control that shuts the copressor off when the unit dropes to a pressure on the low side that correlates to the temp inside the freezer. They all have defrost controls.
I had the freezer drawer down to 5* f threw last fall and winter. now that it is warming up outside it is having problems again. started by cleaning the coils outside that were filthy. temp still not low enough. now im back to counting turns on the expantion valve and playin with the charge. I hate these units.