Hello my friends first time so i am a little green at this. Here is my issue wondering if u can offer any help. Tempatures inside box was only coming out at about 10 degrees. have a walk in freeze on second floor of building compressor is a Copland cs14k6e-pfv-270. Txv is a danfoss model Tey268z3285 -40 r502. Box size is about 6 feet by 8. Been there for awhile. Originally had r502 replaced to 408 refrigerant and changed filter tempature were coming out -20 and thought done. Well same issue. Box was still only at about 10 F degrees two days after. So I checked my superheat ambient tempature was at 70 f degrees. Low side pressure at 40 psi line temp at 25 so superheat is ten. Good . So when I put temp at front of evap fan I get -23 f Return temp is 2f degrees. Nothing blocked coils are clean at cond and evap. Pressure at cond low side 45 high side 165 any clues checked defrost timer in case it was getting stuck nothin.

Notice recent exhaust fan installed i asked for what they said to keep air around both walk ins dry they also had handyman seal of all corners due to mold build up. Was running this way for several months told them to shut this off for time being don't want pull in hotter air around walk ins. But it is solid 4 inch walls built up and tight.