Model M1A 12' long about 48' total

5hp compressor running 409a gas

I have a problem that none of the local repair tech are able to figure out. Even called in tech that KysorWarren recommended and still nothing.

Problem are 2 front -
Can not get the product temp below 40 degrees.
Evaporator is freezing up within 2 days of getting all the ice off it.

This unit has been in this building almost 25 years.

there are 6 - 25 min defrost cycle put in by the last tech. who also adjusted the superheat at each section of the open single deck meat case. he also checked the humidity in the store and it was around 45. there are no ducts blowing air on the case. the store temp does go above 75 to maybe 78.

the thermosatat is hooked up to a solenoid that is on the return line and that's all the controls the configuration.

the liquid line is cold and has a little frost right below the case i am not sure what else to do. Have been spending a lot of money and have no results.

I have to get the product below 40. and get the ice off the coils.

anyone able to repair this i am at zipcode 31021