Leave it to the rookie!!
I went to an emergency call tonight on a reach in cooler at a well known restaurant. When I arrived I checked my notes and saw the new guy was just there this morning. The notes said added R-134a and unit was fine. I found cooler at 44 degrees on arrival. Checked my pressures and well overcharged, checked condenser coils, stopped up like no tomorrow. After a cleaning the coil and adjusting my charge back to where it was supposed to, I found temp control set on 40. REALLY? Was he thinking dump in some R-134a and raise the temp, that should do it. Even if the charge was right and the coils washed he was setting himself for failure. Please new comers, if you don't know, please ask someone.
2nd generation commercial technician