Evaporator icing up due to high TD, I use the Testo 550 bluetooth

I adjust the expansion valve to get it to evenly feed the evaporator coil. I use my new Testo with blue tooth.
High humidity(meat coolers) 10 degrees
low humidity (soda/beer coolers) 15 degrees
low temp (freezers) 1-3 degrees
AC - dry 15-24 degrees
Allied Refrigeration 440-823-5720
Cleveland , Ohio