Hi i have some questions related to refrigeration and compressor . i work in a company and we have sabroe 128HM compressors for cold storage.

1: whats the difference between suction temperature and suction super heat, also discharge temp and super heat.

2: there is one room which give problems , set temp is 4'C while room temp stay above 6'C. there's anothor temp mention in the PLC display "duct temp" we don't have ducts. we have liquid R22 line. what's a duct temp? duct temp always stay in between 4 and 6 degree C. Is this the temp of small duct after the expansion valve which has further parallel branches in the evaporator ?

3: Does anyone has worked with the sabroe 128HM mkIII , i have problem understanding the functions of some pipe connections to the compressor.