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View Full Version : Superheat on a freezer running on R-404



Lancelot52
27-12-2013, 03:43 PM
Hey you all, glad to be part of your community !!! My name is Pierre Paquin, I live near Montreal Canada and I' ve been working in the refrigeration field for about 20 years.

We have a walk in freezer that is about 23 feet long by 10 feet wide by 9 feet high, it used to run on an old 1958 Dunham bush belt driven compressor with a water condenser, with an 7.5 hp electric motor, the bosses here hired a company to change everything, compressor , evaporator and so forth, the company installed a Bitzer compressor type: 2C0572SL-5SU Serial : 1676801309, the condensing unit is inside and one floor lower than the evaporator with about 100 feet of tubing. It runs on R-404 with a thermostatic expansion valve. We find that there's an important frost back on the compressor, half of the compressor is icy, what should be the superheat on that freezer? .We are arguing with the company and we don't want to be served bullcrap you know !!!

Thanks for reading and have great holidays

Magoo
28-12-2013, 02:12 AM
hard icing back to compressor body indicates the evaporator super heat is wrong. Too low. Suction super heat above saturated suction temp at actual compressor should average 10' C.
The enthalpy of saturated suction vapour will not form ice at compressor suction valve if evaporator super heat is set up correctly and suction line losses are designed and installed correctly, assuming of course that equipment selection as installed is / has a balanced design. Who knows.
Check the search box at top right hand side of forum page and search for TX super heat set up, there is a truck load of information about super heats already on the forum.
cheers magoo

RusBuka
28-12-2013, 01:38 PM
1. What temperature in freezer you need? evaporation and condensation temperature and pressure?
2. Discharge superheat, and temperatures of heads?