Walk in freezer!!

[COBRAKAI]

Need advice my super techs!!!

Recently went to a walk in freezer. The problem was it will not drop bellow -13. My first thought it was the expansion valve, was going to change the orifice. The pressures where 2 Bar back pressure and 16 bar head pressure. The system is operating on R404a and it is a robert scutt condenser pack. Lunique compressor! However while I was checking the system the compressor was wheezing loudly and starting to judder. I decided that the compressor was starting to fail. Changed the compressor but ended with same issue! pressures are slightly better at 1.1 Bar back pressure. But cold room will not drop below -14 this time with evap probe reading -21. Should I have went with my first assessment or am I over looking something???

[install monkey]

whats ur suction superheat and cond subcooling,air on/off evap and condenser

[chemi-cool]

Typical parts changing engineer.
There are so many things to check before you start changing parts. Check all the system components, temperatures, pressure, refrigerant amount and quality, compressor, etc. etc.
after you find the faulty part, replace it.