Hi,

I just found a walk-in freezer retrofitted previously by a different company. It has an R404a condensing unit and an R22 evaporator. After not gaining the correct superheat (it was 34 at the condensing unit and 22 at the evaporator outlet), I took it apart and found an R22 expansion valve , with the screw on the top fully turned out.
The owner thought the reason for not cooling properly is because they are using it too often, but having a look at the evaporator coil, it wasn't even frozen only on the 1/3 section of the coil. I think a new expansion valve is needed, the question is, how do I choose it?
It has a CAJ2464Z compressor and a Danfoss TEX2 68z3209 q-71322 -40/+10 expansion valve.
Unfortunately that is the only information available of the system...
Any help would be greatly appreciated.

Thanks