Cryo Refrigeration Help

[Cryo99]

To me the liquid reciever has to maintain a liquid level at all times , otherwise economizer will suffer as well .

Are you talking a level in the HP receiver? I am sure you are correct, but for the year I have been watching the unit it is rare to have a level here. The lines to and from this vessel are on top, so should this vessel be flooded? If not how does the liquid leave.

As Gary has mentioned non condensibles are of concern as well as condensor efficiency .

While I am not positive, from the data in the previous post, I think we are on the curve, so I don't expect non-condensables. If they are a problem it is only in the condenser as we took a sample off a high part of the unit and things looked normal (99% propylene).

It could also be the rock filter drier banking up liquid in condensor . Is there a bypass or has anyone changed them + cleaned filter if it has one ?
Normally filters are on liquid line from liquid reciever to economizer .

The rock fitlers were changed last week and we didn't see any improvement. There doesn't seem to be any unexplained DP across the rock filters.

You may also have to investigate higher than normal levels in economizer and low temp accumulator as this is an area also that will be storing excess refrigerant that should be in liquid reciever .
Can you shut liquid makeup from reciever to economizer with stop valve and see what happens to levels and pressures .

What type of level control system is installed on economizer + low temp accumulator ?

I lowered the levels in these vessels and didn't really see any change other than the compressor unloading. I also didn't gain level in the HP receiver, so I am not sure where the refrigerant went, but...