critical charge

[aham]

what is meant by a critically charged system. i am working with a refrigeration contractor and he mentioned that he is designing a single stage R507a critical charged system.

I understand the single stage aspect of refrig. systems, i am just not clear on the critical charge portion of the statement.

[Brian_UK]

With critical charge it means that there will be a specific weight of refrigerant to be charged.

The designer will decide on the amount; it often applies to capillary systems.

[taz24]

what is meant by a critically charged system. i am working with a refrigeration contractor and he mentioned that he is designing a single stage R507a critical charged system.

I understand the single stage aspect of refrig. systems, i am just not clear on the critical charge portion of the statement.

With critical charge it means that there will be a specific weight of refrigerant to be charged.

The designer will decide on the amount; it often applies to capillary systems.

And to add onto what Brian says.....

The charge weight is critical for the correct opperation of the system.
If it is under or over charged by even a small amount it can have serious
effects on the working system, in some cases if over charged, the system
could be damaged and very expensive to repair. But undercharged can have
equal consiquences but for completely different reasons.

Simply put, If it is over charged then you run the risk of liquid returning to the compressor.
If it is under charged you run the risk of poor cooling effects and an overheating compressor.

Both serious but for different reasons..

taz

.

[Brian_UK]

I suppose you could also refer to the maximum charge that the compressor can handle before being flooded being critical.