cascade system

[sagittarius]

Hi,all
Who can tell me how to operate a cascade system?
High stage is R22.Low stage is R23.
charging refrigerants?
special cases to be attention during operation?
.....
Of course it is best there is a correlative manual . I'm a greener to this system.
:):):)

[TXiceman]

First thing to do is to get the high temp stage down to temperature. Charge in a conventional manner for the R-22.

You will need to vacuum dehydrate both systems to a fairly dry state and break the vacuum with the appropriate refrigerant.

Hope fully the R23 system is design properly with an expansion tank or a fade-out drum. It should be a critical charge system.

With the high temp system operating, charge vapor into the R23 side of the cascade condenser until you can get a liquid seal on the low temp system. Now start the low temp compressor and trim the charge as you are down to temperature.

Ken

[sagittarius]

Thanks,TXiceman.
To avoid the air in R23 system,I wanna purge R23 through the low stage,about 2~3bar,is Ok?

[norseman]

If this is a already made system, I would have looked for the spesifications on the unit. The high stage capacity and temperature should be correct at the start. Do not look for a "normal" pressure reading on it because a high stage without load can go into wild low pressures. Earlier days I was used to R12 on the high and it went to -45c so people without knowledge always filled the high up and made a new problem to another. The low stage in most cases use a static filling pressure by ambient which give you the best charge. Some other make a static after a run and in such systems, I normally charge +10% which drop down to correct on the new test after after test warming up. If you charge a low stage just by looking for an end temperature, you have to be careful so you not overcharge the system. You can get dangerous pressure when it warm up again.

Have a nice weekend you all