Post by turbokinetic on Sept 12, 2019 12:42:17 GMT
Fridge Tech needs to know how much R-12 is needed to to fill my FEA with.
Waiting to hear............................................................................
Thanks, Bill
It has to be charged by "frost line." There may be someone who has a better idea of the exact amount; but until then, this will assist.
The FEA has a "flooded evaporator" design. The evaporator fills with refrigerant starting with the tubes around the bottom. This part fills with refrigerant until the level reaches the "header" which is a storage tank for the surplus refrigerant.
If the charge is being put in from cans; you could start with one can. See if a frost line develops.
These pictures will be helpful most likely:
"Very heavy load" would be initial pull-down in a hot environment, running with no cabinet (as above), or with the door open, the frost line can be on the return line; however it should not frost above the top deck and on the outside of the unit.
"Heavy Load" would be with door opened quite a lot, high ambient temperatures with normal use of the fridge, etc.
"Light Load" would be a good cabinet (door gasket in new condition, perfect insulation, etc.) not opened often.
As long as the frost line stabilizes somewhere on the header, after the machine has been running and cycling for several days, it's just fine.
The above pictures are of a FEA top which belongs to another member. It was in unknown condition. Someone else installed the aluminum charging connections to it, which I don't approve of. We wanted to see how it functioned, so I chose to use them for a test. Ordinarily we would use the hermetic service connectors; or solder in some legitimate service ports.
That aside, the charging process I used was based on frost line. Unfortunately, I can't tell you how much refrigerant was used. The refrigerant came from a recovery tank, which I didn't weigh during the charging process. Also, the refrigerant was R152A. It has different density from R12, therefore even if we had weighed the tank, the information would not help you since you're using a different refrigerant.
The safest way to begin is to start with the system in a complete vacuum and your hoses connected to the low-pressure side. Then equalize the system with the refrigerant can, allowing vapor only (not liquid) to enter the system. After the system has pressure of vapor in it, start the compressor. Allow it to draw in vapor from the can. Allow the can to frost and allow the compressor to slowly draw vapor from the can. Observe the evaporator for any developing frost line. Once the first can of refrigerant is in the system, switch to the second can. Begin charging vapor again, progressing slowly so as not to overload the compressor. Once the can is frosted, open the valve fully and allow the compressor to continue drawing vapor. Watch for the frost line on the evaporator. With the cabinet door open and the unit therefore under a heavy load; charge it until the frost line is at the top of the header.
Hope you find this helpful!
Sincerely,
David