Drew
02-04-2011, 12:27 AM
Hey all,
I have two bitzer screw package units running a -24 C freezer.
The systems are independant of each other mechanically. The one unit runs well , while the other im having issues with oil return from the accumulator.
The oil that gets trapped in the accumulator drains to the bottom of the SA and then, via an oil return drain at the bottom of the SA, which is then connected to the sump of the screw, is drawn back to the compressor. In the oil return line is a sight glass and oil filter. From what i can understand the slight pressure difference between the sump and SA drives the oil back to the sump.
I have changed the oil filter , but still, after a period of weeks the entire oil charge ( from the oil sep) collects in the accumulator and the sytem shuts down on low oil level. I have seen the oil return down the line watching the sight glass so the oil is returning , so the pipe isnt restricted , but still over time the oil return seems to stop , while the other system has never had this fault. Im thinking that somehow the pressure difference that drives the oil return diminishes, but cant see how.
Between the SA and the compressor in the main suction is a filter cartridge , which has had the cores removed after a few months after the install. Could this assist in creating a slightly bigger pressure difference that would drive the oil better? Should i refit them?
I have two bitzer screw package units running a -24 C freezer.
The systems are independant of each other mechanically. The one unit runs well , while the other im having issues with oil return from the accumulator.
The oil that gets trapped in the accumulator drains to the bottom of the SA and then, via an oil return drain at the bottom of the SA, which is then connected to the sump of the screw, is drawn back to the compressor. In the oil return line is a sight glass and oil filter. From what i can understand the slight pressure difference between the sump and SA drives the oil back to the sump.
I have changed the oil filter , but still, after a period of weeks the entire oil charge ( from the oil sep) collects in the accumulator and the sytem shuts down on low oil level. I have seen the oil return down the line watching the sight glass so the oil is returning , so the pipe isnt restricted , but still over time the oil return seems to stop , while the other system has never had this fault. Im thinking that somehow the pressure difference that drives the oil return diminishes, but cant see how.
Between the SA and the compressor in the main suction is a filter cartridge , which has had the cores removed after a few months after the install. Could this assist in creating a slightly bigger pressure difference that would drive the oil better? Should i refit them?