I have to repair a 640 liter well freezer, with 404 refri and needing at least -18. to preserve ice cream The first thing I noticed was that I had little low pressure, 4 negative psi. and froze the return a little. the temperature in the upper part of the interior was adequate, but in the bottom it was lower, -9, and in the lower parts it did not frost. I add coolant, it starts to frost below and the entire return to the compressor is filled with ice. I leave the pressure at 15 psi, the next day down marks -18, and so for two days, the third marks -15 below. The client tells me that this temperature is not enough to keep ice cream. Will it be a half-clogged filter ?, and I would also like to know what to do if, when removing the filter, it is full of oil, thanks.

Hello Possibly what you say If you find oil in the filter, you have to start from scratch, good cleaning of the surgeon, empty ......... Regards

If you find oil in the filter, maybe the compressor already spits a lot of oil and you have to cheat it, regards

You will surely find oil in the filter. That is because he worked with low vacuum pressure. The R-404a when there is a leak is not recommended to increase, you have to discard the remaining gas and charge it again. This is because it is not a pure gas, it is mixture. As colleagues tell you, change the filter, clean the system with nitrogen and charge gas again. Of course you must find the leak first.