06-24-2007, 09:33 PM
I work for a air compressor company, many air compressors have refrigerant dryer's in them. These dryer's main difference from a many residental systems in they contain a insulated heat exchanger for an evaporator. I was sent last week to replace a locked up compressor. I changed out the liquid line filter, and the Hot Gas Bypass Valve HGBV along with the compressor. I did an exact charge of 3.9 Kg of R404 after vacuuming the system for 3 hours, down to 750 Microns. When I went to start the dryer, it fail to come on. I tried lowering the pressure switch from 70 psi and it turned on and off; I lowered it some more and again it did the same. I turned the HGBV in, my gauge pressures lowered around70 to 60 psi, it started running but not cooling. I took amp load readings and found the 3 phase comressor to be pulling 8amps on a 16 FLA compressor. The compressor eventually kicked off on thermal overload. Any help?