Hello, I have a RTHA chiller that seems to be excessively loud compared to my other RTHA chillers in the same plant. The chiller loads and unloads from one extreme to the other within 2 minutes. When loading up I get an A74 on the display, my pressures are 52 psi/160 psi, my chw temp is 52in/45out, amperage is at 243a, 234a, 231a. when it unloads I get A77, my pressures go up to 84 psi/ 145 psi, my temp is 57in/49 out, amperage is 119, 113, 109. discharge superheat is at 43 deg, my temp drop across the ref filter is only 2-3 deg. I am guessing that i am low on refrigerant, but not 100% sure. I have gotten different responses from other technician coworkers, but I wanted to get a little more feed back from the Forum before making my final diagnosis.