I have a trane chiller model # CVHE500 that has a problem with surging after initial startup. When I switch over to this chiller, as soon as the vanes start opening the chiller starts surging very loudly. I look at the head pressure and it is at -0.1 psig. I assumed if there was air in the condenser it would be reflected in high head pressure while the machine is surging which is not the case. Also, when this machine is started, the chilled water is already down to 50F due to a redundant chiller that was already running, so not a big load on the machine. Also, the condenser water does not have a chance to pick up any heat before the machine starts surging severly, it is still around the pre-start temperature of 79F. I did notice multiple excessive purge warnings in the history alarms of the chiller. Could it have so much air in the system that the machine cannot load up to register the high condenser pressure?