Liebert model ct543a-as serial 311590-006 This is a three module chiller used in process at hospital. I happened across this on a PM, so this condition could have been occurring for a few months. #2 module was running but obviously not pumping so I put my gauges on and it was in a vacuum. The diagnosis was fairly simple a broken cap tube on TXV sensor bulb. The compressors are semi hermetic about 15 ton Carlyles. I replaced powerhead and contactor and compressor came on line ran beautifully, good amps and pressures. A penn low pressure switch is used on this machine but apparently only on a pump down situation because after the call ceased the control functioned properly. Megged compressor no damage, amazing. No jumpers on machine. Time delay parrallel to low pressure. About a year ago this happen on another Liebert chiller I was servicing. Is the only low pressure protection on this model the freeze stat, which would not be affected by the sudden loss of pressure? Don't have schematic in front of me now.