An unloader valve for a scroll compressor to selectively communicate suction and discharge is positioned outwardly of the compressor housing. In this way, the unloader valve is ideally positioned to address several system failures. As an example, loss or charge, reverse running, fan failure, etc. are all addressed in an efficient and quick manner. The unloader valve may be the normal unloader valve controlled by a system control which also selectively controls capacity. The unloader valve control is modified such that it is also operable to open the unloader valve when a system failure is detected.