the lock out feature 44 and permits operation of the fluid processing unit in some embodiments of the invention existing recovery units can be modified to have new software programmed onto the controller 42 and the filtering receiver 28 can be modified in accordance of the invention in other embodiments of the invention current designs of recovery recycling recharging units can be modified so that future built units will have the controller programmed to control software that will operate the lock out feature 44 as described herein in addition the recovery unit will be equipped with a filter receiver 28 with filter 10 in accordance with the invention an example of a recovery recycle recharging unit that can be modified to have a controller a sensor and lock out feature along with a filter receiver and filter dryer in accordance with the invention is the recovery recycle recharging unit that is currently sold by the spx corporation under the tradename robinair and identified as the model 34788 after reviewing the disclosure contained herein one skilled in the art could modify such a refrigerant recovery unit such as the robinair model 34788 or other similar refrigerant recovery units to be in accordance of the invention another refrigerant recovery.