15 in an ongoing manner thus one or more backup systems may be employed to prevent overfilling by which the master control 30 locks out the recovery evacuation pump 40 in the event of a total weight exceeding the maximum allowed a reset switch in a secure area of the machine or a special code entered by keyboard or other data entry system may be used to zero the total with each new replacement storage reservoir 15 the tracking of storage reservoir 15 content 16 by the master control allows a second level of accounting between the recycling company and the distributor the recovery system generally is situated at the facilities of a distributor who generally accounts directly with his customers for recovered refrigerant the recovery system according to the present invention therefore alleviates the burden of small recovery cylinder management on the distributor while maintaining the service the value determination of the recovered refrigerant will thus depend on the identification quality of the commodity the current market value of the commodity the amount of the commodity and possibly the contractor 39 s relationship with the wholesale supplier the master control 30 of the present system is capable of performing a complete and detailed valuation of the refrigerant 2 content of the transfer vessel 1 and keeping an account of that value however in some cases this functionality is not needed in fact the weight and acceptance rejection status of the transfer vessel 1 refrigerant 2 contents may be sufficient information to be used by the wholesale supplier to assign the value and maintain the accounting an alternate arrangement allows the wholesale supplier.