What type of recovery equipment is generally prohibited for use when the appliance contains significant amounts of refrigerant?

System-dependent recovery equipment is typically prohibited for use when the appliance contains significant amounts of refrigerant because it relies on the refrigeration system itself to assist in the recovery of refrigerant. This type of equipment does not have its own reservoir or means to fully recover refrigerant without needing the compressor or other components of the system to operate. In cases where large amounts of refrigerant are present, it is essential to ensure that the recovery equipment can independently extract the refrigerant without over-reliance on the appliance's operational components. Using system-dependent equipment could result in inefficient recovery and potential environmental harm if any refrigerant escapes during the process.

By contrast, recovery equipment designed for low-pressure systems, portable recovery units, and equipment that meets or exceeds EPA standards are more suited for recovery tasks. Low-pressure systems often have their designated recovery protocols, while portable units are designed to handle varying capacities effectively. Equipment adhering to EPA standards ensures that the recovery process is safe and compliant with regulations aimed at protecting the environment.