What is the recovery level for very high pressure appliances before November 15, 1993?

The recovery level for very high pressure appliances before November 15, 1993, is indeed 0 psi. This means that when recovering refrigerant from appliances classified as very high pressure (those using refrigerants with a boiling point lower than -50°F or -45.6°C), technicians were permitted to stop recovery efforts once the pressure reached atmospheric pressure.

This guideline was established to ensure safe recovery practices, as very high-pressure refrigerants can pose distinct hazards. The regulation signifies that it is acceptable to leave the appliance at 0 psi, as long as the technician has taken the necessary steps to ensure environmental and safety standards were maintained during the recovery process.

The options related to higher recovery levels such as 4, 10, and 15 psi would imply a requirement to achieve specific pressures of refrigerant recovery, which is contrary to the regulations that were in place during that time period. The focus of the regulation was on the safety of ending recovery at atmospheric pressure for very high-pressure appliances.