What is required for existing refrigerant access ports located outdoors whenever refrigerant is added?

The requirement for refrigerant access ports located outdoors whenever refrigerant is added is the use of tamper-resistant caps. These caps are essential for ensuring the integrity and safety of the refrigerant system. They prevent unauthorized access to the refrigerant ports, reducing the risk of refrigerant leaks or contamination from external elements. The design of tamper-resistant caps typically makes it more difficult for individuals without the appropriate tools to remove them, thereby protecting the system from both environmental factors and potential tampering.

While other options like foam insulation, weatherproof covers, and locked valves may offer some level of protection or insulation, they do not specifically address the need to prevent unauthorized access to the refrigerant ports. Tamper-resistant caps specifically fulfill the requirement for safety and security for outdoor refrigerant access points.