HVAC professionals are required to maintain records of refrigerant sales, purchases, usage, and disposal. These records should include details such as the type and quantity of refrigerant, the date of transaction, and the identity of the supplier or customer. Additionally, records of system servicing, maintenance, and repairs, including refrigerant leak detection and repair, should also be kept. These records help track refrigerant movement through the supply chain and ensure compliance with environmental protection laws.