MRCOOL 18K BTU Advantage 5th Generation Ductless Mini-Split Heat Pump Condenser

Hi Mark, the MRCOOL 18K BTU Advantage 5th Generation Ductless Mini-Split Heat Pump Condenser uses R-454B refrigerant and is a 5th generation unit. Older MRCOOL units, such as a 5-year-old system, typically use R-410A refrigerant and are generally 4th generation or older. Due to the difference in refrigerant types and system designs, 5th generation units (R-454B) are not compatible with 4th generation or older units (R-410A). To confirm the exact compatibility for your specific unit, please provide the complete model number of your existing 5-year-old Mr Cool 18k BTU, 1.5 ton unit. This will allow us to verify its generation and refrigerant type.