R404A is a nonflammable, low toxicity refrigerant that carries an ASHRAE A1 safety classification and offers similar properties to the refrigerant it replaces. It has zero R404A offers the best overall properties when compared to R-502. Its capacity and efficiency values are equivalent to R-502. It operates at comparable physical and thermodynamic properties which makes transitioning to new systems or retrofitting older systems easier. The compressor discharge temperatures of 404A can fall 9 °C (14 °F) lower than R-502, which may lead to longer compressor life and better lubricant stability.
Original equipment manufacturers (OEMs) recommend using polyolester (POE) oil in a unit’s compressor when replacing R-502 with R404A. After the oil change, R404A will offer the same operating range as R-502.
