R449A
Also known as: R-449A
Short definitionThe A1 blend that replaces R404A in cold rooms. Its GWP is 1,397 and its temperature glides by about 4.5 K as it evaporates.
When an old R404A system is converted, the compressor and the oil can stay, because R449A is compatible with POE oil and its pressures and capacity are very close to those of R404A. It contains R134a, R1234yf, R125 and R32. It does not burn and its toxicity is low. Its greenhouse effect is about a third of R404A’s, so it stays under the F-gas limit; it is often specified for new freezer rooms too.
The thing the commissioning technician has to know about is glide. This blend has no single boiling temperature; it has a range 4–5 K wide. Superheat is read from the dew column of the table, subcooling from the bubble column. It is charged from the cylinder as liquid. The gas leaving the compressor is a few degrees hotter than with R404A, so compressor cooling is considered from the start in freezer rooms.