Harp® 404A is a zero ozone depletion (ODP) hydrofluorocarbon
(HFC) refrigerant blend. Harp® 404A is a ternary blend of R125,
R143a and R134a (44%/52%/4%). It has been formulated to
closely match the properties of CFC R502. It is widely used in
new equipment that would have previously used R502 and
can with specific modifications be retrofitted into exiting R502
equipment.
Harp® 404A applications include medium and low temperature refrigeration
systems such as food display and storage cabinets, cold storage rooms, ice
machines, refrigerated transportation and process refrigeration. Since Harp®
404A has similar properties to R502, it is possible (with modifications) to use it in
existing R502 systems.