The Reniso K-Series are highly refined, naphthenic mineral refrigeration oils formulated for use with ammonia (NH₃) refrigerant and also compatible with HCFCs, hydrocarbons, and non-miscible or partially miscible refrigerants.
They comply with DIN 51503 standards for refrigeration oils, particularly KAA (non-miscible with ammonia), KC (miscible with HCFC), and KE (for hydrocarbons) types.
Some of the commonly available grades of Reniso K include:
KM 32 — low viscosity for certain ammonia refrigeration circuits.
KS 46 — mid-viscosity for general ammonia or mixed refrigerant service.
KC 68 — heavier load or higher temperature duty.
KES 100 — high viscosity (100), recommended especially for systems with high evaporation and condensation temperatures, or large plants, or where the refrigerant load or temperature swing is large.
Reniso K oils are used in:
Refrigeration compressors using ammonia (R-717).
Systems employing HCFC refrigerants like R-22.
Hydrocarbon refrigerants (propane, propylene, isobutane etc.).
Open, semi-hermetic, and hermetic compressor designs.
Systems operating at low ambient / evaporation temperatures (requiring good cold flow).
Good ageing / thermal stability even when ammonia is present. Ammonia can be aggressive, so oils that resist decomposition are important.
Low wax formation at low temps (due to dewaxing).
Low water content (packaged dry) to avoid issues in refrigeration circuits.
Good miscibility when needed (for some types) or good compatibility with refrigerants.
Because mineral oils aren’t miscible with ammonia (in many cases), oil return in flood-evaporation or large ammonia systems must be ensured carefully (correct oil viscosity, correct piping, good oil separators etc.).
Some Reniso K grades (like KM, KS, KC) are non-miscible or partially miscible depending on the refrigerant; must verify compatibility with your specific refrigerant(s).
Cold start / flow: even with dewaxed oil, viscosity rises as temperature drops, so ensure selection matches lowest expected operating temperature.
Water / moisture contamination can degrade performance. Dry packaging and handling critical.
Some newer refrigerants (especially non-azeotropic blends, HFCs, or HFOs) may require synthetic oils or specially formulated lubricants rather than mineral ones, so check OEM compatibility.
