Suniso SL-68S

Suniso SL-68S is a fully synthetic polyolester (POE) refrigeration oil from the Suniso SL series — formulated with select polyolester base stocks and additives for excellent miscibility with HFC refrigerants in compressors for refrigerators, freezers, air conditioners, chillers, and industrial refrigeration systems. The VG 68 grade is the mid-viscosity workhorse specified widely for reciprocating and screw compressors in commercial refrigeration.

The Suniso name has set the standard in refrigeration lubrication since 1933; the SL series carries that pedigree into the HFC era with the low-temperature miscibility data (published per refrigerant, below) that lets an engineer verify oil return at design conditions rather than hope for it.

Which grade you need is set by the compressor, not by the refrigerant. Read the nameplate or the OEM service manual and match the ISO viscosity grade. In our stocked SL range: SL-32S (VG 32) for scroll and small reciprocating compressors, mostly R-410A air conditioning and R-134a commercial plant; SL-68S (VG 68) for larger reciprocating and screw duty — typically R-404A/R-507 cold rooms, packs and blast freezers; SL-220S (VG 220) for screw compressors and heavily loaded bearings. Other ISO grades in the SL series can be brought in to order.

POE and mineral oil are not interchangeable. If the compressor plate calls for Suniso 3GS, 4GS or 5GS, that is the mineral-oil family used on R-22 and R-12 plant — an SL-series POE is not a drop-in for it, and an HFC compressor will not survive on mineral oil. Converting between the two needs a proper flush and oil-change procedure, not a top-up. Send us the refrigerant and the compressor model and we will confirm the grade before you buy.

Handle POE oil as a moisture-sensitive product. It absorbs water from the air far faster than mineral oil, and absorbed moisture becomes acid inside a running system. Keep containers sealed until the moment of charging, use an opened pack promptly, never decant into an open jug or leave a can standing on the bench overnight, and fit a fresh filter drier whenever oil is changed.

Order SL-68S when a semi-hermetic reciprocating or screw compressor on R-404A, R-507, R-407C or R-134a is due an oil change, when a cold store or process pack is being commissioned, or after a burnout where the charge and oil are both being replaced — VG 68 is the grade most commercial refrigeration compressors in Indian service actually call for.