Suniso SL-220S

Suniso SL-220S 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 220 heavy grade serves screw compressors and high-load bearings requiring maximum film strength — with remarkably deep miscibility on R-134a and R-410A.

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 in commercial refrigeration; SL-220S (VG 220) where the OEM specifies a heavy grade — large screw compressors, high-load journal and thrust bearings, and R-134a chiller duty. Other ISO grades in the SL series can be brought in to order.

Do not "upgrade" a compressor to a heavier grade. VG 220 is specified because the bearing loads and oil-injection design call for it; putting it into a machine designed for VG 32 or VG 68 starves the circuit and hurts oil return rather than helping it. Equally, never run a VG 220 machine on a lighter grade because that is what was on the van. If the nameplate is unreadable, send us the compressor model and we will confirm the grade.

POE and mineral oil are not interchangeable. Suniso 3GS, 4GS and 5GS are the mineral-oil grades for R-22 and R-12 plant; SL-series POE is not a drop-in substitute in either direction, and a change between the two needs a proper flush and oil-change procedure.

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 charging, use an opened pack promptly, never decant into an open container, and fit a fresh filter drier whenever oil is changed.

Order SL-220S when a screw compressor, large industrial chiller or heavily loaded reciprocating machine specifies an ISO VG 220 polyolester — scheduled oil changes, oil-separator top-ups, and post-overhaul refills on plant where the OEM has called out the heavy grade.