From ISO 32 to ISO 56: QISHANR 4GS in a Thai Supermarket Cold Store

By Qishanr Technical Team · Published 22 September 2026
Field report · QISHANR 4GS · Hanbell screw compressor, R22, about −25 °C cold storage, Thailand

TL;DR

• A supermarket cold storage operator in Thailand replaced a degraded ISO 32 oil with QISHANR 4GS, an ISO VG 56 naphthenic mineral oil, in a Hanbell screw compressor running R22 at about −25 °C.
• Our sales engineer asked for the compressor model and refrigerant first, then recommended 4GS instead of the 3GS grade the customer was about to reorder.
• Two months on: noticeably quieter running, oil pressure steady through load changes, and energy consumption about 8 % lower than before.

Case at a Glance: QISHANR 4GS in a Thai Cold Store

QISHANR 4GS is an ISO VG 56 naphthenic mineral refrigeration oil, the heavy-grade member of the GS series, blended from highly refined naphthenic base oils. It is specified for larger screw and reciprocating compressors where a heavier oil film is needed at higher bearing loads.

What Did the Cold Store Report After Switching to QISHANR 4GS?

The operator sent us a full review covering the technical result and the ordering process. Here it is in their words:

We switched the Hanbell screw compressor in our supermarket cold storage (running R22 at about −25 °C) to QISHANR 4GS, after the previous ISO 32 oil degraded and caused deposit buildup, noisy operation and fluctuating oil pressure. The sales engineer first asked about our compressor model and refrigerant, then recommended 4GS instead of the 3GS we almost ordered. The quotation was competitive and the payment terms were flexible. After placing the order, they updated us on production progress regularly. Delivery was on time; the drums were well sealed and the documents (MSDS, CO, CE certificate, invoice) were complete. After two months of operation, the compressor runs noticeably quieter, the oil pressure holds steady during load changes, and our energy consumption has dropped about 8 % compared with before. One small suggestion: it would help if the batch number were printed on the drum label, since we keep detailed maintenance logs. We are planning to order a full container next time.

Why Does a Cold Store at −25 °C Need an ISO VG 56 Oil Rather Than an ISO 32?

The grade question is a bearing-load question. A screw compressor carries its rotor shafts on hydrodynamic bearings, where the oil film alone separates the journals from the shells.

At a −25 °C evaporating temperature the machine runs a wide pressure ratio, so the bearings and the discharge side carry more load than a high-temperature cooling duty imposes.

That is where the two grades separate. Our selection guidance places 3GS (ISO VG 32, 29 cSt at 40 °C) on standard-duty work and 4GS (ISO VG 56, 56 cSt) on heavy-duty compressors that need more film strength at elevated temperatures.

An ISO viscosity grade describes an oil's kinematic viscosity at 40 °C, and kinematic viscosity in this class is measured under ASTM D445 at 40 °C and 100 °C. QISHANR 4GS measures 56 cSt and 6.1 mm²/s at those two points.

The thermal figure matters as much as the viscosity. A flash point of 185 °C gives the oil headroom against hot discharge gas, which is where a mineral oil on low-temperature duty begins to break down.

Refrigerant compatibility decides the oil family rather than the grade. 4GS is formulated for CFC, HCFC, ammonia, R600a and R290 systems, which covers the R22 plant this cold store runs.

R22 sits under the HCFC phase-out programme, and the U.S. EPA publishes the production and import controls behind it on its ozone-depleting substances pages. Existing plant keeps running through that transition, and it still needs an oil that matches the refrigerant in the circuit.

What Do Deposit Build-up and a Fluctuating Oil Gauge Tell You on a Cold Store Compressor?

Two symptoms pointed at the oil rather than at the control system: deposit build-up, and a gauge that moved whenever the load changed.

Deposit build-up means varnish and sludge: the film of degraded oil and oxidation products that collects on bearing surfaces and inside oil ports instead of circulating.

Once that film forms, oil flow through the galleries is restricted, and a bearing that is short of oil announces itself as noise. The customer had both.

Wax separation is the low-temperature half of the same problem. A naphthenic oil that is not wax-free can flocculate inside the refrigerant mixture, and that floc travels to capillary lines and expansion devices.

QISHANR 4GS is blended wax-free, with a pour point of −33 °C measured under ASTM D97.

A pour point is the temperature below which an oil stops flowing under gravity in a standardised test, and it sets how quickly oil returns to the compressor after a cold start.

Oil pressure that swings with every load and unload step is the third signal. It tracks an oil pump working against a restricted circuit, and it settles once the circuit is clear and the film is carrying load again.

The reading after two months is the one the operator described: noticeably quieter running, and a pressure gauge that holds steady while the system loads and unloads.

Why Was 4GS Recommended Over 3GS, and What Does Ordering Look Like From Thailand?

The order started with two questions, and both of them were technical: which compressor model, and which refrigerant.

That is the right order to ask them in. Grade and oil family are decided by those two answers rather than by what was in the plant before, and here the answer moved the order up a grade.

The customer had been about to reorder 3GS. Our engineer recommended 4GS instead, on the strength of the compressor type and the −25 °C duty, and the quotation and payment terms were settled around that specification.

Supply ran from there: regular production progress updates, on-time delivery, and drums that arrived well sealed — a point the operator raised, because a leaking drum means oil that has already taken on moisture.

The document set matched what the customer's own procedures required: MSDS, certificate of origin, CE certificate and invoice, alongside SGS certification of the product itself.

One request came back with the review. The operator keeps detailed maintenance logs and asked for the batch number to be printed on the drum label, so that a log entry can point at a specific batch.

It is a reasonable request from a maintenance team, and it is recorded here as the one improvement this customer asked for.

Their next step is already decided: a full container order.

QISHANR 4GS Reference Data

The table below lists the published 4GS values with the test method behind each one.

Grade selection followed a short, repeated sequence: read the compressor and the refrigerant first, then match the grade to the duty.

Fig. 1 — The selection sequence behind this order: the compressor model and refrigerant set the oil family, and the duty at about −25 °C moved the grade from the ISO VG 32 the plant had been running to ISO VG 56. Values for both grades are published figures.

Who Should Choose QISHANR 4GS, and When to Choose Differently

• Choose QISHANR 4GS when: the nameplate calls for ISO VG 56 in a mineral-oil circuit — larger screw and reciprocating compressors, supermarket and cold-store refrigeration, food processing plant, and heavy commercial duty where an ISO VG 32 film is thin for the load — see the 4GS specification page.
• Choose 3GS at ISO VG 32 when: standard-duty commercial and residential refrigeration, and the OEM specifies VG 32.
• Choose 5GS at ISO VG 100 when: a large screw compressor runs industrial low-temperature duty or carries shaft loads that need the heaviest film in the series.
• Compare the whole mineral refrigeration oil series when: the plant runs R22, R717, R600a or R290 and you need the grade matched to the compressor rather than to the refrigerant alone.
• Related case: a Bitzer CSH screw compressor on ISO VG 100 mineral oil where cold-start knocking and a swinging oil gauge were the reported symptoms.

FAQ: QISHANR 4GS in Hanbell Screw Compressors and R22 Cold Storage

Is QISHANR 4GS a suitable oil for a Hanbell screw compressor?

A: 4GS is cross-referenced to Hanbell HBR-A01 among its OEM equivalents, and it is an ISO VG 56 naphthenic mineral oil for larger screw and reciprocating machines. Confirm the grade on the compressor nameplate or in the unit manual before ordering.

Why was 4GS recommended instead of 3GS?

A: 3GS carries 29 cSt at 40 °C and 4GS carries 56 cSt, so the heavier grade holds a thicker film at higher bearing loads. Our guidance puts 3GS on standard duty and 4GS on heavy-duty compressors that need film strength at elevated temperatures.

Can 4GS be used in an R22 system?

A: Yes. 4GS is compatible with HCFC refrigerants including R22, and also with CFCs such as R12 and R502, ammonia R717, isobutane R600a and propane R290. Plants on R22 continue to run during the phase-down and still need an oil matched to that refrigerant.

What documents come with an export order?

A: MSDS, certificate of origin, CE certificate and a transport identification report for the sea leg, plus the commercial invoice. Product is SGS certified and drums are sealed before packing.

How do we confirm the correct grade before ordering?

A: Send the compressor make and model, the refrigerant, the evaporating temperature and the sump volume. Our engineering team checks the duty against the series and comes back with a grade recommendation — the step that changed this order from 3GS to 4GS.

Changing the oil in a cold store screw compressor? Send the compressor model, refrigerant and evaporating temperature — we confirm the grade, documents and lead time before you order.
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