The Coldest Month: Daphne FVC68D in Two R-404A Cold Store Circuits

By the QISHANR Technical & Supply Team · Published 13 October 2026
Case review · Daphne FVC68D (polyvinyl ether, 66.57 cSt at 40 °C) · Two low-temperature circuits on R-404A

TL;DR

• A cold store runs two low-temperature circuits, both on R-404A, and its plant room is coldest in January.
• The specification came back as Daphne FVC68D, ISO VG 68, at 66.57 cSt at 40 °C and a pour point of −37.5 °C.
• Its flash point is quoted open cup, which does not compare with closed cup figures.
• A full cold season passed without an oil problem.

Case at a Glance: Daphne FVC68D in a Cold Store Plant Room

Daphne FVC68D is a polyvinyl ether refrigeration oil published by Idemitsu Kosan, with a measured viscosity of 66.57 cSt at 40 °C.

What Did the Customer Report?

We asked the operator to write down how the season went and what the specification reply contained. This is the note he sent.

We look after two low-temperature circuits at a cold store, both on R-404A, and our plant room is at its coldest in January. That is the month the oil in a compressor has to prove itself, and the grade we had before did not enjoy it.

I sent QISHANR the two circuits and asked what they would put in them. They came back with Daphne FVC68D, the ISO VG 68 grade, and I liked that the reply had numbers in it rather than adjectives: 66.57 cSt at 40 °C, pour point -37.5 °C. They also told me the flash point on this grade is quoted open cup, which is not the same thing as the closed cup figures I had been lining up against it. I have been buying refrigeration oil for a long time and nobody had ever said that to me.

A full cold season later, both machines are still running on the grade. Winter came and went without an oil problem, top-ups were easy, and the cans are still fluid enough to work with when the store is at its coldest. The order reached us in about three weeks. Two other stores in our group run the same circuits, and I have passed the grade name on to both.

Why Does a Low-Temperature Circuit Put the Oil Under More Pressure?

A low-temperature circuit runs at a low evaporating temperature, and oil at that end of the system is thicker and slower to find its way back to the compressor. A pour point is the temperature at which an oil stops flowing under the test conditions, and it is the figure that shows how far a charge can be pushed before it stops moving. It is measured under ASTM D97.

Within ISO VG 68 the DAPHNE range holds two grades, and they are not interchangeable on a cold circuit. FVC68D is 66.57 cSt with a pour point of −37.5 °C. FV68S is 69.6 cSt with a pour point of −32.5 °C. Both carry the same ISO class, and five degrees of pour point is the whole difference between a grade that suits a cold store and one that does not.

The range reaches lower on that figure as well: FVC32D is 32.4 cSt and is quoted at −47.5 °C.

The customer's own test of the number was practical. The cans stayed fluid enough to work with when the store was at its coldest, which is what a pour point of −37.5 °C allows for.

Can the Flash Point on This Grade Be Compared With a Closed Cup Figure?

The 206 °C published for FVC68D comes from an open cup method, and a closed cup test on the same oil would give a different number.

An open cup flash point is measured with the sample open to the air, so vapour escapes as the sample heats. A closed cup flash point is measured with the sample sealed inside a covered vessel, so the vapour stays in. The two methods do not produce the same figure, and an open cup reading is usually the higher of the two. The open cup method is ASTM D92.

That is what the customer had been caught by. Closed cup figures line up against closed cup figures, and the comparison falls apart the moment one number on the page comes from the other method.

The mistake is invisible while it is being made, because both figures are in degrees Celsius and both look like a flash point. Put an open cup reading where a closed cup figure belongs and the grade lands in the wrong place against a competitor's sheet or against an OEM limit.

The wider point covers any figure that arrives without its method attached. Viscosity, water content and acid number are each quoted to a specific standard, and the number on its own does not tell you whether it can sit beside another number.

Daphne FVC68D Reference Data

The values below are the manufacturer's published figures for the grade, with the test method each one was measured to. Kinematic viscosity is measured under ASTM D445.

What Ships With an FVC68D Order?

Payment is by T/T or L/C, and price terms follow any Incoterms 2020 rule from EXW through to CIF, quoted against your destination port. Supply on this grade is 1,000 pieces a year.

The order ships as the original Idemitsu Daphne product or as Qishanr QSL-68H, our equivalent in the same ISO class, blended at our plant in Foshan. Pack size is confirmed at quotation, and the drums in the customer's photograph are the 200 litre pack.

The technical data sheet and the safety data sheet come with the quotation, and a certificate of analysis for the delivered batch travels with the shipment. Export documents are issued as standard: CE, certificate of origin, MSDS and the transport identification report. Private label and own-brand packing are quoted as an item, and trial quantities are supplied alongside wholesale orders.

Lead time is confirmed on the quotation. On this order it ran to about three weeks.

Who Should Run This Grade, and When Should We Be Asked First?

• Run it on low-temperature circuits where the refrigerant is an HFC such as R-404A, R-134a, R-407C or R-410A.
• Compare the sibling grade before ordering when the pour point matters more than the viscosity class, since FVC32D reaches −47.5 °C.
• Take a polyol ester instead when the compressor is charged with POE, because PVE and POE are separate oil families and are not interchangeable.
• Ask us first before a machine on CFC or HCFC refrigerant is converted, or before a mineral oil machine is switched over.
• Compare the wider range when a site holds more than one oil family, which the refrigeration oil collection sets out by family and measured viscosity.

FAQ: Daphne FVC68D, Test Methods and Low-Temperature Duty

Is 206 °C a high flash point for a refrigeration oil?

It is a normal figure for this class of oil, and it is quoted open cup. The comparison that matters is against another open cup figure rather than against a closed cup number from a different sheet.

Which refrigerants is FVC68D published for?

HFC refrigerants: R-134a, R-404A, R-407C and R-410A. The grade is a polyvinyl ether, and the oil family has to match the refrigerant in the circuit.

What is the difference between FVC68D and FV68S?

Both sit in ISO VG 68. FVC68D is 66.57 cSt with a pour point of −37.5 °C, and FV68S is 69.6 cSt with a pour point of −32.5 °C, so the two separate on low-temperature behaviour rather than on viscosity class.

What documents come with an FVC68D order?

The technical data sheet and the safety data sheet come with the quotation, and a certificate of analysis for the delivered batch travels with the shipment. Export documentation covering CE, certificate of origin, MSDS and the transport identification report is issued as standard.

Can FVC68D be used in a compressor charged with POE?

PVE and POE are separate oil families. Where a machine is charged with POE the oil family has to match it, and we will confirm the grade for that compressor from its model and the refrigerant in it.