Refrigerant for VRF systems
Why VRF charges are large
A VRF system is one outdoor unit feeding many indoor units through a branching refrigerant circuit. The pipework is the system. Charge is calculated from the base charge of the outdoor unit plus an additional amount per metre of liquid line, which is why two installations of the same nominal tonnage can hold very different quantities of gas.
The practical consequence for a building operator is that a VRF recharge is not a can of gas. It is a quantity that needs ordering, and on a system that has lost most of its charge it is worth knowing the commissioning figure before anyone starts weighing gas in.
R-410A, and why you cannot vapour-charge it
R-410A is a near-azeotropic blend of R-32 and R-125 in equal parts by weight. Near-azeotropic means it behaves almost like a single fluid, but not quite, and if you charge it as a vapour the two components leave the cylinder at different rates. What goes into the system is then not R-410A.
Charge liquid, cylinder inverted or using the liquid valve, metering into the low side so the compressor is not slugged. This is standard practice, and it is the single most common way a VRF charge goes wrong.
R-410A also runs at substantially higher pressure than R-22, roughly 50 to 60% higher, so gauges, hoses and recovery equipment rated for R-22 are not appropriate. See the operating pressures guide.
R-32 on newer VRF
R-32 is a single component, so it can be charged as vapour or liquid without composition shift, and its GWP is roughly a third of R-410A's. It is A2L, mildly flammable, which brings charge limits per room volume under IEC 60335-2-40 and changes the tooling and ventilation expectations on site.
For a building operator the useful summary is that R-32 VRF is not a drop-in for R-410A VRF. It is a different machine, and the two gases are never interchangeable in the same circuit.
What we supply for VRF work
R-410A and R-32 in the cylinder sizes listed on the R-410A and R-32 product pages, from Stallion and Refron (GFL), in original factory-sealed cylinders. For a planned recharge on a large system, tell us the quantity at the enquiry rather than the day before, because a multi-cylinder requirement in one size is worth confirming against stock.
Legacy VRF and older ductable plant still running R-22 is serviced under the existing-equipment route, and we supply R-22 for that under our ODS registration.
Quick answers
What refrigerant do VRF systems use?
Most VRF systems in India run on R-410A. Newer platforms use R-32, which has a lower GWP and is an A2L mildly flammable refrigerant with charge limits per room volume.
Can I top up a VRF system with a can of gas?
No. VRF charges are calculated from pipe length and are measured in tens of kilograms. A low system usually means a leak that needs finding first, then a weighed charge.
Why must R-410A be charged as a liquid?
R-410A is a blend of R-32 and R-125. Charged as vapour, the components leave the cylinder at different rates and the mixture entering the system is no longer R-410A.
Can R-32 replace R-410A in an existing VRF system?
No. They run at different pressures and R-32 is A2L, so the equipment, charge limits and tooling differ. The two are never interchangeable in the same circuit.
- ASHRAE Standard 34 · refrigerant designation and safety classification · ashrae.org.
- IEC 60335-2-40 · charge limits for A2L refrigerants in comfort cooling equipment.
- IPCC Fourth Assessment Report · GWP values used across this site · ipcc.ch.
This guide is general information compiled from the cited sources — not legal, safety or engineering advice. Read our full disclaimer.
Related: R-410A supply · R-32 supply · Operating pressures · A2L handling