Topping up an R-32 inverter air conditioner
Why the charge matters more on an inverter
A fixed-speed system runs at one capacity and cycles off when it has done enough. An inverter modulates compressor speed to hold a setpoint, and the control logic assumes the circuit has its design charge.
Undercharged, the unit runs at higher speed for longer to reach the same room temperature, which shows up as poor cooling and high running cost rather than an obvious fault. Overcharged, discharge pressure and temperature climb and the compressor is being asked to work against a condenser that is partly full of liquid. Neither shows a clean symptom, which is why guessing is expensive.
Find the leak
Refrigerant is not consumed. A system that was correct at commissioning and is low now has a leak, and the usual candidates are flare joints at the indoor unit, the service valves, and mechanical damage to the interconnecting pipe.
Adding gas without fixing it means the customer pays again in a few months, and on an A2L refrigerant a persistent leak in an enclosed space is a safety question rather than only a cost one.
Charging R-32 correctly
The right method on any split that has been opened is to recover, evacuate properly and weigh in the full nameplate charge plus the line-length allowance. That gives a known circuit rather than an approximation.
R-32 being a single component means a vapour top-up will not change what is in the cylinder or the system, which is a genuine advantage over R-410A. It still does not tell you how much is in there. Use a scale.
Never mix. R-32 into an R-410A system, or the reverse, produces a circuit whose contents nobody can identify, cannot be recovered correctly, and is running at pressures the equipment was not designed for.
A2L: what changes on site
R-32 is A2L, mildly flammable, with a low burning velocity. In practice: no ignition sources while the circuit is open, ventilate when working in a confined space, use tools rated for A2L, and respect the charge limit for the room volume under IEC 60335-2-40.
The A2L handling guide covers this properly. It is not dangerous work, but it is different work from R-22 or R-410A, and the difference is worth knowing before you meet it.
What we supply
R-32 from Stallion and Refron (GFL) in the cylinder sizes listed on the product page, subject to current stock. Technicians collecting gas from the shop can pick up vacuum pumps and other accessories on the same visit.
Quick answers
Can you top up R-32 without recovering the charge?
R-32 is a single component so vapour charging does not shift composition. But a unit that is low has leaked, and the leak should be found and fixed before gas is added.
Is R-32 flammable?
It is A2L, mildly flammable, with a low burning velocity and higher ignition energy than a fully flammable gas. Work with no ignition sources and adequate ventilation.
Can I put R-32 into an R-410A system?
No. They run at different pressures and the equipment is designed for one or the other. Mixing produces a circuit whose contents cannot be identified or recovered correctly.
How much gas does a split system take?
The nameplate gives the factory charge plus an allowance per metre of pipe beyond the standard run. Weigh the charge rather than estimating it.
- ASHRAE Standard 34 · A2L classification and burning velocity criteria · ashrae.org.
- IEC 60335-2-40 · charge limits for A2L refrigerants by room volume.
- 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-32 supply · A2L handling · Can you mix refrigerants? · Supply for technicians