How do I know my mini-split is low on refrigerant?
Weak cooling or heating, ice on the indoor coil or copper lines, longer run times, a hissing or bubbling sound, and certain error codes are the usual signs. Mitsubishi Electric's manual notes that when the unit does not cool or heat, there is a possibility of refrigerant leakage, and some brands flag it directly: LG says CH38 / F4 means the unit is low on refrigerant, and MRCOOL lists EC as a refrigerant leak on its first three generations.
Can't someone just recharge it?
Refrigerant doesn't get "used up" — if the charge is low, it escaped through a leak, and it will keep escaping. A proper repair is: find the leak, fix it, pull a vacuum to remove air and moisture, then weigh in the correct charge from the nameplate. On mini-splits, leaks are often at the flare connections where the line set meets the indoor or outdoor unit, though coils and service valves leak too.
Who is allowed to work on refrigerant?
Federal rules are clear. EPA requires technicians who maintain, service or repair equipment that could release refrigerant to be certified under Section 608, and specifically says that adding or removing refrigerant from a mini-split, or connecting gauges, requires Section 608 certification. Ask whoever comes out to confirm it. If you'd like help finding someone who works on ductless systems, our mini-split repair line for Florida routes calls by ZIP code.
Does a leak mean I need a new system?
Not necessarily. A single flare-joint leak is usually a reasonable repair. A leaking coil, repeated leaks, or an older system that uses a refrigerant that's becoming harder to source are when replacement is worth discussing. Get the leak location and repair cost in writing so you can compare.
Related problems
Low refrigerant often shows up first as poor cooling or heating, an error code, or icing that later turns into water dripping from the head.