Never top up refrigerant yourself
DIY regas kits aren't a shortcut. The Australian Refrigeration Council says handling fluorocarbon refrigerant without a Refrigerant Handling Licence is an offence, and its FAQ describes it as one of strict liability. If you think the unit is leaking, Mitsubishi Electric's advice is to stop it, ventilate the room well and call for service straight away.
How do you know it's low on refrigerant?
You can't be sure until a technician measures it. The usual clue is a system that runs but no longer cools or heats like it used to. Mitsubishi Electric lists refrigerant leakage as one possible cause when a unit won't cool or heat, and warns that refrigerants may have no smell, so your nose won't tell you.
Plenty of simpler faults look the same: dirty filters, the wrong mode, or an outdoor unit boxed in by plants. Rule those out with our not cooling guide before you book.
How a licensed technician should handle it
Confirm it's the refrigerant
They measure the system's pressures and performance rather than guessing from the symptoms.
Find where it's escaping
The leak could be at a pipe joint, in a coil or along a damaged length of pipe. The fix depends on where it is.
Repair, then test
The leak is repaired and the system tested before any refrigerant goes back in. That order is the law, not a preference.
Recharge with the right refrigerant
The ARC says equipment must not be charged with a refrigerant that has a higher global warming potential than the one it was designed for. Mitsubishi Electric's manual for one of its splits says nothing but the specified refrigerant (R32) may enter the circuit.
Who's allowed to do it?
Only someone with a full RAC01 licence. The ARC says the restricted Splits licence (RSS03) lets a person install a single-head split, but not come back to do any service, repair or maintenance that involves the refrigerant.
That makes this a job for a refrigeration and air conditioning technician who does leak repairs regularly. Their licence number starts with L, the business's RTA number starts with AU, and the RTA number has to appear on the quote and the invoice.
Warning signs in a regas offer
- A regas sold as a yearly maintenance item.
- A top-up with no leak test, or an offer to gas it up and see how it goes.
- No licence number or RTA number on the quote or invoice.
- The same unit needing gas again a few months after the last top-up.
What's yours to check, and what isn't
You can
- Check the filters, the mode and the set temperature before you book.
- Make sure the outdoor unit has clear air around it.
- Note when the problem started, and whether you've seen ice on the pipes.
- Switch the unit off and air the room if you suspect a leak.
Leave to a licensed installer
- Measuring pressures and finding the leak.
- Repairing and testing the system.
- Recharging with the refrigerant on the unit's rating label.
- Recovering the refrigerant safely if the system is replaced instead.
What we'd do
Where we'd start
Rule out the filters, the settings and the outdoor unit first. If it still won't cool or heat properly, book a leak repair rather than a regas, with an RAC01 technician, and ask them to show you where the leak was and what they did about it. On an old system with a leaking coil, weigh up replacing it: Solar Victoria's 2021 buyers guide puts a system over 15 years old at more than three times the energy use of a modern reverse cycle model.
