This page exists because current mini splits use A2L refrigerants - R-32 and R-454B - which are mildly flammable, unlike the R-410A they replaced. Systems built for A2L carry a refrigerant sensor and a set of leak-detection codes, and those codes behave differently from ordinary faults: they are stop-use events rather than things to work through.
What the codes look like
Every one of these is technician-level. There is no homeowner fix, and that is by design.
Midea and ACiQ publish six, and notably these two brands share an identical 44-code table - ACiQ units are built on the Midea platform, so ACiQ owners can read Midea documentation for their system:
- EHC1 - leak alarm from the indoor refrigerant sensor.
- EHC2 - the sensor reading is out of range while leakage is also detected.
- EHC3 - the leak-detection sensor cannot be trusted.
- FHCC - the leak sensor is not working correctly.
- EL0C - the system believes refrigerant is missing or leaking.
- ECC1 - see below, because this one confuses people.
MRCOOL publishes the same family on its R-454B DIY-5 line as EH C1, EH C2 and EL 0C.
The one that makes no sense until you know
ECC1 on a Midea or ACiQ multi-zone system means the leak alarm came from a different indoor head - another room's unit detected the problem, and your unit shut down in response.
So the head that stopped working may be nowhere near the leak. Chasing the room that went quiet is the wrong instinct: the whole refrigerant circuit is shared, so the whole system is treated as unsafe until a technician verifies the sensor and the circuit. Do not restart the quiet head and assume the noisy one is the problem.
Safe checks — there is only one
Turn the system off at the breaker and leave it off. Ventilate the space. Keep ignition sources away: no smoking, no candles, no gas appliances being lit nearby, no hot work.
That is the entire homeowner list for this class of code. Cleaning filters will not clear a leak alarm, and a power cycle that makes the code disappear has not fixed anything - it has removed your warning.
When to stop and call a technician
Immediately, and for all of these codes.
A2L refrigerant handling is certification-gated - it is not a matter of willingness or tooling. This is true even on systems sold for DIY installation: MRCOOL's line sets are pre-charged and connect by hand, but a leak in the circuit is still a certified-technician job. The install is the DIY part; the refrigerant is not.
Tell whoever you call which code the unit showed. The difference between "the sensor detected refrigerant" and "the sensor itself has failed" changes what they bring and what they check first.
Why this is more common than it used to be
The refrigerant transition is recent. Systems built in the last couple of years use R-32 or R-454B and carry this sensor; older R-410A equipment does not, and has no equivalent code. If you have owned mini splits before and never seen anything like this, that is why - it is new safety equipment doing its job, not a sign that modern systems leak more.
Look your exact code up in the error-code library - the same letters mean different things on different brands - and check what refrigerant your model uses in the database.