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Cooling & Heating · Ductless RepairDuctless Mini-Split Repair
Ductless mini-split repair starts with the error code: the blinking light on the head or the code on the remote names the sensor, board or communication link the unit has lost. Most repairs fall in the $150–$800 range after a $90–$150 diagnostic. The exception is an outdoor inverter board or a compressor on a unit past ten years, where replacement is usually the better spend.
A mini-split is not a small central air conditioner. Its compressor and both fans are variable-speed, driven by an inverter board in the outdoor unit, and the indoor and outdoor units signal each other continuously over a control wire. So the common faults are electronic: a communication error (LG shows it as CH05, Daikin as U4), a failed thermistor, a dead fan motor or the inverter board itself. Codes differ by brand and model, the guides under brands list them, and the manual for your model has the final word.
A communication error is a wiring fault more often than a board fault. The cable between the two units carries power and signal together, and a splice in that cable, a loose terminal, a corroded connection or insulation chewed by mice interrupts the signal. We check voltage and continuity at both terminal blocks before condemning either board. Thermistors are tested the same way: each sensor's resistance should match a temperature chart, and one that reads off is a small part, not a new unit.
Water dripping from the indoor head has three usual causes. The drain is blocked with slime, the condensate pump on an interior-wall installation has failed, or the head was hung out of level so the pan tips away from its outlet. A fourth cause is ice: a unit low on refrigerant or starved of air freezes its coil and then sheds meltwater past the pan. Why a mini-split leaks water inside helps you tell them apart before you call.
Refrigerant leaks on ductless systems are nearly always at the flare joints made on installation day. A flare that was over-tightened, under-tightened or formed with the wrong tool seeps slowly, and the symptom arrives two to five years later as weak cooling or frost at one end of the coil. The repair is to recover what charge is left, cut and remake the flares, pressure-test with nitrogen, evacuate and weigh in the exact charge on the nameplate. Mini-splits are charged by weight; topping one up by gauge pressure is guesswork.
Call for mini-split repair when
- The operation or timer light blinks in a repeating pattern, or the remote shows a code
- Water drips from the bottom of the head or runs down the wall
- The head runs but the air is room temperature in cooling or in heating
- The outdoor unit is silent, or starts and stops every few minutes
- One head on a multi-zone system has quit while the others work
How it works
Note the blink pattern or the code, and the model number from the label under the head or on the outdoor unit. Switch the breaker off for five minutes and back on once. A reset that clears the code is useful information, but do not keep cycling the power; then call or message us.
The code narrows the search and the meter finishes it: cable continuity, sensor resistance, motor windings, board outputs. You get the fault in plain language and a written price before a part is ordered.
The part is fitted, the unit is run in heating and in cooling, and the temperature change across the indoor coil is measured. Where a flare was remade, the nitrogen test pressure, vacuum reading and charge weight go on the invoice.
Brands: We repair Mitsubishi, Fujitsu and Daikin ductless systems and see LG, Gree, Samsung and Senville heads as well; parts supply for the first three is the most dependable.
Common questions
Do you repair mini-splits you did not install?
Yes. It makes no difference who installed the system, and that includes builder-installed and online-purchased units. For budget brands sold online, sensors and fan motors can usually be found, while a discontinued inverter board can end the repair. We check parts availability for your model number before quoting, so you are not paying for a diagnosis that leads nowhere.
Is it safe to keep running a mini-split that shows an error code?
If it has shut itself down, leave it off; the lockout is protecting the compressor. If it still runs but drips water or blows weak air, turn it off to prevent water damage or a frozen coil. A code that clears after one breaker reset and stays away can be watched. Why a mini-split light blinks covers the patterns.
When is a mini-split not worth repairing?
When the fault is the outdoor inverter board or the compressor, the unit is past ten years old, and the repair exceeds half the price of a new single-zone system. Under ten years, or for sensors, fan motors, drains and flare leaks, repair is nearly always right. Ductless mini-split installation describes what a replacement involves.
Why does only one head on my multi-zone system not work?
Start with that head's own parts: its thermistors, its fan motor, or the electronic expansion valve in the outdoor unit that feeds it. A mode conflict is the other cause, because a head asked to cool while the rest are heating will sit idle. Why one mini-split head is not working walks through the checks.
Can a power surge damage a mini-split?
Yes, and the inverter board is what it damages. Storm-season surges and brownouts are a common story behind a unit that ran yesterday and is dead today. A surge protector at the outdoor disconnect, fitted by a licensed electrical contractor, is inexpensive protection for the board. Check your home insurance too, since surge damage is sometimes covered.