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Mini-Split Repair

Mini-Split Repair in San Antonio

Your mini-split stopped cooling, started leaking, or threw an error code. We diagnose and repair all ductless brands — Mitsubishi, Daikin, Fujitsu, LG, RunTru by Trane — same-day when possible.

Schedule Mini-Split Repair Call (210) 561-COOL

Mini-splits are mechanically simpler than central HVAC systems — fewer moving parts, no ductwork to leak, no blower cabinet. But when they fail, they confuse a lot of general HVAC contractors. The inverter-driven compressor, the electronic expansion valve, the communication protocol between the indoor and outdoor units — these aren't the same components or the same diagnostics as a traditional split system. A tech who's spent his career on Trane and Carrier package units may not know what a Mitsubishi P6 error code means or how to read the LED flash sequence on a Daikin outdoor board. We do.

We've been installing and servicing mini-splits in San Antonio for over a decade, and the volume of ductless work has grown every year as more homeowners discover the advantages. Garage conversions in Alamo Heights, ADUs in Southtown, sunrooms in Stone Oak, home offices across the north side, older homes in Monte Vista and Dignowity Hill that never had ductwork — mini-splits are everywhere now, and they need technicians who understand the technology. We work on every major ductless brand: Mitsubishi, Daikin, Fujitsu, LG, Samsung, Gree, and RunTru by Trane. If it's mounted on a wall and connected to a condenser by a line set, we can fix it.

Most mini-split repairs are straightforward once you know where to look. The challenge is that error codes and symptoms overlap — a blinking light on the indoor unit could mean a dozen things depending on the brand, model, and sequence. We carry the diagnostic tools specific to ductless systems, including manometer sets for checking static pressure on ducted mini-split cassettes and brand-specific service software for reading onboard diagnostics. We don't guess. We read the data, isolate the fault, and fix it.

Why Choose Our Mini-Split Repair Service

All ductless brands serviced — Mitsubishi, Daikin, Fujitsu, LG, Samsung, Gree, RunTru by Trane, and more. We don't turn away off-brand units.

Same-day service available. Mini-splits often serve a single room — when they go down, that room is unusable. We prioritize accordingly.

Inverter board and control diagnostics. We carry the tools and training to troubleshoot variable-speed compressors and communication errors, not just swap parts.

Upfront pricing before work begins. You approve the cost, or we don't touch it. Diagnostic fee applies toward the repair if you move forward same day.

1-year warranty on all repairs. If the same component fails within 12 months, we come back at no charge.

Refrigerant leak detection and repair. Mini-splits use small-diameter copper or aluminum line sets that are more susceptible to vibration cracks. We locate and fix the leak — not just recharge and hope.

Mini-Split Problems We See Regularly in San Antonio

Ductless systems are reliable, but San Antonio's heat, humidity, and dust create specific failure patterns. These are the calls we run most often.

Water Leaking from the Indoor Unit

The most common mini-split complaint in San Antonio. High humidity means the evaporator coil produces a lot of condensate. The drain line from the indoor unit clogs with dust and algae, and water backs up into the drain pan and overflows down your wall. We clear the line, treat it with anti-algae solution, and check that the unit is still level — a unit that's shifted even slightly can cause chronic drainage issues. Typical cost: $150–$300.

Error Codes / Blinking Lights

Every ductless brand has its own error code system. Mitsubishi uses alphanumeric codes on the remote display. Daikin and Fujitsu use LED blink sequences on the indoor unit. LG shows codes on the wired controller. These codes point to everything from a thermistor failure to a communication error between indoor and outdoor units. We carry the reference materials for every major brand and use manufacturer diagnostic software where available. Don't ignore error codes — they rarely clear themselves.

Unit Not Heating or Cooling

If the fan runs but the air isn't conditioned, the most common causes are low refrigerant, a failed inverter board, or a stuck electronic expansion valve (EEV). On heat pump mini-splits, a stuck reversing valve can also lock the system in one mode. We check refrigerant pressures, electrical readings, and board outputs to isolate the fault. Unlike central systems, mini-split compressors modulate speed — a partially failed inverter can make the system seem like it's working but at a fraction of its capacity.

Foul Smell When the Unit Runs

San Antonio's humidity creates the perfect environment for mold and bacteria to grow on the evaporator coil and blower wheel inside the air handler. You'll notice a musty or sour smell when the unit kicks on. This requires a deep clean — removing the blower wheel, cleaning the coil with a biocide, and flushing the drain pan. A filter cleaning alone won't fix it. We recommend this service annually in our climate.

Outdoor Unit Not Starting

If the indoor unit runs but the outdoor compressor doesn't engage, it's usually an inverter board failure, a blown fuse on the outdoor control board, or a communication wiring issue between indoor and outdoor units. Mini-split communication runs on a 2- or 3-wire signal cable that can be damaged by rodents, UV exposure, or a loose connection at the terminal block. We test the signal voltage and trace the wiring to isolate the fault.

Refrigerant Leak

Mini-splits use pre-charged line sets or field-brazed copper connections. Vibration from the compressor, thermal expansion at flare fittings, and corrosion from coastal humidity (less common in SA, but it happens) can cause slow leaks. Symptoms: gradual loss of cooling capacity, ice forming on the line set, or the system cycling on high-pressure cutout. We use electronic leak detectors and nitrogen pressure testing to find the leak, repair it, pull a vacuum on the system, and recharge to factory spec.

Unusual Noises — Rattling, Buzzing, Clicking

Mini-splits are supposed to be whisper-quiet. If yours is rattling, the wall mount may have loosened or the blower wheel is out of balance from dust buildup. Buzzing from the outdoor unit usually points to a failing capacitor or loose refrigerant line vibrating against the cabinet. Clicking at startup can be a relay issue on the inverter board. A high-pitched whine sometimes means the fan motor bearings are wearing. None of these resolve on their own — and a rattling mount left alone can crack the drain pan, turning a $150 fix into a $300 water damage call.

What to Expect

You call, we schedule. If your mini-split serves your only cooled space — a garage office, a converted room — we treat it as urgent. We give you a 2-hour arrival window.

Our technician checks the indoor unit first: error codes, drainage, filter condition, coil cleanliness, thermistor readings, and blower operation. Then the outdoor unit: compressor amps, inverter board status, refrigerant pressures, and wiring integrity.

We read the system's onboard diagnostics. Most mini-splits store fault history — the last several error codes and when they occurred. This tells us if you have a recurring issue or a one-time fault.

We explain what we found and give you a price before any work starts. If the repair doesn't make financial sense — for example, an inverter board on a 12-year-old unit that costs as much as a new system — we'll tell you honestly.

We complete the repair, run the system through heating and cooling modes, and verify that all temperature readings and pressures are within spec. We also check drainage under load to make sure the condensate issue won't recur.

Before we leave, we note any maintenance items that could prevent future problems — dirty filters, outdoor coil blockage, line set insulation deterioration. Preventive info, not a sales pitch.

Mini-split repairs typically cost $150–$800 in San Antonio.

Drain cleaning and minor electrical on the low end. Inverter boards and refrigerant leak repairs on the high end. Diagnostic fee of $89–$250 applies toward the repair.

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Frequently Asked Questions

Most mini-split repairs fall between $150 and $800. A condensate drain cleaning or filter issue is $150–$250. A thermistor or sensor replacement runs $200–$400. Refrigerant leak repair with recharge is $400–$700. An inverter board replacement is the most expensive common repair at $500–$800, though on some brands the board alone costs $400+ as a part. We charge a diagnostic fee of $89–$250 that gets applied to the repair total if you move forward the same day.

Yes. We service Mitsubishi, Daikin, Fujitsu, LG, Samsung, Gree, RunTru by Trane, and other ductless brands. The diagnostic approach is similar across brands, but error codes, board layouts, and parts are brand-specific. We carry the most common replacement parts — thermistors, drain pumps, capacitors, fan motors — and can source brand-specific boards within 1–2 business days for less common units.

Turn the unit off to prevent further water damage, then call us. Water leaking from the indoor unit is almost always a clogged condensate drain line. In San Antonio's humidity, these lines clog with algae and dust faster than in drier climates. Don't try to poke a wire into the drain port — you can push the clog deeper or damage the drain pan. We clear the line properly, treat it with anti-algae solution, and verify the unit is still level on its mounting plate. If the unit has shifted, drainage will be chronic until it's re-leveled.

Every brand uses a different system. Mitsubishi displays alphanumeric codes (P6, E6, U4, etc.) on the remote or wired controller. Daikin and Fujitsu use LED blink patterns on the indoor unit — for example, a green light blinking 7 times then pausing indicates a specific fault. LG shows codes on the wired controller display. The owner's manual usually has a basic code chart, but many codes require diagnostic equipment to interpret. If your unit is showing an error and won't clear after a power cycle (breaker off for 30 seconds, then back on), call us. Running the system with an active fault code can cause secondary damage.

No. A musty or sour smell means mold or bacteria is growing on the evaporator coil and blower wheel inside the air handler. This is extremely common in San Antonio because of our humidity levels. The fix is a deep clean — we remove the blower wheel, chemically clean the coil and fan, flush the drain pan, and treat everything with a biocide. A surface-level filter cleaning won't solve it. We recommend annual deep cleaning for any mini-split in our climate. Between cleanings, running the unit in fan-only mode for 30 minutes after cooling helps dry the coil and slow mold growth.

Mini-splits typically last 12–15 years with proper maintenance. If yours is under 8 years old, repair almost always makes sense. Between 8 and 12, it depends on the repair cost — if a single repair exceeds 40–50% of a new unit's price, replacement is worth discussing. Over 12, especially if it's had multiple repairs, a new unit with current inverter technology will be more efficient and more reliable. We'll give you both numbers and let you decide.

We can, but we won't just top it off and leave. Mini-splits are sealed systems — if you're low on refrigerant, you have a leak. Adding refrigerant without finding and fixing the leak is a waste of money. The charge will leak out again in weeks or months, and running a system low on refrigerant damages the compressor over time. We locate the leak, repair it, pull a vacuum to remove moisture and air from the system, and then recharge to the manufacturer's exact specification. It costs more upfront than a simple recharge, but it actually solves the problem.

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Schedule Service Call (210) 561-COOL