Marine AC Flush
& Descaling Service

A marine AC flush — also called descaling — is the process of circulating a chemical descaling solution through the seawater side of a boat's air conditioning condenser. The solution dissolves calcium carbonate, mineral scale, and salt deposits that restrict water flow and reduce cooling efficiency. In Southwest Florida's warm, mineral-rich saltwater, this is the single most important AC maintenance task.

A professional marine AC descaling flush costs $200–$400 per unit in Southwest Florida, depending on unit size, access difficulty, and severity of scale buildup. Multi-unit vessels get volume pricing. Accumar Marine's maintenance plan members pay a flat per-visit rate of $140. Compare that to the $1,500–$3,500 cost of a compressor replacement caused by neglected scale — the flush pays for itself many times over.

In Southwest Florida: every 12 months minimum for seasonal boaters. Liveaboards running AC year-round should flush every 6–8 months. Boats docked in canals with hard water or near construction runoff may need more frequent service. The spring pre-season flush is the most critical — it clears scale that accumulated over winter and ensures your system is ready for the heat.

You can attempt a DIY flush with white vinegar, but it's only about 20% as effective as professional-grade descaling solution. Vinegar (5% acetic acid) struggles to dissolve hardened calcium carbonate deposits. Accumar Descaling Solution is formulated specifically for marine heat exchangers and works 5x faster. A professional flush also includes impeller inspection, strainer service, and refrigerant check — issues a DIY flush won't catch.

We use Accumar Descaling Solution — our own proprietary formula developed through 30+ years of marine AC service in Southwest Florida. It's a phosphoric acid-based solution that dissolves calcium carbonate and mineral scale without damaging copper, cupronickel, or titanium heat exchangers when used as directed. Available for purchase in quart ($20), gallon ($66), and 5-gallon sizes for boat owners who want to supplement between professional services.

A single-unit descaling flush takes 45–90 minutes depending on scale severity. The solution circulates through the condenser for 30–60 minutes while we monitor pH levels — when the pH stabilizes, the scale is dissolved. Multi-unit vessels take 2–4 hours. We perform the service at your dock — no need to haul the boat.

Scale buildup is progressive and cumulative. Year 1: 10–20% efficiency loss, slightly warmer air. Year 2: 30–50% loss, system cycles on and off (high-pressure lockout). Year 3+: compressor failure from chronic overheating. A $200 annual flush prevents a $2,000–$3,500 compressor replacement. In SWFL's 80–87°F seawater, skipping even one year of flushing is a gamble.

Warning signs: (1) AC blows less cold than last season, (2) system runs constantly without reaching set temperature, (3) AC cycles on and off every few minutes (high-pressure lockout), (4) weak overboard discharge flow, (5) system hasn't been flushed in 12+ months. If you notice any of these, call 239-323-9600 — we can usually diagnose over the phone and schedule same-day service.

We flush and service many Dometic, Marine Air, Cruisair, Webasto, Climma, Mermaid, Flagship, Condaria, Frigoboat, and other marine A/C installations. The procedure depends on access points, condenser materials, system layout, and manufacturer guidance; service scope is confirmed from the installed equipment.

Yes. The AC & Refrigeration Seasonal Service plan includes descaling flush, coil cleaning, refrigerant check, seawater pump inspection, thermostat calibration, and strainer service — twice per year (spring and fall). Starting at $295 for a single unit. Plan members also get priority scheduling and no emergency call-out fees. It's the most cost-effective way to keep your marine AC running in Florida.