Why is my boat AC blowing warm air?

The most common cause in Southwest Florida is calcium scale buildup inside the condenser heat exchanger. SWFL's warm saltwater (80-87°F) accelerates mineral deposits that restrict water flow. Other causes: clogged raw water strainer, worn seawater pump impeller, low refrigerant from a leak, failed compressor, or faulty thermostat. A professional descaling flush resolves 70%+ of 'not cooling' complaints same-day.

How much does it cost to fix a boat AC that's not cooling?

It depends on the root cause. A descaling flush runs $200-400 and fixes most cases. Impeller replacement is $150-300. Refrigerant leak repair and recharge is $400-800. Compressor replacement is $1,500-3,500 depending on the unit size and brand. We always diagnose first and give you a written estimate before starting any repair. Call 239-323-9600 for a free phone consultation.

My boat AC worked fine last year but now it's not cooling — what happened?

Scale buildup is cumulative. In SWFL's warm, mineral-rich saltwater, 12 months of operation deposits enough calcium to reduce condenser efficiency by 30-50%. Systems that sat idle over winter are worse — stagnant saltwater accelerates corrosion and scale hardening. An annual descaling flush before summer prevents this completely.

Can I flush my boat's AC system myself?

You can do a basic vinegar flush, but it's only about 20% as effective as professional descaling. Professional-grade descaling solutions (like Accumar Descaling Solution) are formulated specifically for marine heat exchangers and dissolve calcium carbonate 5x faster than household vinegar. We also inspect the impeller, strainer, and refrigerant charge during the service — issues a DIY flush won't catch.

How often should I flush my boat's AC in Florida?

In Southwest Florida: every 12 months minimum. Liveaboards running AC 10-12 months/year should flush every 6-8 months. Boats in canals with hard water may need more frequent service. The cost of an annual flush ($200-400) is a fraction of the $2,000-3,500 compressor replacement that neglected scale buildup causes.

My boat AC cools for a while then stops — what's wrong?

This is classic high-pressure lockout. The compressor runs until head pressure exceeds the safety limit, then the high-pressure switch shuts it down. After it cools, it restarts — and the cycle repeats. The root cause is almost always restricted water flow: scale in the condenser, worn impeller, clogged strainer, or partially blocked thru-hull. Left unchecked, the repeated thermal cycling destroys the compressor.

Is it worth repairing an old marine AC unit or should I replace it?

General rule: if the compressor is good and the unit is less than 15 years old, repair is usually more cost-effective. If the compressor has failed on a unit older than 12-15 years, replacement often makes more sense — newer units are 20-30% more efficient and quieter. We'll give you an honest assessment. We don't push replacements when a $300 repair will get you 5+ more years.

Do you offer same-day boat AC repair?

Yes — for most common issues (flush, impeller, strainer, thermostat), we can often diagnose and repair same-day. We carry common parts on our service vehicle. For compressor replacements or major repairs, we typically need 1-3 days for parts. Call 239-323-9600 — we'll tell you upfront what to expect.

ACCUMARMarine Services

239-323-9600

MOST COMMON MARINE AC COMPLAINT IN SWFL

Boat AC Not Cooling?
We Fix It Same-Day.

70% of "not cooling" calls are caused by scale buildup in the condenser. A professional descaling flush restores full cooling — usually in under 2 hours, at your dock.

Fort Myers, Cape Coral, Naples, Sanibel, Marco Island & all of Southwest Florida

Call 239-323-9600

Why Your Boat AC Stopped Cooling

Ranked by frequency in Southwest Florida — based on 25+ years of service data

Scale Buildup in Condenser

45% of cases

SWFL's warm saltwater (80-87°F) deposits calcium carbonate inside the heat exchanger, restricting water flow and reducing heat rejection. The #1 cause by far.

Professional descaling flush — $200-400, same-day

Worn Seawater Pump Impeller

20% of cases

Rubber impeller vanes wear, crack, or break off over time. Reduces seawater flow through the condenser even when the strainer is clean.

Impeller replacement — $150-300, same-day

Low Refrigerant (Leak)

15% of cases

Vibration and corrosion cause refrigerant leaks at fittings, flare connections, or the evaporator coil. System runs but can't reach target temperature.

Leak detection, repair & recharge — $400-800

Electrical / Thermostat Failure

10% of cases

Failed thermostat, bad capacitor, corroded wiring, or tripped breaker. System may not start at all, or may run continuously without cycling.

Electrical diagnosis & repair — $150-500

Compressor Failure

10% of cases

Usually the end result of ignoring the problems above. Compressor overheats from restricted flow, loses efficiency, and eventually seizes.

Compressor replacement — $1,500-3,500

Don't ignore reduced cooling — it gets worse fast

A $200 flush today prevents a $3,000 compressor replacement next month. Scale buildup is progressive — every week you wait, it gets harder and more expensive to fix.

How We Fix It

Most "not cooling" issues resolved same-day at your dock

Diagnose

We measure seawater flow, refrigerant pressures, amp draw, and supply air temperature. No guessing — data tells us exactly what's wrong.

~30 min

Repair

Descaling flush, impeller replacement, refrigerant recharge, or electrical repair. We carry common parts on our service vehicle for same-day fixes.

~1-2 hrs

Verify

We run the system and measure performance after repair. You get cold air and documented proof that the system is operating within spec.

~15 min

Common Questions

Boat AC Not Cooling — Common Questions

Get Your Boat AC Cooling Again — Today

Accumar Marine Services — 25+ years fixing marine AC in Southwest Florida. EPA 608 certified. All brands.

Same-Day Service Available • Mobile to Your Dock • Free Phone Consultation