Marine · Boat AC & Chillers · CSLB C-20 · EPA 608
Marine Air Conditioning Repair Los Angeles
AC tripping on high pressure, blowing warm or dripping into the cabin? We check the seawater loop first, then the refrigeration. $120 diagnostic, waived with repair.
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Our Branches
10 service territories across Southern California
Marine Air Conditioning Repair
Southern California
01 · The systems
Two kinds of marine air conditioning, one shared weak spot.
A boat in a Southern California slip on an August afternoon needs its air conditioning more than its owner wants to admit. Marine AC comes in two main designs, and our techs diagnose them differently. This page is part of our marine appliance repair service.
Self-contained units
Compressor, coils and blower in one package, usually tucked under a berth, a settee or in a locker, with ducting to the cabin. Smaller boats often run one or two of these, one per zone.
Chilled-water systems
On larger yachts a chiller cools a loop of water that runs to air handlers throughout the boat. One refrigeration plant, many air handlers, more pumps and more controls to go wrong.
We see Dometic equipment, including its Cruisair and Marine Air lines, and Webasto systems. We repair them as an independent service; we're not factory-authorized for any marine AC brand. What both designs share is the way heat leaves the boat: through seawater. That's where most calls end up.
02 · High-pressure shutdown
High pressure is almost always the seawater side.
A marine AC unit pulls heat out of the cabin and hands it to seawater moving through the condenser. When that water slows down, the heat stays in the refrigerant, head pressure climbs, and the unit shuts off to protect itself. From the cabin it looks like the air conditioner randomly quits, often on the hottest afternoon. Our techs work the raw-water loop in order:
- Sea strainer. Packed with growth, shell or debris, it starves the whole loop. It's the first thing we open.
- Water flow at the discharge. A weak or absent stream overboard confirms the loop isn't moving enough water.
- Raw-water pump. A pump that lost its prime, has a worn impeller or has stopped outright gives the same symptom as a clogged strainer.
- Condenser coil. Marine growth and scale inside the coil cut heat transfer even with good flow.
- Refrigeration side. Only after the water side checks out do we put gauges on the refrigerant circuit.
The seacock and the through-hull fitting at the start of that loop aren't ours. If the problem is at the hull, that's boatyard or marine mechanic work, and we'll say so before anyone goes further.
03 · Running but not cooling
When it runs all day and the cabin stays warm.
A unit that runs without tripping but never gets the cabin cool usually has an airflow or refrigerant problem. Clogged return filters and blocked ducting starve the evaporator, which can ice over and cool even less. Low refrigerant from a leak shows up the same way. Salt air speeds up corrosion on coils and fittings, and pinhole leaks follow.
When refrigerant is low, we find and repair the leak before recharging. Opening a refrigerant circuit takes EPA 608 certification, and ours is Universal #1346255700410. We also hold a CSLB C-20 HVAC license. On a boat these aren't wall decorations; they're what makes a sealed-system repair legitimate.
04 · Condensate
Water where it shouldn't be: pans, drains and condensate pumps.
Every air conditioner pulls water out of the air. On a boat that water collects in a drain pan and leaves by gravity or through a condensate pump. When the pan drain clogs, the line kinks or the pump fails, water overflows into the locker, the bilge or the cabin sole. Standing water in the pan also breeds the smell people blame on "the AC".
We clear and flush the drain path, test the condensate pump and its float switch, and check that the pan actually drains before we leave. It's routine work, but a failed condensate pump left alone can soak cabinetry and wiring.
05 · Controls and power
Digital controllers, sensors and the power behind them.
Modern marine AC runs through digital controllers with temperature sensors and fault displays. A failed sensor or a controller that lost its settings can look like a dead unit. We read the controller's fault history where it has one and test sensors before replacing boards.
Power matters too. A compressor start pulls far more current than the running load, and on a generator or an inverter that start can sag voltage enough to trip the unit or stall it. We measure voltage, frequency and polarity at the unit. If the problem is in the boat's own electrical system, the panel or the shore power inlet, the fix belongs to a marine electrician working to ABYC standards, and we'll hand over the readings.
06 · The visit
How a marine AC call works.
Tell us the marina, slip number and how to get through the gate, and make sure the owner, captain or crew is aboard. Let us know whether it's a self-contained unit or a chilled-water system, and send a photo of the data plate and any code on the controller. Everything we bring goes down the dock by hand, so good information saves a second trip.
The diagnostic is $120 and it's waived when you approve the repair. After that you get a written estimate before any part is ordered. If the boat's refrigerator is struggling too, check whether it shares the seawater loop; see marine refrigeration repair.
07 · FAQ
Marine air conditioning questions.
Why does my boat's air conditioner shut down on high pressure?
Because the heat has nowhere to go. A marine AC unit dumps cabin heat into seawater, and when the sea strainer is clogged, the condenser coil is fouled with growth or the raw-water pump isn't moving enough water, head pressure climbs until the unit shuts itself off. We check seawater flow through the loop before we look at refrigerant.
What's the difference between a self-contained unit and a chilled-water system?
A self-contained unit has the compressor, coils and blower in one box, usually under a berth or settee, cooling one area. A chilled-water system uses a chiller to cool a water loop that runs to air handlers around the boat, which is common on larger yachts. Both use seawater to reject heat, so the raw-water side matters on either one.
There's water under my AC unit. Is it leaking refrigerant?
Almost never. Water under a marine AC unit is condensate: the drain pan is blocked, the drain line is kinked or the condensate pump has failed. Left alone it ends up in the bilge or the cabin. Refrigerant leaks don't make puddles; they show up as a unit that runs but doesn't cool.
Are you licensed to work on marine air conditioning refrigerant?
Yes. Opening a refrigerant circuit requires EPA 608 certification, and ours is Universal #1346255700410. We also hold a CSLB C-20 HVAC license and BHGS #A49573. We don't hold ABYC certification and we don't work on the boat's electrical system; that belongs to a marine electrician.
How much is a marine AC diagnostic?
The diagnostic is $120 and it's waived when you approve the repair. You get a written estimate before any part is ordered. We don't publish repair prices for marine AC, because a packed strainer and a failed compressor on a chilled-water system are very different jobs.
08 · Related
More marine service.
Boat AC tripping? Call now.
$120 diagnostic, waived with repair. Mon–Sat 8am–8pm · Sun closed · Phone answered 24/7.