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Discussion Starter · #1 ·
Hi,

I have a problem I like to get your advice on. I have a 1978 Pearson 323 with air-conditioning. The air-conditioning unit was installed by the previous owner, so I have no idea how old the unit is. It is a standard 120 V system which runs only on shore power. The air conditioner will run for about 10 minutes and then the circuit breaker will turn off. If I wait for a minute or two and reset the breaker, the unit will run for a much shorter period of time before the breaker turns off again.

Because of the location of the shore power I have no choice but to run two standard 30 amp power cords connected in series. I thought that the breaker might be weak because of its age, so I replaced it with a new 20 amp breaker identical originally installed. Unfortunately this did not solve the problem. When the compressor turns on the amp meter momentarily kicks up to between 15 to 18 A but then drops down to the normal draw of approximately 10 – 11 A. The onboard voltmeter shows an input of 120 V. My next step is to replace the onboard receptacle, although there are no obvious signs of corrosion or burning. But before I proceed I would like to get your thoughts on correcting this problem.

Thanks in advance.
 

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islander bahama 24
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Try a 30 amp breaker in the shore power line but only if you have boat side breaker protection on the branch line that feeds the ac unit sounds to me like you have a high loss due to length of shore power cables however don't leave unattended during the power test and check everything three times JM 2¢ worth
 

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██▓▓▒▒░&
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An old (20-25 year old?) air conditioner probably has lost Freon. This results in the compressor running overtime and drawing too much current trying to compress "air" in the system instead of Freon. If the air conditioner doesn't have an internal breaker, the overload may throw your line breaker. They can do that (overload) for other reasons as well.

I'd suggest putting an ammeter in the circuit (a clamp meter or anything that can read 20-40 amps such as one of the "Kill-a-watt" AC gizmos) to see just how much power the air conditioner is drawing. If it is over the rated power, look to replacing it, as servicing them is usually more expensive and less reliable than replacing.
 

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Freedom 39
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I am not sure what a "standard 120v" air conditioner is. If it is water cooled, or supposed to be, do you have good water flow? Is the circulation pump running? Strainer clogged? Seacock closed? If it's an air cooled unit is it hard wired into your boat or run off of a cord? If it is run off a cord does the cord get warm near the receptacle it's plugged into? Does the unit put out cold air before it trips a breaker? What is the manufacturer? More info would help troubleshooting via the internet.
As HelloS said above, unless it is something very simple, it will probably make more sense to replace the unit with something newer and more efficient.
 

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Generally when motors and stuff get old it takes more energy to turn worn parts,. This shows up as internal heat and causes things like fuses or built in thermo safety switches tell you they're not happy. Piss them off enough and they burst into flames of displeasure.
 

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Discussion Starter · #6 ·
To clarify: 120v-not 240v. Water cooled, reverse cycle (heats as well as cools) yes, good water flow. Circulation pump is running. Strainer does not seem to be clogged as water flow is good ditto for the seacock not being closed. Unit puts out cold air before the breaker trips. Could the air conditioner draw more amps by itself than the 10 amps indicated on the onboard volt meter? I don't know off hand what the unit is suppose to draw, but I will check the next time I am at the boat.Yes, the power cord does get warm at the boat receptacle, which is why I was wondering if that is where the problem is.

Thanks for your interest.
 

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██▓▓▒▒░&
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"To clarify: 120v-not 240v. Water cooled, "
Oh, then it is not a "standard" air conditioner at all. Like you buy for $99 in the ads in the Sunday paper and then stick on a boat.
It's a standard water-cooled marine air conditioner.

And the water cooling system is the first thing to suspect. Check th eflow and if there's any doubt about it, try using a garden hose and cooling it "for sure" to see if it keeps running. Old water cooling or pumps are likely to be problems.
 

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Old as Dirt!
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Hi,

I have a problem I like to get your advice on. I have a 1978 Pearson 323 with air-conditioning. The air-conditioning unit was installed by the previous owner, so I have no idea how old the unit is. It is a standard 120 V system which runs only on shore power. The air conditioner will run for about 10 minutes and then the circuit breaker will turn off. If I wait for a minute or two and reset the breaker, the unit will run for a much shorter period of time before the breaker turns off again.

Because of the location of the shore power I have no choice but to run two standard 30 amp power cords connected in series. I thought that the breaker might be weak because of its age, so I replaced it with a new 20 amp breaker identical originally installed. Unfortunately this did not solve the problem. When the compressor turns on the amp meter momentarily kicks up to between 15 to 18 A but then drops down to the normal draw of approximately 10 – 11 A. The onboard voltmeter shows an input of 120 V. My next step is to replace the onboard receptacle, although there are no obvious signs of corrosion or burning. But before I proceed I would like to get your thoughts on correcting this problem.

Thanks in advance.
It would be helpful to know the make of the AC Unit. When you purchased the boat, I suspect the seller may have included quite a file of "Ship's Papers" that may include the paperwork on the AC. If not, you might contact the Seller to see if he/she may still have anything, or remembers the name/date of the machine. Alternately, if you have access to the machine the makers name will likely be listed on a placard somewhere.

N'any case, based upon my own similar experience I suspect you may have a build-up of debris in the heat exchanger that is preventing the machine from shedding heat to the raw water. If you have one, an infrared thermometer will let you measure the temperature difference between the intake water and discharge water. On our 16,000 BTU unit, for example there is about a 12º or greater temperature rise in the discharge water. If not, the flow may not be sufficient causing a steady temperature rise in the compressor circuit, making the compressor overwork and draw greater amperage until it blows the circuit. The same could be true if you are low on freon but, if so, you would likely find ice forming on the radiator grid that actually cools the air which could also lead to a high temp/high pressure failure in the compressor. Cleaning out the heat exchanger coils is not a difficult job and there are several threads here abouts that describe the methods. Replacing freon will be a job for a technician unless you have those skills.

I note that you are located in Southwest Florida. If in the Tampa Bay area, there are several good AC mechanics that might be able to assist you, if necessary.

FWIW...
 

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Freedom 39
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Ok Boomer we are getting nearly enough info now. A manufacturer, BTU rating or any other nameplate data would be helpful. My old 16k BTU unit draws right at 10 amps when running. Some newer units seem to be a little more efficient. Assuming you have a 30 amp cord it should NOT be getting warm with only a 10 amp load on it where it plugs into your boat. Have you unplugged the cord and looked at it and the receptacle on you boat it attaches to? Is it discolored or corroded looking? Are you running anything else at the same time? Water heater? Battery charger? Someplace on your AC unit it brings air in, is it filthy dirty there? The place I'm describing will look like a miniature car radiator. Is there any kind of an air filter or something blocking the air intake? The compressor will look like a small tank roughly the size of a plastic gallon jug but made of metal. Put your hand on it when you start the unit. Does it get hot instantly? Too hot to touch before the breaker trips? You say you have good water flow. Is it shooting well out of the thru hull or just running down the side of your boat? Can you get your hand on that water flow and see how warm it is coming out?
 

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Discussion Starter · #12 ·
Thanks to all of you who replied to my question. I went to the boat today specifically to work on the air-conditioning using your suggestions. The results are as follows:

1 – The first thing I did (after plugging in the shore power which I normally disconnect when I am not at the boat) was to turn on the 120 V heating element in the water heater. I almost never use this, but I wanted to see if its breaker would trip indicating a possible low-voltage issue with the shore power itself. The heating element draws about 10 A while the air-conditioning draws about 12 A. The breaker did not trip!
2 – The next thing was to check the air filter which turned out to be pretty dirty. It is the coarse aluminum strand type which I thoroughly washed out with water. I also cleaned off the heat exchanger itself as best as I could. Feeling confident I had solved the problem I turn the air conditioner on. It ran for its usual 10 minutes or so and then tripped the breaker again.
3 – Even though I observed a good flow of water exiting the boat, I removed and checked the in-line filter in the water line. I had cleaned it not too long ago, and it was virtually spotless. So I doubt that this is the problem.
4 – I then removed the panel where the three air-conditioning control knobs are. The first one is the selector switch for off, fan only, heat, and cool. The next one is for controlling the speed of the fan. And the last one is the thermostat. One of the spade connectors on the first switch was badly discolored indicating that it was overheating. I cleaned off the male spade connector coming off the switch with a little sandpaper even though it did not seem to be particularly tarnished, spliced in a new piece of wire with a new female spade connector, and attached it to the terminal. I was now sure I found the problem. I turned on the air conditioner and once again it popped the breaker.

After working in the heat down here in Southwest Florida, I was pretty much beat for the day. So I dug out the original paperwork and came home. It turns out unit I have was manufactured by KING-AIR, and was purchased in June 1990. I looked them up on the Internet and found that they are still in business. I called them up and a young lady answered the phone and said she could not help me but you would have someone return my call in about 20 minutes. Sure enough 20 minutes later the phone rang (and get this) it was the owner calling me back. After discussing the matter, he feels the problem is either a bad capacitor or some loose wiring. He suggests that I open up the wiring compartment which is a small metal box located next to the compressor. He thinks I should be able to see the cause of the problem and fix it myself, however if I am unable to do so, all I have to do is remove the whole unit and send it back to him. He will repair it and guarantee his work. How’s that for standing behind a product!

Thanks again for all your input, and I’ll keep you posted as things progress.
 

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He thinks I should be able to see the cause of the problem and fix it myself, however if I am unable to do so, all I have to do is remove the whole unit and send it back to him. He will repair it and guarantee his work. How’s that for standing behind a product!

Thanks again for all your input, and I’ll keep you posted as things progress

____________________

And where happened? Did you send it back?
 

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Discussion Starter · #14 ·
Sorry for the delay in responding to your question, but I’ve been trying various things to get the air conditioner working. Unfortunately, none of them have been successful. After a few more phone calls with the factory the best guess now is that the windings in the motor in the compressor have deteriorated, and as the compressor heats up the wires are shorting out to the housing or to each other. Once again the manufacturer has offered to have me send back the unit for a rebuild, but if the compressor needs to be replaced we are probably talking in the neighborhood of $1200 plus freight back and forth. A new unit would be approximately $2100. But as I use the air conditioner so infrequently the cost to benefit numbers simply don’t make sense for me. So as it stands now, I will simply leave everything in place, and leave it to the next owner whoever they may be to decide if a repair or replacement is worth it to them.
 
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