Barnacled air conditioning popping breaker

[bobbyp]

Kind of new to warm water boating and left the air conditioning on for over 2 months.
Got back to a miserably barnacle clogged sea strainer and the air conditioning circuit breaker off.

Turning it back on, it just pops the circuit breaker within 5 seconds - right after the compressor starts making a sound.
Raw water pump (PMA1000C) doesn't do anything in those 6 seconds though I'm not sure it is supposed to.

It is a Marinair circa 2002, I think 30k btu (marked Csp30rz).

I got some barnacle buster to try to clean out the system.
Any other suggestions for anything else to look at? Was supposed to head to the keys or Bahamas next week.

Thanks and happy holidays to all.

 

[Capecodder]

Try turning the power off a the breaker for a few minutes and see if she resets.

 

[RT Firefly]

Greetings,
Mr. bp. It won't hurt to flush the system with Barnacle Buster (BB). As I understand it, you disconnect the input and output hoses from the thru-hulls and use a bilge pump to circulate the BB out of a bucket. Flush in the opposite normal direction of the flow, I think.


I also think BB is phosphoric acid and you can buy it in concentrate as acid concrete wash. Much cheaper. ($12/ qt. at Home Despot). Dilute to BB concentrations.

 

[STB]

A stopped motor or pump, depending upon the type, can draw dramatically more current than a running one. So, if growth is preventing the normal spin up, current could be very high much longer and can throw a breaker.

In addition to the existing suggestions, e.g. barnacle buster, if your pump has an impeller, inspect it and the impeller well and ensure the shaft moves freely.

 

[bobbyp]

The last diagnostic code appears to be AAA which means a bad temperature sensor. Which kind of makes sense since, in the brief time it stays on it displays either 256 or 0 degrees. According to the manual, the system will not run with a bad temp sensor.
Now that the system is semi cleaned out I will look into replacing the NLA panel that includes the temperature sensor.

 

[Russell Clifton]

I would think the thru hull could also be plugged. A diver could clean it out.

 

[Newtrawlerowner]

I had a similar issue on my sailboat. I closed the thru-hull, removed the hose, using a long (14") screw driver I opened the thru-hull and pushed the screwdriver through several times to clean the clog. One time I found a plastic bag had gotten sucked into the thru-hull.
Either way this will save a diver fee.
If the issue is a plugged raw water pump, you could disconnect the power to the pump and try the breaker. If it comes on now, the pump is restricted or seized. On mine the pump could be removed from the motor, so that's what I did.

The code sets when no cooling water to the heat exchanger.



You could also try a dock-side water hose plumbed to the raw water pump or even directly to the heat exchanger.

 

[bobbyp]

Diver was there a couple of days ago and said everything is clear.

Also had an air conditioning guy over for a look and he says it is a failed compressor.

This is a 17 year old MarinAirrrrr split system with a 30k btu compressor unit, a 12k btu blower, another 12k btu blower and a 6k btu blower and the older design Passport II control. Sorry if I am using the wrong terms.

AC guy gave a quick estimate and says a new compressor is $3k plus whatever time/$ it takes him to install. A new complete unit is $7k plus a little less time/$ to install. The AC guy is independent but seems like a straight shooter. Does this seem reasonable?

Currently in central Florida but heading south without AC on Saturday for a couple of weeks. Any online second opinions from the TF crowd or any recommendations for second opinions along my route south?

This is definitely the not-fun part of boating.

 

[siestakey]

Diver was there a couple of days ago and said everything is clear.

Also had an air conditioning guy over for a look and he says it is a failed compressor.

This is a 17 year old MarinAirrrrr split system with a 30k btu compressor unit, a 12k btu blower, another 12k btu blower and a 6k btu blower and the older design Passport II control. Sorry if I am using the wrong terms.

AC guy gave a quick estimate and says a new compressor is $3k plus whatever time/$ it takes him to install. A new complete unit is $7k plus a little less time/$ to install. The AC guy is independent but seems like a straight shooter. Does this seem reasonable?

Currently in central Florida but heading south without AC on Saturday for a couple of weeks. Any online second opinions from the TF crowd or any recommendations for second opinions along my route south?

This is definitely the not-fun part of boating.

What part of Central Florida are you if your near by I can take a look not that I am an expert but I have sure been through the same

 

[Dougcole]

If you are near the Stuart area maybe take a look at Ocean Breeze. I had two of their units in our old boat and they were great. A little less expensive as well.

 

[bobbyp]

Thanks all. Currently in Daytona but plan on getting in a trip before my son has to get back to college on th 14th so will be leaving without AC tomorrow morning for a few weeks. This will give me some time to decide on what to do and where to get it done anywhere between Daytona and Miami.

siesta key - Many thanks, your offer is extremely generous and shows why the community around this forum is so great.

 

[Duvie]

Compressor

Bobbyp, my experience is that you need to be very careful with diagnosis's made by an HVAC tech. Some are very good but many others lack the proper troubleshooting knowhow and end up unnecessarily replacing parts.

I am a self taught maintenance/HVAC tech. I complete 95% of preventative maintenance and repairs in house and will occasionally hire outside vendors to complete work when we are busy with other things.I work on units from small refrigeration units up to 40 ton packaged roof tops. This is where I get the above experience.

The last unit I worked on was a commercial reach in cooler. I had one of my guys look at it and he said the box was warm because it was in the defrost mode. Later I inspected the unit myself and it was immediately obvious that the compressor was not starting (you could hear the fans slow and see the lights dim when it tried to start until it tripped the compressor internal overload). I tested the start capacitor for the compressor with a multimeter and it tested bad. Replaced that capacitor with one I had on the shelf and the unit was back up and running.

So you really need to ask the tech how he determined the compressor was bad. It could be as simple as a 20 dollar start capacitor or on the other end of the spectrum it could be an open or shorted compressor.

I looked up Copeland compressors on supplyhouse.com in the size range that you have. Locked rotor current in that size unit shows to be around 80 amps and would certainly trip your breaker (a bad start capacitor creates a locked rotor situation). Pricing for units in that range was around $800 dollars. Not sure where your guy is pricing your compressor but it seems a bit high. Obviously he will have some mark up and maybe he is acquiring through the manufacturer which could really drive the price up.

 

[bobbyp]

Thanks.
Start capacitor was changed with a similar unit and tech determined it was a shorted compressor.
With my limited knowledge of AC, does the compressor just bolt in? He is sourcing the compressor direct from Dometic and seems like an $800 solution would be the way to go.

Here are the capacitors.

Original:

New:

 

[Short Story Long]

From your pics one is 440 VAC the other is 220 vac
Maybe wrong Capacitor Replaced ?

 

[STB]

More curiously 35uF vs 88-107uF? Also the "original" is only ~2 years old?

 

[bobbyp]

Might have to ditch this AC tech.

I no longer have the old cap but it sure looks like Nov 2018 but might be a smudge. I didn't have snything done on the AC from Nov 2018 until this past week.
Had it recharged in NY 3 or 4 years ago but don't recall anything being replaced and I was on the boat with that tech so I'd probably remember.

 

[Duvie]

Sounds like the tech did ok. The voltage on the cap does not matter as long as it is rated above the line voltage. The replacement cap has a higher capacitance rating which probably would be ok also. With caps as long as it is somewhat near the rating and the voltage rating is above the line voltage your good to go especially just to prove things out. Sometimes you improvise with what you have on the truck.

On some units the compressor will bolt up to the service valves but I would bet on the size of your unit the piping is brazed. Also it is not really a DIY project if you do not have the proper tools. The system needs to be leak checked and evacuated after the new compressor is installed and you should have gauges and a proper way to measure the charge going into the system.

Take a look at the information on your current compressor and see if you can find the exact number on the internet and see what you can get the unit for. Some companies have a particular OEM configuration for their parts and you can't find an exact replacement except from the manufacturer. Other configurations may work but may require addition installation work.

You can ask your tech if he can source the part from a non Dometech? source.

 

[gulfstar1]

A grounded compressor will trip a breaker as soon as power is applied. This sounds like what you are describing. There are other things that can trip a breaker as well.
In your pictures you show a run capacitor as the original and a start capacitor as the second or test capacitor. They are similar but not interchangeable. The best test for a grounded compressor is to use a multimeter and check for continuity between each of the compressor terminals and ground. If the tech did this then it sounds like an accurate diagnosis.
I agree that $3000 is high for a standard 2.5 ton compressor. I say that not knowing what compressor is there, The $800 mentioned above is more realistic.
If you have any doubts about what the tech is saying have a reputable company check it at your next stop.

 

[truant2]

Just a side note. I throw a hot tub bromine tablet in my strainers every other month and that seems to keep them cleaner.

 

[Chuck16]

From your pics one is 440 VAC the other is 220 vac
Maybe wrong Capacitor Replaced ?

The voltage listed on the side is the "working voltage". That is the maximum voltage that the capacitor is able to withstand/use without a failure. For the same capacitance (uF) typically the higher working voltage unit will be somewhat larger physically. It does not matter the working voltage rating as long as it exceeds your planned usage. Typically, I like to exceed the circuit working voltage by 50% minimum. So, a 120vac circuit would use a capacitor with 180vac minimum working voltage.

You should meet or exceed the design capacitance in a start up circuit with the replacement. In other applications such as timing circuits, the capacitance would have to be the same.

just an FYI for all you budding engineers out there.

 

[bobbyp]

Looks like I'm going for a new AC unit as this unit is 17 years old and appears to be done with.

Right now waiting out the winds in Fort Lauderdale but the Ocean Breeze people make a direct replacement which they'll install for a reasonable price next time I'm through Stuart in a few weeks.