Air Conditioner Mystery

[combo52]

Corroded Aluminum Condenser Fins

Something got on this one A/C to make it corrode so much faster than the other units.

 

That said this type of aluminum fin coil construction has always been subject to this type of failure and it is nothing new to appliance repair people. Bobby in Va. even said this happened to his 1949 Mitchell A/C, LOL Hopefully he had the extended warranty.

 

The problem today is that the aluminum fins are VERY thin and spaced VERY close together so a Hi-Efficiency unit can be built cheaply and in a small light package.

 

Hi  Efficiency A/C units have been around since the introduction of window type units, but with older construction standards to build a HE unit it would get very large and bulky and heavy [ We have a 1937 Frigidaire one ton=12,000 BTU  room A/C with an EER of over 10  that would easily qualify for an E Star award, but it weighs over 400 pounds and is larger than a DW.

 

The main problem with these newer A/Cs with the closely spaced thin fins is they clog very quickly and the A/C loses efficiency and cooling capacity so frequent cleaning is a must unless it is operated in a very clean environment.

 

Unfortunately window A/Cs have joined microwave ovens, dehumidifiers as throw-away appliances that will seldom be worth any significant repair attempts.

 

John L

 

[whirlcool]

Th fins on our condenser unit outside don't even look like fins, they look like confetti glued to aluminum tubes.

 

[philr]

John L.

Don't forget to say that your 1937 A/C is water cooled, that also helps it to get a higher effiency! It seems true (for some older models at least) that less BTU in the same size box often r helps getting better effiency. I guess the exceptions are the smaller models with not enough tubes in their evaporators/condensers.

I'm wondering why water cooling isn't used anymore on small A/C systems. Wouldn't it be great if a room air conditioner or a heat pump could use the water from a swimming pool to cool it's condenser while it cools the air in your home at the same time. I know a few persons that have heat pump style pool heaters that throw their cool air outside and at the same time have other A/C systems for their house. That would be great for portable units too that could run two small hoses instead of those large tubes that have to be connected to a window.

 

[dj-gabriele]

You can have plenty of water cooled systems over here, however they're not popular on the small scale because of the expense of the cooling water if one doesn't have a closed loop system or some other kind of "discharge" for the waste heat.
(http://www.argoclima.com/mktg/argo_xfetto_2013_en_w.pdf see page 3)

On the other hand there are a few hi-quality companies like ArgoClima (That also make the previous system, with production lines still here in Italy!) that make systems that use the waste heat of summer refrigeration to heat water for domestic use in a totally free manner, plus other amenities like real wood paneling for the indoor spit units et similia...

http://pro.argoclima.com/en/breakin...-for-air-conditioning-and-domestic-hot-water/

 

[danemodsandy]

Chinese Made?

One of the issues I've noticed with a lot of "Made In China" items is inferior metals. I feel that many manufacturers over there care only about making something that looks right - they don't care if it works right, and they certainly don't care if it continues to work right.

When I was in the housewares biz in the '80s, Chinese manufacture was just starting to become a big deal. We had a lot of problems traceable to inferior-quality aluminum, notably impurities and stress fracturing.

I have to wonder if your fins were some aluminum alloy made of whatever scrap happened to be laying around. The fact that one unit suffered this damage while three did not have such a big problem possibly points to a manufacturing inconsistency, to my way of thinking.

I personally would make sure Sharp got a courteous, detailed letter with some photos.

 

[tomturbomatic]

My sister and brother-law's home in Florida has a ground water heat pump. It pulls ground water from a well on their property over the equivalent of the outdoor coil in the indoor unit, which unfortunately also houses the compressor so it is noisy, but near the garage, and a hose carries the water back out to the back yard where the water sinks into the sandy soil so fast that there is not even a wet place in the lawn. It is not very high quality water so it can't be used to add warm water to the pool, although I guess a heat exchanger could be rigged up with the pool's circulation system, but heat is not needed for the pool except for a couple of months in the spring and fall so it would probably not be worth the effort and cost. The system is economical to operate.

A friend had a big heat pump pool heater installed in his house further down the east coast of Florida and even with all of his money, he only used it for one month and did not switch it on again. Solar probably would have been a cheaper way to go but probably would not have been allowed by the homeowners' assoliation.

 

[estesguy]

Water from the inside evaporator coil is routed out to a tray underneath the condenser coil. The fan has a slinger ring on it to sling the water up onto the coil to not only help evaporate the water, but also increase efficiency of the unit by cooling the coil with the water. It appears salt in the air probably combined with the water to corrode the aluminum fins. The arc pattern of damage created would be the exact same area as the water would be slung up onto the coil. Why this unit has more damage than the others? I can only speculate as that maybe this unit was in an area of the home that picked up more moisture from kitchen cooking or bathroom showers. Just my thoughts, since I don't live near the ocean, I can only speculate as to what may have happened.

 

[bajaespuma]

Thanks to all of you.

Thank you all. Very intelligent and some surprising answers and I've learned a lot. I think I will inspect the fins on my AC units more closely in the future and clean them out more frequently. They are so fine and so close together that it is entirely possible that they trapped some foreign material that catalyzed corrosion. I am going to send a picture of the corrosion to the Sharp company just in case this ends up being a manufacturing defect. What's to lose?

 

[tomturbomatic]

We all want to see the letter you get back.

 

[davey7]

I've had the same problem with an old ac unit. It was clogged with newspaper (old biddy I bought from used newspaper to weatherstrip around the unit) and the fins corroded a bit, as well as causing rust in the supports. And I'm nowhere near salt water...