New AC Unit Frosting over... plz help!


  #1  
Old 07-21-12, 06:40 PM
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New AC Unit Frosting over... plz help!

My new AC unit in my window in my bedroom was working great for the first few months. Now, however, it literally builds-up so much frost on the front under filter that it completely blocks airflow into the AC unit. When I remove the front plastic shield and the filter beneath it, I can see a thick layer of frost and ice. I can wait 2-3 hours for it all to melt away if I turn the AC unit off for a while, but when I turn it back on it just freezes and frosts over again.

Are there any solutions to prevent ice and frost buildup? Could the solution be as simple as spraying it with anti-freeze? Please provide some instructions... maintaining this AC unit by letting the ice and frost melt everyday is very annoying.

Thanks!
 
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Old 07-21-12, 07:04 PM
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There are three main reasons why the evaporator (cooling) coil freezes up.

1. Insufficient air flow through the coil. Generally caused by a dirty filter, dirty coil or dirty fan. Sometimes caused by high humidity and too slow a fan speed.

2. Thermostat controlling the compressor (window units) has been removed from the evaporator coil keeping the compressor from cycling off when coil temperature drops close to 32 degrees F.

3. Low refrigerant charge.

The first and second reasons you can check. The refrigerant charge you cannot check. Unless the unit was defective from the box you have most likely, albeit unwittingly, somehow caused a leak in the refrigeration system. Assuming it is still under warranty take it back where you bought it and request either a new unit, a refund or an adjustment.
 
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Old 07-23-12, 04:11 PM
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Thumbs up Solution

Thanks for the reply! I actually figured it out the night I posted my original question. I had checked the filter previously but due to poor lighting conditions, didn't notice a very thin layer of dust. I'm truly astonished by how much of a difference such a small amount of dust can make! I cleaned the filter, and just for safe measure increased the temperature setting from 61 deg C to 65 deg C (thereby reducing the delta T). It has been working flawlessly ever since. I strongly suspect the only cause of the problem was the thin layer of dust. The filter itself is so thin, it's hard to believe it really does much at all, but the evidence speaks for itself.

Thanks again for the reply! And remember folks, when it doubt, clean your filters!
 
 

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