Why would my window ac unit only drop 10* regardless of outside temp?

It's an old GE window unit, probably from the 70s or 80s, but it blows ice cold and runs like a champ. The problem is, when the inside temp gets to about 10* below the outside temp, it stops. I mean it keeps blowing, but it's like the compressor disengages as if by a thermostat. It only has low-med-hi settings. I always have it on hi. If it is 79* out it will cool the room down to 69*. If it is 102* out it will only cool the room down to 92*. Then the fan just blows. Was this some sort of primitive energy efficiency tactic? Can I get in there and pull some wires or something to override it so the compressor keeps running? I can afford a new unit, but I'd hate to replace this one as it is a perfectly matching component of my restored vintage VW camper. Any thoughts on how I can twist it's arm, so to speak, and keep that compressor engaged would be greatly appreciated.

5 Answers

  • 9 years ago
    Favorite Answer

    There is a small wire-like thermostatic thermocouple that sometimes has a small bulb on the end sits in the incoming air stream at the evaporator. If that bulb touches the coil in any way, it will prematurely shut off the compressor, making the thermostat think its cool enough....

    Source(s): a/c tech
  • Marko
    Lv 6
    9 years ago

    Yes, the oldies crank out the cold using the R-22 refrigerant. I still have two of them. The new R-410a's aren't as cold.

    A compressor can stop running when the thermostat setting is reached and the contacts open or it's overload safety opens to protect the compressor if it overheats. It can overheat when the condenser part in the back is dirty which is what it very well could be after 30 years.

    I'd remove it and put it on the back of a pickup and wash it out. Cover the electrical section with foil or plastic after you slide it out of the casing.

    They don't make them like that anymore so it may be something you want to do to keep it running.


    I could be the bi-metal thermostat. It's located on the evaporator, in the front, in the return air stream. It may be dirty, too, but you have to be careful cleaning it.

  • 9 years ago

    The only thing I can think of is to turn the temperature knob way up, to a setting of 9 or 10.

  • Anonymous
    9 years ago

    New units are very inexpensive now and a lot more energy efficient than your old unit. Having any pro work on it will cost more than replacing.

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  • korff
    Lv 4
    3 years ago

    confirm you install horizontally and rear tilted 10 mm downward so as that water may be drained thro. the hollow. interior the humid section you would be able to could desire to place in a basin with drain pipe under the ac. if your way of venting air reasons low overall performance, you would be able to could desire to place in an exhaust fan on the tip of the outdoors vent to strengthen the cooling of ac.

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