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ac lines freezing

my a/c lines are freezing up and its out. luckly i have dual ac system, what is the reason that its freezing up like that and is it something that i can fix?


  • Ironman
    Ironman Member Posts: 7,076
    Two Basic Causes:

    1. Loss of load on evaporator. Most likely cause: low air flow (dirty filter, dirty coil, blower motor).

    2. Loss of refrigerant feeding evaporator. Most likely cause: system low on refrigerant.

    Do what you can to ensure that you have good air flow. Check your filter, make sure registers are open.

    If your air flow is good, then it's probably #2 above and you need a good tech. Make sure he finds and fixes any leaks if refrigerant has to be added.
    Bob Boan
    You can choose to do what you want, but you cannot choose the consequences.
  • Not all freezing is the same

    When an evaporator coil freezes, there are typically two ice patterns present. One is a partially frozen coil, where only the first few tubes freeze and the rest of the coil is warm. The other is when the entire coil freezes.

    In the first case, there is either an underfeeding metering device or a refrigerant undercharge.

    In the second case, which usually is accompanied by a frozen suction line, is almost always an airflow problem through the evaporator coil.
  • JackLance
    JackLance Member Posts: 2

    One of the main things that causes evaporator line freezing is low gas pressure. If you've cleaned or changed the filters and vacuumed the dust, dirt and debris out of the evap coils (this will be the part indoors with a filter and a fan to blow air over it and through the ductwork) then low gas pressure is a good bet, particularly if the system ran fine.
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