Ac not blowing cold

Discussion in 'Heating & Cooling' started by josephmast94, May 11, 2019.

  1. josephmast94

    josephmast94 Member

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    The air coming out of my main vents and rear vents is not as cold a it use to be. I am hearing what I believe the be the rear txv hissing as the compressor cycles on and off. I just got a set of manifold gauges from O'Riley's loaner tool program, here are my readings.
    Ambient - 70°
    Static system pressure - 84psi equalized
    High side when compressor kicks on - 125psi
    Low side when compressor kicks on - 30psi
    High side when compressor is cycled off - 100psi
    Low side when compressor is cycled off - 50psi

    What is going on? Are those numbers within an acceptable range? Should I try adding refrigerant? I am considering pulling all the refrigerant out, vacuuming, and replacing the correct amount just to see what happens.
     
  2. stamp11127

    stamp11127 Super Moderator Staff Member

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    High side pressure is low according to the chart in the sticky in the Heating / Cooling section. Make sure the condenser is clean and the cooling fan & fan clutch or electric fans are running correctly. Fan shroud should also be in place.
    If you can recover and recharge the system that will make things easier to diagnose - that way you are starting within specification.
     
  3. johnboneske

    johnboneske Full Access Members

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    Its all about outside temp to when charging don't forget. 30 psi low side if I remember correctly is proper charge at 60°. If it is hissing in the rear, it has a low charge. Probably will need 1 to 2 pounds to it right.
     
  4. johnboneske

    johnboneske Full Access Members

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    Here is the chart...

    Temp-pressure-chart-33776F1.jpg
     
  5. 1955moose

    1955moose Full Access Members

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    Yeah, looks like your low but not much. Probably popping in about 10-12 ounces should bring your numbers up. I buy mine in small 12 oz cans. Be sure to wear safety glasses, and wrap a rag around can of freon as you shake it and add it to system low side. Cans get mighty cold!. You might want to have a shop do a beeper test after to see if you have any small leaks. Hopefully it's not the rear. Their harder to get at, but are usually your trouble spot.

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  6. stamp11127

    stamp11127 Super Moderator Staff Member

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    Poof and another one in the wind?
     
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  7. GAIN-MOB

    GAIN-MOB Super Moderator Staff Member Supporting Member

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    Yulp... got his answer and gone with no feedback

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  8. 1955moose

    1955moose Full Access Members

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    They seem to do that a lot around here. I think what it is, is the other websites are so dead, it takes a week or more, just to have a post answered. We're like the old Domino's Pizza delivery, 30 minutes or less!

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