Air conditioner question

Discussion in 'Heavy Duty Diesel Truck Mechanics Forum' started by Perchie15, Jun 4, 2025.

  1. Perchie15

    Perchie15 Light Load Member

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    I have a 2014 westernstar dd15 and it forsure leaks freon but I use shop air (yes I know we’re not supposed to) but I use it and the gauges haven’t dropped pressure in an hour! So can it be a leak when it only runs? The compressor and everything I thought it’ll leak either way cause it’s under pressure.
     
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  3. Big Road Skateboard

    Big Road Skateboard Road Train Member

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    High side pressure can get up to 325-350. How much pressure you got? Not enough
     
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  4. Perchie15

    Perchie15 Light Load Member

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    125psi it’s the highest it’s letting me go! Then how the heck can I get it higher with shop air?
     
  5. Big Road Skateboard

    Big Road Skateboard Road Train Member

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    You can adjust your pressure switch to a higher pressure.

    That's why we always used Nitrogen with a regulator. No moisture, high pressure
     
  6. Lazer

    Lazer Road Train Member

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    I’m lost here. How does the shop air compressor have anything to do with leaking Freon?
     
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  7. Big Road Skateboard

    Big Road Skateboard Road Train Member

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    He's using shop air pressure to try to find his leak, but they're usually cut to 115-125 from the factory.

    That's often not enough pressure to find a leak
     
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  8. Lazer

    Lazer Road Train Member

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    I have never heard of anyone pressurizing an A/C system with an air compressor, would that raw air contaminate the system?
     
  9. Big Road Skateboard

    Big Road Skateboard Road Train Member

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    Definitely gonna put a bunch of moisture in it. It'll need a new dryer.
     
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  10. wore out

    wore out Numbered Classic

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    Yes shop air will put moisture in the lines. A new drier is a must. In my opinion anytime you have one open it’s best to do a drier and vacuum it. Moisture boils in a vacuum at like 70 degrees that’s the whole purpose of pulling a vacuum.
     
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  11. Perchie15

    Perchie15 Light Load Member

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    On the truck itself how do I go about that? It has the TVC valve or whichever it’s called I don’t see anywhere that’s adjustable
     
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