Ac pressure goes up and down what's wrong

Discussion in 'Engine & Drivetrain' started by ladorn45, Jun 9, 2018.

  1. ladorn45

    ladorn45 Full Access Member

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    Hey everyone was charging my ac with the AC pro charging kit. When I hook the kit to the low pressure vaulve the pressure goes to 50 then the I hear I noise (think the compressor kicks on or off) and the pressure drops to 20. It cycles like this the whole time. Anyone know what's going on
     
  2. Scottydoggs

    Scottydoggs Full Access Member

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    pretty sure it will cycle like that till it reads full. if your going from dead empty.
     
  3. ladorn45

    ladorn45 Full Access Member

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    So should i keep filling it up. Im just nervous to keep filling it since 50 is the max point on the ac charge pro guage
     
  4. Scottydoggs

    Scottydoggs Full Access Member

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    as long as it drops back down to the green range on them gauge on the can.

    ive been lucky as hell, have not had to mess with any thing ac related for years now.
     
  5. Randy Whistler

    Randy Whistler Only visiting this planet Supporting Member

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    Scotty's right. The compressor will cycle on/off in normal operation, with the exception of when you have the A/C set to MAX. In normal operation, the compressor will cycle when necessary to condense the Freon coolant. In MAX operation, the compressor will run continuously.

    The readings you're seeing are correct as well, to a point. As Scotty said, as long as your readings stay within the "acceptable" range on your gauges, you should be fine. It will take some practice to feel fully comfortable with the recharge process, but the simplest way to get used to is is what you're doing. Just charge it slowly, watching your gauges, and take your time.

    One other thing, too: your Freon can will chill quickly on the bottom when filling. You'll need to swirl the can around to keep it from freeze-locking, but do not use heat!
     
  6. 01ssreda4

    01ssreda4 Full Access Member

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    Normal with a low charge. Keep filling.

    Another thing, during non-use, pressures are the same. There is no high or low side. They settle in around 80 psi. When the compressor runs its sucks one side lower and pressurizes the other higher. When your low side spikes its going back to resting pressure due to the compressor not running. Fill with AC running on high.
     
  7. ladorn45

    ladorn45 Full Access Member

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    Thanks everyone
     

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