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Any Heating/AC guys here? I have a question!

Discussion in 'The Garage' started by bigblock454, Oct 17, 2002.

  1. bigblock454

    bigblock454 Clack Clack Clack Premium Member

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    I just received a fully functional 3 Ton AC unit from a friend that installed a totally new system. I have the compressor, air handler and evaporator. My question is on recharging, how do I do it? I have a set of R12 gauges and a Vacuum unit, also got through a friend. My current plan is to pull a vacuum on the system to about 28" and install Envirosafe 22a to the low side. But, how much do i put in? Since I have no documentation on the unit what pressure on the low side is enough? How much refrigerant should I buy?
     
  2. bigblock454

    bigblock454 Clack Clack Clack Premium Member

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    Oh yea, forgot to mention how it applies. This is going in my Garage.
     
  3. 87GMCJimmy

    87GMCJimmy 1/2 ton status

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    Sounds like you have the basics down. There should be a tag somewhere on the system that lists the charge amount in pounds. If not get the model# and such I can call a friend that owns an A/C shop and see if he has a suggestion. Also, an old-timer way to tell if you have enough freon in it is while it's running put your hand on the output on the evaporator as your filling it with freon. As soon as the exit starts to cool off you've got enough.
    Hope this helps.

    Mike
     
  4. 4x4Freak

    4x4Freak 1/2 ton status

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    The ideal lowside pressure should be about 70 psi. Between 60 and 75 is acceptable though. Usually below 60 the system will ice up because the indoor coil becomes too cold. It's best to charge it on a warm day so that the pressures will be more accurate as the freon is pretty sensitive to temperature. A system like that will probably hold around 8 pounds.

    I've worked with my dad doing AC work for a few years and I've never heard of 22a refrigerant. Is this something new? And your also supposed to have a license to purchase most freon. You can recieve a pretty big fine if youre supposed to and get caught.

    I would also advise that you put some filter dryers on the lines to the condensing unit. Another good idea would be to make sure the indoor coil is clean and doesnt have lint and other junk on it. If it is dirty it can cause it to ice up because there isnt enough airflow to keep the pressures up.

    If you have any other questions just send me a PM.
     
  5. 4x4Freak

    4x4Freak 1/2 ton status

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    </font><blockquote><font class="small">In reply to:</font><hr />
    As soon as the exit starts to cool off you've got enough.


    [/ QUOTE ]

    The suction line (big one) should get cold and the discharge (small one) should be warm.

    And yes, there should be a tag that tells the factory charge, if it's not too faded to read. Of course, this will change slightly depending on the length of the lines.
     

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