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  1. #1
    Join Date
    Sep 2011
    Posts
    7

    Vacuuming Refrigerator System (Triple Evacuation)

    Hello,

    I was vacuuming the residential refrigerator system with 3CFM pump that I've got from Harbor Freight Tools using Supco Vacuum VG64 gauge. Pump was brand new attached through copper hose to suction line, vacuum gauge was connected using one of the gauge manifold flex hoses to high side line. Vacuum gauge stops at 1100 microns and never goes below. After 30-40 minutes it even starts going up to 1200 microns (probably because pump is getting hot and inefficient). I tried to blow it through with dry nitrogen and to do all over again but no results. I purchased new Battery for vacuum gauge but still nothing gets better. I was wondering if I do something wrong or it's bad vacuum gauge?
    Please help!
    Thank you!

  2. #2
    Join Date
    Jan 2004
    Location
    Lancaster PA
    Posts
    68,174
    Test the pump.
    Contractor locator map

    How-to-apply-for-Professional

    How many times must one fix something before it is fixed?

  3. #3
    Join Date
    Sep 2011
    Posts
    7
    I actually purchased second pump and was running it with the oil added. When I was pressurizing the system and valving it off for 10-15 min no drop was indicated on the vacuum gauge. Seems like there is no leak.

  4. #4
    Join Date
    Jul 2006
    Location
    Northern Colorado
    Posts
    442
    Clean the sensor on the vg64. Do so frequently.
    Hvac Maniac

    "A negative attitude cancels out positive skills."

  5. #5
    Join Date
    Dec 2005
    Location
    Cincinnati, Oh
    Posts
    5,054
    might have something to do with the pump.
    "Better tell the sandman to stay away, because we're gonna be workin on this one all night."

    "Dude, you need more than 2 wires to a condenser to run a 2 stage heatpump."

    "Just get it done son."

    Dad adjusted

  6. #6
    Join Date
    Sep 2011
    Posts
    7
    Do you think after 4-5 uses vacuum gauge could get bad? but it was steadily keeping the same vacuum for 20 mins and then was going up after 30-40 mins. I poured alcohol inside and capped it for 3-4 days now. I hope it will help.

  7. #7
    Join Date
    Sep 2011
    Posts
    7

    TO HVACVEGAS

    What do you mean I need two wires to condenser??? Do you mean hoses?

  8. #8
    Join Date
    Jan 2007
    Location
    Stongsville Oh
    Posts
    902

    Wink Vacuuming refrigerators 101

    I have never vacuumed a refrigerator. My wife usually washes it with mild soapy warm water.
    ckartson
    I didn't write the book I just read it!

  9. #9
    Join Date
    Dec 2005
    Location
    Cincinnati, Oh
    Posts
    5,054
    Quote Originally Posted by rishat View Post
    What do you mean I need two wires to condenser??? Do you mean hoses?
    That part of the post is not related to your post in anyway. It is my signature, and are things that I say, quite often unfortunetly.


    Your micron gauge can become "dirty" after 5 minutes of use.
    During your evac, if your micron gauge is not well above the vacuum pump (like micron gauge on top of the condenser, pump on the ground), then you can pump vacuum pump oil into your micron gauge, causing contaimnation.

    It will then read incorrectly.
    "Better tell the sandman to stay away, because we're gonna be workin on this one all night."

    "Dude, you need more than 2 wires to a condenser to run a 2 stage heatpump."

    "Just get it done son."

    Dad adjusted

  10. #10
    Join Date
    Mar 2010
    Location
    Arnold, Mo
    Posts
    437
    It's probably the Harbor Freight vacuum pump!

  11. #11
    Join Date
    Aug 2011
    Location
    Goose Creek ,SC
    Posts
    252
    Quote Originally Posted by flanders View Post
    It's probably the Harbor Freight vacuum pump!
    best news I've heard all day
    "I just think things should work properly"
    Freon is a brand name-word


  12. #12
    Join Date
    Sep 2011
    Location
    Augusta, ME
    Posts
    76
    If i am correct when you do a triple evacuation you pull down to approx 1500 microns then pressurize system with nitrogen to just above 0 psi to like 5 psi and then pull vacuum to 1000 microns, pressurize again, and vacuum down as far as system will go. by the sounds of it you are purging nitrogen allowing air to get back into the system briefly everytime you purge. Is this proper technique?

  13. #13
    Join Date
    Aug 2011
    Location
    Goose Creek ,SC
    Posts
    252
    Quote Originally Posted by sgagne199 View Post
    If i am correct when you do a triple evacuation you pull down to approx 1500 microns then pressurize system with nitrogen to just above 0 psi to like 5 psi and then pull vacuum to 1000 microns, pressurize again, and vacuum down as far as system will go. by the sounds of it you are purging nitrogen allowing air to get back into the system briefly everytime you purge. Is this proper technique?
    there are several pieces of literature available more fully explaining the procedure ,I actually found the info in an a-coil aftermarket kit
    "I just think things should work properly"
    Freon is a brand name-word


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