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  1. #1
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    Using compressor as a vacuum pump to pull vacuums



    Hi recently an apprentice I was working with used the compressor to pull the unit into a vacuum. He closed off the discharge service valve, removed the cap tube off it, cracked open the suction valve and connected his suction gauge on, he then ran the compressor and it pulled into a vacuum, once he finished doing that, always in a hurry he then forgot about the discharge side being closed, put the cap tube back on and charged unit with 60psi of liquid R404a and then tried to run it Very strange noises occurred after that, the compressor makes a half hearted effort to start, almost like it doesnt have enough power to run it, and then it trips the CB and is quite warm on the outer casing. Please Help



  2. #2
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    Re: Using compressor as a vacuum pump to pull vacuums

    Buy a new compressor!

  3. #3
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    Re: Using compressor as a vacuum pump to pull vacuums

    Based on what you have said and assuming all the service valves are in the correct position for running, it sounds like the compressor is siezed, would have been cheaper to use a proper vacuum pump even if in meant buying one....

    Of course its possible its not wired up properly also.

  4. #4
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    Re: Using compressor as a vacuum pump to pull vacuums

    Quote Originally Posted by mad fridgie View Post
    Buy a new compressor!
    If my boss does, he's probably gonna buy another apprentice too and throw the old one out with the old compressor. I was told that too much liquid probably would have caused the compression of liquid in the shaft causing a locked rotor, causing the unit to trip, he suggested i reclaim all the 404 and leave valves open for a couple of hours, would that work

  5. #5
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    Re: Using compressor as a vacuum pump to pull vacuums

    Quote Originally Posted by mad fridgie View Post
    Buy a new compressor!
    and a vac pump......

  6. #6
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    Re: Using compressor as a vacuum pump to pull vacuums

    Quote Originally Posted by monkey spanners View Post
    Based on what you have said and assuming all the service valves are in the correct position for running, it sounds like the compressor is siezed, would have been cheaper to use a proper vacuum pump even if in meant buying one....

    Of course its possible its not wired up properly also.
    service valves are in running position and condenser unit came fully prepared from the factory, so compressor wiring is correct. It runs but for like 2 seconds and then makes a slight knocking sound and then trips

  7. #7
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    Re: Using compressor as a vacuum pump to pull vacuums

    Quote Originally Posted by monkey spanners View Post
    and a vac pump......
    I agree but the boss dont, he believes they a waste of time and money, he just tells us to purge the system.

  8. #8
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    Re: Using compressor as a vacuum pump to pull vacuums

    Quote Originally Posted by tudorice View Post
    If my boss does, he's probably gonna buy another apprentice too and throw the old one out with the old compressor. I was told that too much liquid probably would have caused the compression of liquid in the shaft causing a locked rotor, causing the unit to trip, he suggested i reclaim all the 404 and leave valves open for a couple of hours, would that work
    OK, if you are lucky, and it was completely full of liquid, there maybe a chance that no rotation occured, you simply overloaded the motor. So open up your valves, heat the crankcase (this will boil off any liquid, no point F****** any futher) Do not reclaim yet. When warm, restart! If it work great (as far as reclaiming yes this should be done, vacuum with a vac pump, recharge with NEW refrigerant, destroy old refrigerant), if not "well".
    The apprentice not his fault, he is the apprentice, and unfortunatly this is part of the learning curve, you show me some one who has not f*** up in this industry, I will show you a liar!!!!

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