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  1. #1
    Join Date
    Mar 2013
    Location
    DeLand, Florida
    Posts
    13

    Capacity control 06D Carrier used in a/c, factory setting

    Hello,

    We have 20 06D's (6 cylinders, 15 ton) used in a factory. Some have unloaders (no hot gas or electric) installed some don't... 30 years of see what works and not knowing what should be put in (I'm the new guy)!! This is an old factory, lots of outside air coming and going... (Florida!!) we run 5, 10 hour days. Units set at 73* fans run 24/7. Units are keeping the building cool. I can't see the need for unloading, am I not looking at this right? The factory floor is a big open area.

    I think I have a few capacity control problems. I would like to remove the unloaders, leaving me with fully loaded units. ?

  2. #2
    Join Date
    Jul 2011
    Location
    East coast USA
    Posts
    955
    whats the problem?

  3. #3
    Join Date
    Jan 2008
    Location
    In the work truck
    Posts
    2,990
    Why would you want to remove them? IF they are not leaking I think you could come up with something better to do with your time then playing with that.
    Gotta have the right tool for the job!

    Where is all the stuff MADE IN THE USA?

    "Thats what we do Troy. Incredible, Invisible, Imbelivable things. We are an Unseen, Unknown, Unvincible fraternity of craftsman.."

  4. #4
    Join Date
    May 2000
    Location
    Salem, WI US
    Posts
    61
    The Unloaders are designed to unload the compressors to maintain a desirable suction pressure, if you remove them you could create a liquid flood back situation while operating under low low load conditions that will very easily destroy the internal components of the compressors.
    Betabass



    Success is to be measured not so much by the position that one has reached in life as by the obstacles which he has overcome.

  5. #5
    Join Date
    Mar 2013
    Location
    DeLand, Florida
    Posts
    13
    We never have low load conditions, my pressures are all over the place and both the TXV's and Capacity Control's are not setup right. I just walked in on this setup.... Fun Fun Fun..

    I have two units that I can "play with", I did find some good spec's to start with. When I started here 2 units had burnt up and left with the compressor control wiring pulled, but the cond. fans running as if unit was working....! With 58 units total, half do not have the unloaders working/setup right and do not have unloaders installed.

    I just wanted some feed back on unloaders in general.

  6. #6
    Join Date
    Mar 2013
    Location
    DeLand, Florida
    Posts
    13
    Found some of the problems...

    ""Some 06D's are supplied with one plugged hot gas bypass unloader head or one blocked suction cutoff head and will operate fully loaded.""

    Someone in the past installed the Capacity Control not using the supplied piston (hot gas head), they left the old plug in!!!

    Found some with no unloader heads at all.

  7. #7
    Join Date
    May 2009
    Location
    Bardstown, KY
    Posts
    94

  8. #8
    Join Date
    Mar 2011
    Location
    North Carolina Piedmont Area
    Posts
    448
    Do you need help on how to set up the unloaders?
    But I am still learning and looking for a new mentor.
    _______________________
    In a strict sense troubleshooting is not part of the repair..........understand the symptoms and you will find a solution.

  9. #9
    Join Date
    Mar 2013
    Location
    DeLand, Florida
    Posts
    13
    Thanks for the reply. Got the unloaders setup right.... They were all over the place!! That helped get the TXV's set right (superheat). I did find some heads with unloaders (hotgas) that I will install on the units without unloaders. I think someone in the past changed them out!?? I'm going from one unit at a time now. Did find lots of rebuilt 0D6 replacement paper work, alot of burnouts in the past.

    Lots of smiles from the floor now.... 72* was in the upper 70's*.

  10. #10
    Join Date
    Mar 2011
    Location
    North Carolina Piedmont Area
    Posts
    448
    How many steps of unloading do you have on each 06D compressor.
    What pressures have you set the unloaders to load and unload the compressors?
    What evaporator saturation temperature are you trying to maintain?
    Do you have a single evaporator or multiple evaporators per circuit?

  11. #11
    Join Date
    Mar 2013
    Location
    DeLand, Florida
    Posts
    13
    Alcomech,

    Just one step of unloading, some are hot gas others are suction. I do have a few with no unloading (changing this). The setting I'm using is from the service manual; 70* 60*. I'm going for a superheat of 20* (service port suction side). Some have two coils (in one AHU) with two 06D's, one compressor one coil, one compressor two coils (two TXV's) no solenoid cut out, two compressors two AHU's (one coil) with solenoid cutouts. Some of these are from the 1980's...

    Sounds fun, does't it...

  12. #12
    Join Date
    Nov 2003
    Location
    Montreal, Qc.
    Posts
    775
    I ran into this a week ago.
    The hot gas unloaders need to have the lower piston installed on the unloader.
    The suction cutoff unloaders do not need the piston.
    When a hot gas head is able to accept an unloader but one is not present there is a plug in the head that must be removed below the blank off plate.

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