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  1. #1
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    Carlyle 06EX299 low suction pressure trouble help ?

    A split condensing unit with Carlyle 06EX299 compressor 40HP,36.75 Ton R22.
    AHU has 4 stages, 4 txv sporland pve-11-cp100, 4 LLSV .
    1HGBP unloader.

    first stage has discharge bypass valve for capacity control ADRHE-6. 0/80, 9.58 tons.
    fan cycling maintaining 215 psihead pressure.

    when call for Mech cool all 4 stages LLSV energized, suction pressure normal, 58 to 65 psi with HGBP unloader, return air temp 71F. SH at compressor suction 18F.

    the issue is when its destaging from 4 to 1st stage the suction pressure went below 25 psi and tripped the LPS rated 25-65 PSI. NEW discharge bypass installed, adjustment its at max and still not enough to maintain desire pressure 50 psi at low load condition. when it tripped I can hear the discharge bypass feeding thru.

    during hot day, this unit has no issue, only when outdoor temp around 60 to 70 F this unit will short cyling on LPS.

  2. #2
    Join Date
    Jun 2008
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    Windsor, Ont.
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    Sounds to me like you don't have enough unloading capacity to accommodate a single stage of cooling. Sad to hear it's HGBP unloading, I would think suction cutoff unloading would be more suitable assuming this is air conditioning duty with R22.

    Additionally is your hot gas bypass valve tied in on 1st stage between the TXV and the distributor, if so was it a Sporlan distributor with the internal orifice?? Sporlan has a special Hot gas Tee connection that places the orifice immediately after the TXV and upstream of the hot gas injection port. See page 22 of PDF.

    http://sporlanonline.com/literature/20/20-10.pdf



    I think I would look into unloading 2 of the 3 heads on that compressor (suction cutoff prefarably) if you need that kind of turndown, just make sure your piping will return oil at that low of a load.
    Last edited by nyrb; 05-12-2018 at 04:12 PM.

  3. #3
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    Thread Starter
    Quote Originally Posted by nyrb View Post
    Sounds to me like you don't have enough unloading capacity to accommodate a single stage of cooling. Sad to hear it's HGBP unloading, I would think suction cutoff unloading would be more suitable assuming this is air conditioning duty with R22.

    Additionally is your hot gas bypass valve tied in on 1st stage between the TXV and the distributor, if so was it a Sporlan distributor with the internal orifice?? Sporlan has a special Hot gas Tee connection that places the orifice immediately after the TXV and upstream of the hot gas injection port. See page 22 of PDF.

    http://sporlanonline.com/literature/20/20-10.pdf



    I think I would look into unloading 2 of the 3 heads on that compressor (suction cutoff prefarably) if you need that kind of turndown, just make sure your piping will return oil at that low of a load.
    Yes R-22 refrigerant,
    Hot gas tied to between TXV and distributor, I have to take a closer look if it has internal orifice.
    It has double suction riser and less then 10 ft, so oil return shouldn't be a problem.

    I phone carrier HGBP pressure unloader no longer available, there is conversion kit to SCOU unloader.
    How common is to have 2 SCOU unloader on 06E compressor? I don't think I seen one before.

    Thanks.

  4. #4
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    Jun 2008
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    Not uncommon at all on 6 cylinder compressors but I would change both to suction cutoff if it was me. Need to decide if you want mechanical or solenoid unloader valves as well.
    Did this system work fine before and only now has issues?

  5. #5
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    Thread Starter
    Quote Originally Posted by nyrb View Post
    Sounds to me like you don't have enough unloading capacity to accommodate a single stage of cooling. Sad to hear it's HGBP unloading, I would think suction cutoff unloading would be more suitable assuming this is air conditioning duty with R22.

    Additionally is your hot gas bypass valve tied in on 1st stage between the TXV and the distributor, if so was it a Sporlan distributor with the internal orifice?? Sporlan has a special Hot gas Tee connection that places the orifice immediately after the TXV and upstream of the hot gas injection port. See page 22 of PDF.

    http://sporlanonline.com/literature/20/20-10.pdf



    I think I would look into unloading 2 of the 3 heads on that compressor (suction cutoff prefarably) if you need that kind of turndown, just make sure your piping will return oil at that low of a load.
    Quote Originally Posted by nyrb View Post
    Not uncommon at all on 6 cylinder compressors but I would change both to suction cutoff if it was me. Need to decide if you want mechanical or solenoid unloader valves as well.
    Did this system work fine before and only now has issues?
    It has the same issue last year, prior to that it has no history available according to the building Operator.
    The condensing unit is Trane RAUA-5006-EB I believe is 1984, the compressor had been changed a few time in the past.

    According to our local Trane , they never use Carlyle for their unit.
    Trane original compressor is 2E5*48, 50 Ton,
    4 Cy. Suction pressure unloading.

  6. #6
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    Are the TXV’s all in the same AHU?

    If so, you could link stage 1 and 2 Solenoids together.

    1 evap circuit sounds like its not enough mass flow for the compressor, with only 1 unloader.

    Long term, change the heads and covert to suction cut off unloaders.




    Sent from my iPhone using Tapatalk

  7. #7
    Join Date
    Jan 2017
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    Pennsylvania
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    Sounds like someone hacked this up. Isn't Carlyle a Carrier product? Not sure if Trane would like that much. lol

  8. #8
    Join Date
    Aug 2010
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    Dearborn MI
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    The Carlyle 06E299 is a 40 ton compressor and the Trane 2E48 was a 50 ton. I'm not sure that this system will ever be right. I would be concerned that the the line sizes are wrong and unloading the compressor will trap oil out in the system until it comes back as a slug and fails the compressor. The Trane had 3 steps of unloading and was a much bigger compressor then the Carlyle.

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