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  1. #1
    Join Date
    Jul 2016
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    Hot Gas bypass or EDC

    Should I install a hot gas bypass in this system I'm installing or go with Trane's recommended EDC kit. I don't think its going to work well anyway based on the 150 feet of equivalent length of 5/8 . Trane recommends the evaparator defrost control kit over HGB for a number of following reasons: energy costs, initial cost, extra refrigerant charge, more joints that could leak and overall system reliability. EDC would simply shut the compressor off on event of frost and start back up when coil warms up. Seems better but would like your feedback based on your experiences. System info, Outdoor unit is a TTA180H micro channel condenser. dual circuit 7.5 tos per circuit. Air handler has matched split coil with fresh air economizing etc. Thanks

  2. #2
    Join Date
    Apr 2003
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    I don't think that hot gas would work without a added receiver tank because of the very little refrigent capacity of the micro channel coil.Not enough capacity to run hot gas and liquid at the same time. Charge at full hot gas, charge at 95*.

  3. #3
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    Jun 2016
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    If Trane is recommending it on their equipment, why would you doubt it?? Go with their recommended item

    Sent from my SM-G920V using Tapatalk
    We can control fire & ice.....

  4. #4
    Join Date
    Dec 2004
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    Chicago area
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    So long as there kit will shut the unit down before so stupid lockout, then I would do that.

    Is this a VAV system?


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  5. #5
    Join Date
    Jul 2016
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    Thread Starter
    Yes it is a VAV system.
    Regarding the condensing unit, the spec shows a TTA180 E but we were shipped the H units. the difference being non micro-channel and micro channel respectively. I don't know much about the EDC kit but Trane recommends it as apposed to HGBP. I guess it would have a threshold above lockout hopefully.

  6. #6
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    Jun 2016
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    Those damned micro channel units are becoming a pain in the butt. Haven't had much of an issue with Trane's equipment, but a LOT of companies are suggesting removing a pound of refrigerant if they immediately pop hp on startup. If it continues they suggest a compensator kit. Wave of the future they said... reminds me of the tsunami waves in Thailand and Japan's Fukushima nuke plant.
    ,

    Sent from my SM-G920V using Tapatalk
    We can control fire & ice.....

  7. #7
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    Jul 2016
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    Thread Starter
    I've had to remove Gas out of Lennox rtu's due to that reason.

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  9. #8
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    Jun 2016
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    Plano, TX
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    Yes that's what we recommend. 1/2 to 1lb.

    Sent from my SM-G920V using Tapatalk
    We can control fire & ice.....

  10. #9
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    Jul 2016
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    EDC Kit appears to be the only safe bet for this system application ( VAV ) Hot gas bypass for this system would present possible oil return issues due to the long line set and head pressure safety trips at start up due to the excessive refrigerant charge with the MCHX coils utilized with this condensing unit. A condensing unit with capacity control ( Digital Scroll Feature) ( VFD on the condenser fan during low ambient ) to match system capacity during low load conditions would have been ideal during the system selection stage.

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  12. #10
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    Jul 2016
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    Thread Starter
    Thanks for your input fla, hedrash and heatingman. From what I've learned there is many of these jobs require design refinement consultation and consideration of other options before installation which would result in change orders and delays. They throw me on site and tell me to rush it because other jobs are waiting. Next time I will assume that the application needs design refinement based on real world limitations or selection errors and I will not start until I've checked those details. Even if it means bringing the engineers on site.

  13. #11
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    Jul 2000
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    All this tells me is Trane is OK selling equipment for a VAV system which isn't compatible with VAV. Who spec's this anyway?

    You need unloading capability, not something to shut it down when it freezes up...ie,digital scroll, variable speed, HGBP, etc

  14. Likes ruuufuhbock liked this post
  15. #12
    Join Date
    Jun 2016
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    If you're working on a particular make of system, the manufacturer has teams of parts experts, inside technical support, applications, etc. Go to them, they'll have revisions and technical data not necessarily available to the general public. If they say use something, do such. Trust me I work for a large manufacturer in their inside Tech support department. There's a lot of common problems we come across & have quick fixes for. If not there's the applications department will basically get you anything you need.

    Sent from my SM-G920V using Tapatalk
    We can control fire & ice.....

  16. #13
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    Aug 2006
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    Mixing oil and fire with a big spoon.
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    i prefer HGBP. i like it a lot. with that being said, it can be very difficult to size things properly for operation and oil return. There are many variables to be concerned with. Trane likes to sell equipment. cycling the crap out of compressors is not their problem, however, compressor warranties are.
    Don't step on my favorite part of the Constitution just to point out your favorite part.

    Political Correctness is forced on you because you have forgotten decency.

    Technically speaking, they are all heat pumps.

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