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  1. #1
    Join Date
    Oct 2005
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    BC
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    Micro Channel Condenser and High Head

    Just completed a warranty compressor change out on a York Sunline 3 ton RTU. After weighing in factory charge and running the unit in cooling to verify proper operation we found the head pressure fairly quickly (less than 2 mins) elevating to above 500 psi and trip out on high head. I was testing in a relatively low ambient (approx 40F). Coil is clear, OFM running in the right direction.

    After consulting with the local York rep, he figures this is due to a lack of internal area in the condenser for a surplus of liquid refrigerant to stack up, as is possible with a traditional tube style condenser. He said he`s encountered this with the Micro Channel coils and low load/low ambient in the past.

    Does this explanation sound legit? Anyone else encountered this?

  2. #2
    Join Date
    Apr 2007
    Location
    Saint Augustine, Florida, United States
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    1,169
    Don't know what your metering device is , but sounds restricted. Local guys whose co. uses York hate those coils. Just what they whine about at the supply house. What did the suction side do?

  3. #3
    Join Date
    Jan 2008
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    Dallas ,Texas
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    Sounds about right to me.
    UA 100

    It takes three people to do anything around here. Two do the work, one explains to the crowd of people who showed up when they seen smoke and flames.

  4. #4
    Join Date
    Aug 2010
    Location
    Little town in Texas
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    337

    ...

    I wanted to post here so I can follow this thread. I have had evap. Coils slugged with oil do this. And like the other guy said,what did the suction do? What metering device u using?
    "If you can’t describe what you are doing as a process, you don’t know what you are doing." ~ W. Edwards Deming

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  5. #5
    Join Date
    Oct 2005
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    BC
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    The unit has a txv and suction pressure was around 120 psig.

  6. #6
    Join Date
    Jan 2008
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    Dallas ,Texas
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    3,725
    Quote Originally Posted by refer madness View Post
    The unit has a txv and suction pressure was around 120 psig.
    As far as the discharge line piping goes is there a "trap" in between the compressor and the inlet of the condenser? Is it a hard shut off TXV or does it bleed somewhat?
    UA 100

    It takes three people to do anything around here. Two do the work, one explains to the crowd of people who showed up when they seen smoke and flames.

  7. #7
    Join Date
    Feb 2010
    Location
    MEXICO
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    475
    is r-22? r 410-a?

  8. #8
    Join Date
    Dec 2005
    Posts
    1,923
    Quote Originally Posted by refer madness View Post
    Just completed a warranty compressor change out on a York Sunline 3 ton RTU. After weighing in factory charge and running the unit in cooling to verify proper operation we found the head pressure fairly quickly (less than 2 mins) elevating to above 500 psi and trip out on high head. I was testing in a relatively low ambient (approx 40F). Coil is clear, OFM running in the right direction.

    After consulting with the local York rep, he figures this is due to a lack of internal area in the condenser for a surplus of liquid refrigerant to stack up, as is possible with a traditional tube style condenser. He said he`s encountered this with the Micro Channel coils and low load/low ambient in the past.

    Does this explanation sound legit? Anyone else encountered this?
    From the number, my guess is 410A freon.

    I think the York rep's explaination is BS.
    I think the scale you used was probably inaccurated. Please read the total charge and weight it in again with a different scale. It does not take much to over cahrge this micro-channel condenser coil system.

  9. #9
    Join Date
    Jan 2010
    Posts
    6,826
    On checking your charge.
    Is there any fan cycling with that unit ?
    120 psi looks like 41*

    What's next coil heaters ?

  10. #10
    Join Date
    Mar 2003
    Posts
    7,326
    I have been on the phone with factory guys and can tell you some things they have told me. Example: hey factory guy, your nameplate charge isnt right." Well, yeah, we havent quite gotten these new refrigerants down yet, we were pretty good with r22, but still experimenting with r410. set it up for eight to ten subcooling, and fifteen superheat, and go from there......."

    Look at actuall conditions and charge accordingly. if no restriction, take some juice out lad.

  11. #11
    Join Date
    Oct 2005
    Location
    BC
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    32
    I think you guys are right about this being an overcharge. I'll be back at site tomorrow morning and will adjust the charge as needed. Really appreciate all the quick feedback.

    To answer a couple of other questions:

    * Not sure whether the TXV is hard shut off or bleed type, but will try to find out.
    * No fan cycling installed
    * This is indeed R-410A

  12. #12
    Join Date
    Jan 2008
    Location
    Dallas ,Texas
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    Quote Originally Posted by refer madness View Post
    I think you guys are right about this being an overcharge. I'll be back at site tomorrow morning and will adjust the charge as needed. Really appreciate all the quick feedback.

    To answer a couple of other questions:

    * Not sure whether the TXV is hard shut off or bleed type, but will try to find out.
    * No fan cycling installed
    * This is indeed R-410A
    Take 1% of the charge out and see what happens. 410a is a weird animal.
    UA 100

    It takes three people to do anything around here. Two do the work, one explains to the crowd of people who showed up when they seen smoke and flames.

  13. #13
    Join Date
    Jun 2009
    Location
    Bakersfield, Ca
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    1,716
    Quote Originally Posted by refer madness View Post
    I think you guys are right about this being an overcharge. I'll be back at site tomorrow morning and will adjust the charge as needed. Really appreciate all the quick feedback.

    To answer a couple of other questions:

    * Not sure whether the TXV is hard shut off or bleed type, but will try to find out.
    * No fan cycling installed
    * This is indeed R-410A
    I think you're on the right track. I've seen this on a microchannel York 5t with a partially clogged strainer as well. You should be able to pump it all down as it is nameplate. If you can't you know they gave wrong data. If you can, check the txv strainer as well.

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