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  1. #1
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    Suction pressure temperature chart Goodman unit


    This weekend I just fired up a brand new Goodman system. R-410A refrigiant. The Suction pressure temperature chart in the Condensing Unit installation & service reference that came with the unit only goes up to 80 psig, yet I'm seeing 135 psig at the low side service valve. Looking elwhere I found that 135 psig is 47F. High side 285 psig which is 92F. Spec is SH 7-9F and SC 7-9F (using TXV).
    At 74F indoor stabilized temp I get:
    SH: 58F - 47F = 11F (too high)
    SC: 92F - 79F = 13F (too high).
    So I need to recover charge, right?
    About 17 feet of line set. Did not charge the system, only used what came with the compressor.

    Did anyone else find it odd that the chart in the manual is below what appears to be the operating range?



  2. #2
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    Re: Suction pressure temperature chart Goodman unit

    Sounds like a bad compressor to me.

    Is this a heat pump or A/C?

    What type of compressor is it?

    Can you do a pumpdown test to see if it pulls into a vacuum?
    Last edited by Gary; 21-07-2009 at 04:37 PM.

  3. #3
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    Re: Suction pressure temperature chart Goodman unit

    I thought that R-410a is supposed to run at much higher pressures than R-22. R-410a saturation point at 80 psig is 21F -- which is below freezing! Which would mean that ice would form on the suction line if running at that low a pressure. Why do you think it's a bad compressor? It's an A/C / Heatpump unit. 2.5 tons Goodman unit. Scroll compressor.

  4. #4
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    Re: Suction pressure temperature chart Goodman unit

    TXV or fixed orifice?

    Fixed speed compressor or inverter driven?

  5. #5
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    Re: Suction pressure temperature chart Goodman unit

    TXV and I believe fixed speed compressor.

    Maybe I shouldn't have abbreviated SuperHeat to SH and SubCooling to SC. Note that temps are in Farenheit and pressures in Pounds/SquareInch (gauge).

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    Re: Suction pressure temperature chart Goodman unit

    Your abbreviations are fine.

    With a fixed speed compressor I would expect the saturated suction temp (SST) to be at least 35F below the temp of the air entering the evap coil and I would expect the saturated condensing temp (SCT) to be at least 20F above the temp of the air entering the cond coil.

    The SST is high and (judging by the liquid line temp since I don't know the outdoor temp) the SCT is low.

    This means the compressor is inefficient OR the reversing valve is leaking discharge gas into the suction.

    If the reversing valve is leaking there will be a definite temp rise between the suction temp in and the suction temp out at the valve.

  7. #7
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    Re: Suction pressure temperature chart Goodman unit

    And all of this assumes good airflow through both coils.

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    Re: Suction pressure temperature chart Goodman unit

    I don't know what your skill level is and the above is loaded with assumptions, so it might be a good idea for you to read through the following thread so that we are on the same page and speaking the same language.

    http://www.refrigeration-engineer.co...598#post151598

  9. #9
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    Re: Suction pressure temperature chart Goodman unit

    Quote Originally Posted by onetime View Post
    The Suction pressure temperature chart in the Condensing Unit installation & service reference that came with the unit only goes up to 80 psig...
    I'm wondering if that might be a chart for the heating mode... and there might be another one for the cooling mode?

  10. #10
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    Re: Suction pressure temperature chart Goodman unit

    Thanks Gary. I enjoyed the 101 thread. I'll have to owe you all the numbers until I can get back to my house (new construction). Actually, I can't get realistic numbers until I've insulated the house. I only started up the A/C to make it somewhat tolerable to work in the heat. But looks like I'm in the ballpark as far as charge is concerned. No, there are only two charts, one for saturated suction (50 to 80 psig) and one for saturated liquid (200 to 405 psig). There's R-22 columns and I'm beginning to think that the R-410a column was just added on to the table without also adding rows to the table to cover the R-410a operating range.

  11. #11
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    Re: Suction pressure temperature chart Goodman unit

    i wont to know how to vrv inverter syatem workin procese.

  12. #12
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    Re: Suction pressure temperature chart Goodman unit

    Quote Originally Posted by senaka1982 View Post
    i wont to know how to vrv inverter syatem workin procese.
    Found this post hidden in wrong place here.

    Try Daikin documents, design etc.

    http://www.daikinac.com/commercial/d...c=docs&page=28
    Brian - Torquay, Devon, UK
    I have to stop saying "how stupid can you be?" to my co-workers.
    They're starting to take it as a challenge...

    BASIC MAINTENANCE. If it doesn't move and it should then use WD40. If it moves but it shouldn't then use Duct Tape.

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