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  1. #1
    Join Date
    Jul 2012
    Posts
    1,121

    Noisy copeland scroll sounds like bicycle spokes

    I installed a goodman heat pump system on my second floor 3 years ago. Air handler is in attic horizontal ARUF24B14 Goodman, outdoor condenser is a Goodman GSZ13024 Heat Pump. Line set 3/8 x 3/4.
    Line set is 72 feet with a 26' vertical rise on the back corner of the house hidden using gutter downspout. Suction line is well insulated.

    I did add an indoor txv TX2N4.
    Static pressure on supply side .11.
    Return 16" flex from a return cap and tab collar to ceiling return plenum with a 20x20x4 pleated purolator filter.

    System charged in A/C mode to 10 degrees sub cool using my sman3.

    Performance is great. I cheaped out a little with goodman but it works well. Got the unit for a song and dance.

    The copeland scroll at startup in heat mode sounds like bicycle spokes plinking. It does this as the suction pressure dips to approx 40 psig in heat mode. After a minute or so depending on outdoor ambient. Suction pressure slowly rises back up and as the pressure hits approx 52 psig, compressor gets silky smooth and quiet. At first I thought it may be liquid slugging. I added a long vertical rise to the attic. Compressor has a crank heater and accumulator. I don't see a frost line on the accumulator showing liquid standing. Checked outdoor piston for restriction. It's clean.

    Is this normal? Compressor pumps fine. Amps are in line when I checked in the summer in a/c mode.

    It does not make the noise during defrost and back to heat mode. I considered changing the compressor under warranty. I don't want copeland eating the cost of a good compressor if there is not a real problem.

  2. #2
    Join Date
    Aug 2007
    Location
    Northern VA 38 degrees N by 76 degrees W
    Posts
    5,060
    Quote Originally Posted by captaincompressor View Post
    I installed a goodman heat pump system on my second floor 3 years ago. Air handler is in attic horizontal ARUF24B14 Goodman, outdoor condenser is a Goodman GSZ13024 Heat Pump. Line set 3/8 x 3/4.
    Line set is 72 feet with a 26' vertical rise on the back corner of the house hidden using gutter downspout. Suction line is well insulated.

    I did add an indoor txv TX2N4.
    Static pressure on supply side .11.
    Return 16" flex from a return cap and tab collar to ceiling return plenum with a 20x20x4 pleated purolator filter.

    System charged in A/C mode to 10 degrees sub cool using my sman3.

    Performance is great. I cheaped out a little with goodman but it works well. Got the unit for a song and dance.

    The copeland scroll at startup in heat mode sounds like bicycle spokes plinking. It does this as the suction pressure dips to approx 40 psig in heat mode. After a minute or so depending on outdoor ambient. Suction pressure slowly rises back up and as the pressure hits approx 52 psig, compressor gets silky smooth and quiet. At first I thought it may be liquid slugging. I added a long vertical rise to the attic. Compressor has a crank heater and accumulator. I don't see a frost line on the accumulator showing liquid standing. Checked outdoor piston for restriction. It's clean.

    Is this normal? Compressor pumps fine. Amps are in line when I checked in the summer in a/c mode.

    It does not make the noise during defrost and back to heat mode. I considered changing the compressor under warranty. I don't want copeland eating the cost of a good compressor if there is not a real problem.
    The noise is normal the plates in the scroll are chattering while looking for refrigerant to pump, once the suction comes up your noise is gone.

  3. #3
    Join Date
    Jul 2012
    Posts
    1,121
    Yes you are correct. Does this damage or cause accellerated wear on the compressor? Is it a concern?

  4. #4
    Join Date
    Dec 2005
    Location
    Cleveland, OH
    Posts
    2,204
    Did you put a suction trap on that vertical rise?


    Good? Bad? I'm the guy with the gun.
    Good? Bad? I'm the guy with the gun.

  5. #5
    Join Date
    Jan 2007
    Location
    Stongsville Oh
    Posts
    893
    AHU is above condensing unit/ heat pump, trap shouldn't be needed.
    ckartson
    I didn't write the book I just read it!

  6. #6
    Join Date
    Aug 2007
    Location
    Northern VA 38 degrees N by 76 degrees W
    Posts
    5,060
    Quote Originally Posted by ckartson View Post
    AHU is above condensing unit/ heat pump, trap shouldn't be needed.
    I would agree no trap needed.

  7. #7
    Join Date
    Jul 2012
    Posts
    1,121
    I had thought it may be refrigerant migration at first but when I didn't see a frost level on the accumulator or compressor case I abandoned that idea. Compressor has a crankcase heater.

    I tripple evacuated system below 250 microns with nitrogen breaks.
    The system works great. Heating and cooling performance is excellent.

    I had considered adding an outdoor txv.

    I was thinking a VGA charged txv would probably be close to the range I need. Goodman is not very informative on their txv's.

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