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  1. #1
    Join Date
    Dec 2011
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    bedford ind
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    1,085

    minimum lineset length

    Neighbor guy ask me to "look" at his hvac system that another guy put in last year. The lineset is about 3'-4' long. I am thinking the minimum is 8'. Is that correct?

    while I was there they told me their idiot light was blinking 8 times. The guy who installed the system had been back to install a new board. I looked at the instructions from the board as well as the diagnostics on the door, and the diagnostic code showed up to 7 blinks, no 8.

    I gave my neighbor my hourly rate and made an appointment to go back. I don't need an idiot light to find the problem. But I am curious about the 8th blink. Any ideas?

  2. #2
    Join Date
    Jun 2001
    Location
    Moore, Oklahoma, United States
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    3,958
    I'll bet they miscounted, happens all the time.

  3. #3
    Join Date
    Jul 2007
    Location
    Virginia
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    5,021
    Quote Originally Posted by ironpit View Post
    I am curious about the 8th blink. Any ideas?
    Do you have the model number of the unit?
    Instead of learning the tricks of the trade, learn the trade.

  4. #4
    Join Date
    Dec 2011
    Location
    bedford ind
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    1,085
    No model number yet. I was cleaning out my sons garage when the neighbor flagged me down. I did look at the idiot light and it did flash 8 times. I checked it three separate times, including after firing. I could tell the flame sensor was faulty.

    I have yet to go back with my tools to check the system out.

    What about minimum lineset length? I'm thinking 8'.

  5. #5
    Join Date
    Jul 2007
    Location
    Virginia
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    Quote Originally Posted by ironpit View Post
    What about minimum lineset length? I'm thinking 8'.
    I don't ever recall reading about a minimum length.

    You would just have to reduce the refrigerant charge from what the factory charge is - usually for 15 feet of lineset.

    Are you adding the equivalent length of all the fittings into your length calculation?
    Instead of learning the tricks of the trade, learn the trade.

  6. #6
    Join Date
    Dec 2002
    Location
    Arizona
    Posts
    4,240
    Quote Originally Posted by rundawg View Post
    I don't ever recall reading about a minimum length.

    You would just have to reduce the refrigerant charge from what the factory charge is - usually for 15 feet of line set.

    Are you adding the equivalent length of all the fittings into your length calculation?
    Yup, I agree no minimum line length, adjust the charge as stated above. I do however remember reading about minimum line length on a ductless system.
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  7. #7
    Join Date
    May 2005
    Location
    South
    Posts
    580
    I'd look to see if code 7 was relavent. If it said 'shorted winding compressor #1' and it's running fine I'd say it was a mis-count.

    Mini-splits and ductless linesets are sometimes the metering device so they do need to be within spec.

    More info would help, like a brief description of the set up. I'm confused. A lot of emphasis on line set but talk about fire it up and flame sensor.

  8. #8
    Join Date
    Dec 2011
    Location
    bedford ind
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    I'm going to do an official service call tomorrow. I will have specifics then. I read once about a minimum line set length, but don't remember what it was.

    there were a three things I noticed while looking at the system today.

    1. Line set 3' to 4' long.

    2. When they put the furnace in a call for heat, the fire went out immediately, I'm sure because of the flame sensor being dirty.

    3. The diagnostic light was blinking 8 times. I counted them three times. No mistake.
    The paperwork for the board showed diagnostics thru 7, not eight. Same for the
    code on the furnace door.

    Again, I was just there to "look" at the neighbors system. I had no tools with me.
    I will post results tomorrow.
    Last edited by ironpit; 04-07-2012 at 09:50 PM. Reason: goodman unit

  9. #9
    Join Date
    Jul 2007
    Location
    Virginia
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    Quote Originally Posted by ironpit View Post

    The diagnostic light was blinking 8 times. I counted them three times. No mistake.
    The paperwork for the board showed diagnostics thru 7, not eight. Same for the code on the furnace door.
    Could the original board have been changed?

    The Goodman GMNTE furnace diagnostic codes had -

    8 Flashes - Igniter/ Unit Ground
    Instead of learning the tricks of the trade, learn the trade.

  10. #10
    Join Date
    Mar 2009
    Posts
    61

    line length

    minimum line length only for ductless systems LG 50' and so on

  11. #11
    Join Date
    Mar 2007
    Location
    Myrtle Beach, SC
    Posts
    2,919
    If it has a variable speed blower, eight blinks would be 800 CFM. Maybe there is another light?
    Remember, Air Conditioning begins with AIR.

  12. #12
    Join Date
    Dec 2011
    Location
    bedford ind
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    The unit is a GDS80904bna goodman. The furnace is an 09 model.
    The ac was installed last year. Ac is 2 ton. I believe that is a bit of a mismatch.

    The old furnace was a 50,000btu. The dealer replaced it with this 90,000btu.right before he went out of business. He dumped a bunch of equipment on people then retired.
    Approximately 800 -900 sq. ft home. I told them a 55,000 btu furnace was about what they needed. That's when they told me the old one was a 50,000.

    Board was replaced on furnace in the last year. Board #pcb1317-1a. I believe another number on the board was ICM286. Unit was blinking 8 flashes on first call for heat today. No code for 8 blinks.

    One light on board.

    I cleaned the flame sensor and furnace sustained fire until it opened on limit.
    Duct work is not properly sized for a 90,000btu unit. Crawl is approximately 15'' tall. I know they didn't replace the duct.

    They told me previous dealer had replaced the board, inducer motor, blower motor and pressure switch and flame sensor. He did not know what the 8 blinks meant.

  13. #13
    Join Date
    Mar 2007
    Location
    Myrtle Beach, SC
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    2,919
    Quote Originally Posted by ironpit View Post
    The unit is a GDS80904bna goodman. The furnace is an 09 model.
    The ac was installed last year. Ac is 2 ton. I believe that is a bit of a mismatch.

    The old furnace was a 50,000btu. The dealer replaced it with this 90,000btu.right before he went out of business. He dumped a bunch of equipment on people then retired.
    Approximately 800 -900 sq. ft home. I told them a 55,000 btu furnace was about what they needed. That's when they told me the old one was a 50,000.

    Board was replaced on furnace in the last year. Board #pcb1317-1a. I believe another number on the board was ICM286. Unit was blinking 8 flashes on first call for heat today. No code for 8 blinks.

    One light on board.

    I cleaned the flame sensor and furnace sustained fire until it opened on limit.
    Duct work is not properly sized for a 90,000btu unit. Crawl is approximately 15'' tall. I know they didn't replace the duct.

    They told me previous dealer had replaced the board, inducer motor, blower motor and pressure switch and flame sensor. He did not know what the 8 blinks meant.
    ICM makes generic replacement boards. Look up ICM web site, you should find the code there.
    Remember, Air Conditioning begins with AIR.

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