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  1. #1
    Join Date
    Apr 2012
    Posts
    9

    Heat pump noise/??high pressures

    Hi everyone,

    7 year old Ducane Seer 13 4 ton heat pump, ADP indoor unit.

    Works flawlessly. For about 4 months, there has been an intermittent "rattling/vibrating" noise heard indoors while running. HVAC guy thinks noise is generated by the outdoor unit, and travels indoor thru the tubing. Seems right, compressor seems louder, and I can feel vibration at the tubing connected to the outdoor unit. He says bad compressor, replace it.

    While running heat mode, outdoor temp mid 40s, high side pressure varies from 300 to 450. Several times when pressure hit 450, there is a loud hissing at the outdoor unit, and pressure drops to 300, almost as though an internal pressure relief valve has opened. The pressure remains at 300, and the hissing continues, until that cycle ends. Still heats. Low side pressure around 130-140.

    I'd hate to have him replace the compressor needlessly. Does this sound like compressor, or something else?

    Thanks. Gene

  2. #2
    Join Date
    Jan 2011
    Location
    Metro Atlanta
    Posts
    777
    get a second opinion if you don't trust the first one.

    I know my old company did free second opinion calls as long as, after we are done with our assessment of the issue you show the first opinion, or we bill you.
    The opinions expressed by me are not that of my employer.


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  3. #3
    Join Date
    Oct 2011
    Location
    Las Vegas, NV
    Posts
    509
    Quote Originally Posted by Gene2 View Post
    Hi everyone,

    7 year old Ducane Seer 13 4 ton heat pump, ADP indoor unit.

    Works flawlessly. For about 4 months, there has been an intermittent "rattling/vibrating" noise heard indoors while running. HVAC guy thinks noise is generated by the outdoor unit, and travels indoor thru the tubing. Seems right, compressor seems louder, and I can feel vibration at the tubing connected to the outdoor unit. He says bad compressor, replace it.

    While running heat mode, outdoor temp mid 40s, high side pressure varies from 300 to 450. Several times when pressure hit 450, there is a loud hissing at the outdoor unit, and pressure drops to 300, almost as though an internal pressure relief valve has opened. The pressure remains at 300, and the hissing continues, until that cycle ends. Still heats. Low side pressure around 130-140.

    I'd hate to have him replace the compressor needlessly. Does this sound like compressor, or something else?

    Thanks. Gene
    Sounds like something else, but you will need a compressor soon if the issue isn't found and repaired. Those pressures are too high for R 22, which I'm assuming it's R 22 due to the age. Your contractor should be able accurately diagnose such an issue, and if not, perhaps find a different contractor. Your compressor's internal bypass relief is doing its job. The cause of the high head pressure needs to be found.

    Sent from my PG86100 using Tapatalk 2

  4. #4
    Join Date
    Jul 2010
    Location
    nebraska
    Posts
    1,629
    Quote Originally Posted by suBcools View Post
    Sounds like something else, but you will need a compressor soon if the issue isn't found and repaired. Those pressures are too high for R 22, which I'm assuming it's R 22 due to the age. Your contractor should be able accurately diagnose such an issue, and if not, perhaps find a different contractor. Your compressor's internal bypass relief is doing its job. The cause of the high head pressure needs to be found.

    Sent from my PG86100 using Tapatalk 2

    Exactly right. If your service company doesn't know what causes high pressure in heating mode it's time to find another one.

  5. #5
    Join Date
    Jan 2004
    Location
    Lancaster PA
    Posts
    67,913
    Being able to do a compression ratio of 3 to 1, probably not a compressor problem. Of course, that depends if its an R410A or R22 system. Along with where he is taking his readings from.
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  6. #6
    Join Date
    Apr 2012
    Posts
    9
    Hi everyone,

    Thanks so much for the replies, my gut sense was not to go for the new compressor.

    System is R-22. It has an orifice, not TXV, on indoor unit.

    For my info (not DIY, I just like to understand things), what are we likely looking at? Clogged orifice or filter-drier?

    Thanks again. Gene

  7. #7
    Join Date
    Oct 2011
    Location
    Las Vegas, NV
    Posts
    509
    Quote Originally Posted by Gene2 View Post
    Hi everyone,

    Thanks so much for the replies, my gut sense was not to go for the new compressor.

    System is R-22. It has an orifice, not TXV, on indoor unit.

    For my info (not DIY, I just like to understand things), what are we likely looking at? Clogged orifice or filter-drier?

    Thanks again. Gene
    Impossible to tell without more information. However, I will say that the majority of the time a high head pressure issue in heating mode is usually the result of low indoor airflow, for one reason or another.

  8. #8
    Join Date
    Aug 2004
    Location
    North Richland Hills, Texas
    Posts
    14,914
    It is extremely unlikely that the compressor is the problem, though in the process of replacing the compressor, it is very likely that the actual problem would be cleared up.
    If more government is the answer, then it's a really stupid question.

  9. #9
    Join Date
    Apr 2012
    Posts
    9
    Quote Originally Posted by suBcools View Post
    Impossible to tell without more information. However, I will say that the majority of the time a high head pressure issue in heating mode is usually the result of low indoor airflow, for one reason or another.
    This was checked, indoor coils cleaned and filter is just about new. Nothing has changed in ductwork.

    Thanks. Gene

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