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Thread: Blower speeds

  1. #1

    Confused

    I recently had a variable speed dual stage furnace installed (Goodman GMV9070CXA).

    I noticed that when it's on high stage the noise at the vents is louder than my old furnace (a 20 year old single stage).

    Now that the hot weather is here and the A/C unit is on the ammount of air blowing through the vents - and the noise seems really excessive.

    I asked the HVAC guy if he could turn the fan speed down and he said no - it will seize the A/C unit.

    I checked into it and found that the cooling fan speed is at the default factory setting, which is the maximum speed the fan can run at.

    Now the goodman manual says that I need about 400CFM per ton. I have a 2 ton A/C unit. So that's 800 CFM

    The unit is currently set at 1429 CFM.

    So what's the deal here? It seems to me that the fan is blowing 179% of what it needs to.

    If I turn it down to 800 CFM it will be nice and quiet.

    But will it seize my Bryant 594D 2 ton air conditioner.


    My wife and I can't atand the noise!

    Please help.

    Thanks,

    Bewaring buyer
    (Typing loud so I can hear what I'm writing).









  2. #2
    Join Date
    Mar 2002
    Location
    Richmond, Virginia
    Posts
    4,264
    I would recommend calling the installing company and voicing your concerns. If they can't satisy you, call someone else, spend the bucks to have it properly setup without complaining to them and chalk it up to experience.
    There is nothing more frightful than ignorance in action....Mark Twain

  3. #3
    Join Date
    Dec 2002
    Location
    Houston,Tx.
    Posts
    15,968
    The unit is currently set at 1429 CFM.

    On a 2-ton I think that's a tad to much the suction is probably off the map.

    Do you live in a humid climate if so you sure won't be removing much humidity.


    But will it seize my Bryant 594D 2 ton air conditioner.
    __________________________________________________ _______________________
    “Experience is a hard teacher because she gives the test first, the lesson afterwards". - Vernon Law

    "Never let success go to your head, and never let failure go to your heart". - Unknown

  4. #4
    Join Date
    Mar 2002
    Location
    Concord, CA
    Posts
    2,635
    Robo has good advice.

    I would add that IF everything you just typed loudly is true then you would appear to know more about HVAC than the installer does! HA!

    And I would add this bit of bad advice. If you think your smart enough to read the manual and adjust the dip switches; and if the air conditioner is most definitely two tons; then go ahead an adjust the dip switches for 800 CFM. 800 CFM is perfect for two tons. Nothing will seize. And IF you're wrong and you break something, don't be a wiener and ask for warranty repairs on something you screwed up.

    If you're in a dry climate, see if you can stand to have a setting that delivers around 1000 CFM. 500 CFM per ton is the cat's meow in dry climates. And turn off the comfort feature that runs the fan in stages. Full bore right away is what you want. There's a bunch of stuff on dry climate AC here. If you're in a humid climate then turn or and/or leave on the comfort setting that ramps the fan. 400 CFM or even 350 CFM per ton is good for humid climates if you have high enough heat load and a TXV. If you don't know what I just said, stick with 400 CFM per ton.

    BTW: If your really are a bewaring buyer, how did you end up with the schlemiel who thinks your unit will have problems at anything less than 700 CFM per ton??? Suspicious buyers are supposed to screen their contractors carefully!

  5. #5
    Join Date
    Sep 2004
    Posts
    3,157
    BTW: If your really are a bewaring buyer, how did you end up with the schlemiel who thinks your unit will have problems at anything less than 700 CFM per ton??? Suspicious buyers are supposed to screen their contractors carefully!

    to funny---he should have spotted that guy a mile away
    or ask Mrs Cleo, she would have known


  6. #6
    Join Date
    Jun 2003
    Location
    Hell Hole Swamp
    Posts
    4,180
    You might want to have that whole system checked out by someone qualified, if the installer wasnt competent enough to set the airflow correctly, which would be the simplest part of the installation, what else did he do wrong? post some pictures of this job if you have the means

  7. #7
    Join Date
    May 2000
    Location
    Indianapolis, IN, USA
    Posts
    34,095
    Extremely rare around here for any installer to set blower speeds. They just leave them where they come from the factory excessive or otherwise.

    Slow that sucker down!

  8. #8
    Join Date
    Sep 2001
    Location
    Vancouver Canada
    Posts
    996
    I think your installer has you a bit confused, I think what he said to you was that it would freeze the unit not sieze the unit. Even with no fan running at all I am sure it would not "sieze" your unit, it certainly would freeze it though. Go ahead and adjust it down to 800 cfm if you have the know how to do so. If not have your installer come back and do it for you.

  9. #9
    Join Date
    Jan 2004
    Posts
    214
    why did you put in a goodman furnace & bryant ac? now you have no warranty. i bet you'll find in your manuals that if you mix & match you blow the warranty. a 2 stage goodman ac system may have performed better because it's designed to work with their 2 stage furnace. sounds like you need a new guy too.

  10. #10
    Join Date
    Mar 2002
    Location
    Concord, CA
    Posts
    2,635
    Originally posted by joeoilman
    now you have no warranty
    You crack me up Joe. Telling the customer such fanciful nonsense... The next thing you know you'll be telling him that elves, hob goblins and Eskimos are real.

  11. #11
    The installer - at least the company is a fairly large installer in my area and others have been happy with their work and their service.

    I did not have any reason to believe that the company would be a problem.

    I think that they have sent underqualified personel to do this job and I will be speaking to the manager on Monday.


    I will not adjust the settings myself even though I know I could do it. I will request that the most senior HVAC installer comes out to check the install thoroughly.

    My first suspicion was when I tried to run the A/C unit the first time after the furnace was installed. It didn't start. Reason: they didn't connect the A/C wire to the thermostat controller on the furnace. That is just stupid - how could they miss that. To me it means they never checked their installation properly. So now I also know that they never adjusted any of the flow rates - they left them all at default. So what else did they mess up?

    I'm not happy!

    Thanks for all the input, it has all been very helpful.


  12. #12
    Join Date
    Mar 2002
    Location
    Concord, CA
    Posts
    2,635
    Well then I formally retract my finger pointing. It's true that a big reputable company (Is there such a thing? ) will on occasion hire someone and promote them to lead installer a little too quickly - not out of ill intent but just out of being so friggin busy.

    It sounds like you have the right plan.

  13. #13
    Join Date
    Apr 2004
    Location
    Niantic, Illinois
    Posts
    545
    Originally posted by bewaringbuyer
    The installer - at least the company is a fairly large installer in my area and others have been happy with their work and their service.

    I did not have any reason to believe that the company would be a problem.

    I think that they have sent underqualified personel to do this job and I will be speaking to the manager on Monday.


    I will not adjust the settings myself even though I know I could do it. I will request that the most senior HVAC installer comes out to check the install thoroughly.

    My first suspicion was when I tried to run the A/C unit the first time after the furnace was installed. It didn't start. Reason: they didn't connect the A/C wire to the thermostat controller on the furnace. That is just stupid - how could they miss that. To me it means they never checked their installation properly. So now I also know that they never adjusted any of the flow rates - they left them all at default. So what else did they mess up?

    I'm not happy!

    Thanks for all the input, it has all been very helpful.

    If the a/c wasn't even connected at the circuit board then I'm sure they didn't run it and check the charge.let alone set the airflow. Sound like they were in a hurry for beerthirty.

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