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  1. #1
    Join Date
    Jun 2012
    Posts
    6

    Need Advice Please

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    Name:  air handler.jpg
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    In May we had a Nordyne IQ Drive system installed with all new duct work and 2 return vents. The air handler sits in the middle of our home which our living area is centered around. See attached pictures for location of air handler & vents.

    Problem #1: When the system ramps up to higher blower speeds it sounds like we are in a wind tunnel, when ramping down there is a high pitched whining noise, low speeds sound tolerable.

    Problem # 2: There is no ramping up, when the air handler is off and comes back on, it is at high fan speeds, and there is no ramping up.

    Problem #3: In the Florida summer, humidity averages 60%.

    I have contacted the installation company and they have tried to remedy these issues to no avail. Finally, they have admitted this is not right and have agreed to replace the system with another brand.

    Question #1. Do all variable speed air handlers tend to be loud at the higher blower speeds?

    Question # 2. We have a 4 ton system, the company insists this is the correct size and a 3 ton would not cool enough. Our home is only 1752 sq. They said they have done the calculations and it came out we needed 3 tons, so they upped it to 4. Is that oversized? Would a 3 ton cool enough and have better humidity control?

    Question # 3. Any suggestions on what brand AC system that has a quiet air handler?

    Thank you for any help with this.

    Brandy

  2. #2
    Join Date
    Aug 2012
    Posts
    2,666
    Typical to oversize in hot humid weather because costomer wants to be chillin when its 100 and 90 percent humidity outside. This practice reduces complaints but will increase your electric bill. Post the brand name and model number to get help on specific equipment.
    Sinse the comp. allready agreed to replace equipment look into whisper quiet models may up the cost however.

  3. #3
    Join Date
    Aug 2012
    Location
    North Dakota
    Posts
    518
    dont ever upsize you'll loose the ability to dehumidify the units run time dictates its efficency (the longer the run the more eff.) id rather go down never up

  4. #4
    Join Date
    Apr 2010
    Location
    NC Sandhills
    Posts
    409
    Where your unit is located, it will be difficult to make it as quite as a single speed blower is. Most likely your supply ducting is all original, and could have been undersized to begin with which means it is more undersized for a higher seer unit. A single speed blower is going to try to put out x cfms at y rpm, it cant adjust itself. A variable speed blower is going to try as hard as it can to put out x cfms and will adjust its rpms to what ever is needed to do it (although it has a safety limit). If the duct work is undersized that blower is going to have to run at high speed all the time to move the air. With your return plenum being in the middle of your living space it will be difficult to fully address the issue. If you take out the filter and look into the return is it metal or wood? You can try putting sound deadening styrofoam or lining the return with insulation, to cut down on noise some. I like the Trane hyperions but in this case if you change brands do NOT get that air handler as its blower is on the return side and would make the noise worse.

  5. #5
    Join Date
    Aug 2012
    Posts
    2,666
    Quote Originally Posted by mechanical'al View Post
    dont ever upsize you'll loose the ability to dehumidify the units run time dictates its efficency (the longer the run the more eff.) id rather go down never up
    Thats easy to say when your in North Dakota.
    Down in La. you've got houses that are 120 yrs old without any insulation and leaky like a hocky goalie. Why is my house 80 deg. all summer long? Why is my bill 500 bucks a month?

  6. #6
    Join Date
    Jun 2003
    Location
    Madison, WI/Cape Coral, FL
    Posts
    6,471
    Quote Originally Posted by Brandy View Post
    Name:  2 return vents.jpg
Views: 134
Size:  30.8 KB
    Name:  air handler.jpg
Views: 163
Size:  29.9 KB

    In May we had a Nordyne IQ Drive system installed with all new duct work and 2 return vents. The air handler sits in the middle of our home which our living area is centered around. See attached pictures for location of air handler & vents.

    Problem #1: When the system ramps up to higher blower speeds it sounds like we are in a wind tunnel, when ramping down there is a high pitched whining noise, low speeds sound tolerable.

    Problem # 2: There is no ramping up, when the air handler is off and comes back on, it is at high fan speeds, and there is no ramping up.

    Problem #3: In the Florida summer, humidity averages 60%.

    I have contacted the installation company and they have tried to remedy these issues to no avail. Finally, they have admitted this is not right and have agreed to replace the system with another brand.

    Question #1. Do all variable speed air handlers tend to be loud at the higher blower speeds?

    Question # 2. We have a 4 ton system, the company insists this is the correct size and a 3 ton would not cool enough. Our home is only 1752 sq. They said they have done the calculations and it came out we needed 3 tons, so they upped it to 4. Is that oversized? Would a 3 ton cool enough and have better humidity control?

    Question # 3. Any suggestions on what brand AC system that has a quiet air handler?

    Thank you for any help with this.

    Brandy
    Start by reducing the air flow by slowing the blower down to get a very cold coil. The fan will make less noise and remove more moisture. During peak cooling loads, you 4 ton ac with provide <50%RH and not be so noisey. A 3 ton may do a litle better during moderate cooling loads. During low/no cooling loads, you could have a 2 ton and have high humidity. I thought the IQ had a V
    S blower which can easily be slowed. Keep us posted.For real <50%RH during low/no cooling, get a whole dehumidifier like the Ultra-Aire 70H.
    http://ultra-aire.com/index.php?opti...id=65&Itemid=5

    Regards TB
    Bear Rules: Keep our home <50% RH summer, controls mites/mold and very comfortable.
    Provide 60-100 cfm of fresh air when occupied to purge indoor pollutants and keep window dry during cold weather. T-stat setup/setback +8 hrs. saves energy
    Use +Merv 10 air filter. -Don't forget the "Golden Rule"

  7. #7
    Join Date
    Aug 2012
    Posts
    2,666
    I think she used us, I feel so cheap.

  8. #8
    Join Date
    May 2000
    Location
    Indianapolis, IN, USA
    Posts
    34,245
    Anytime you pull 1600 CFM right out the bottom of the air handler like that, it is going to be noisy. Insulation the walls of that box the AH is sitting on will help. But she can try any brand on the market, ain't gonna make a bit of difference.

  9. #9
    Join Date
    Jan 2004
    Location
    Lancaster PA
    Posts
    68,174
    Quote Originally Posted by BaldLoonie View Post
    Anytime you pull 1600 CFM right out the bottom of the air handler like that, it is going to be noisy. Insulation the walls of that box the AH is sitting on will help. But she can try any brand on the market, ain't gonna make a bit of difference.
    Nope. And if they under sized the supply, it just makes it worse as the VS blower has to rev up to higher speeds to try and move 1600 CFM.

    OP, what size A/c did you have before.
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  10. #10
    Join Date
    Aug 2012
    Location
    North Dakota
    Posts
    518
    ya point well taken toocool though when doing your load calc. those figures (average highs mean) are accounted for???? for your neck of the woods so you will still up-size from there????

  11. #11
    Join Date
    Aug 2012
    Posts
    2,666
    Quote Originally Posted by mechanical'al View Post
    ya point well taken toocool though when doing your load calc. those figures (average highs mean) are accounted for???? for your neck of the woods so you will still up-size from there????
    Yes.

  12. #12
    Join Date
    Aug 2012
    Location
    North Dakota
    Posts
    518
    wouldnt it be only nessary to up-size to evap to address the latent heat gain

  13. #13
    Join Date
    May 2004
    Location
    south louisiana
    Posts
    3,200
    toocoolforschool says..what load calc? we use our fingers covering house from across the street to size units.
    LOL! I've been here in La. for a looong time.

    OP I have pretty much the same physical set up with vs ahu for 2 ton
    its very quiet. I used ductboard in the bottom of the return to quiten air flow.
    my R/A is in living room, ahu in closet.

    go back to post #6 as to humidity control.
    unless your house and or ducts are really leaky, you should be ok with
    3 tons. have them mastic seal your ductwork & caulk inside the return box.
    if you want to quiten the air at the return, line return with ductboard.

    best of luck.
    The cure of the part should not be attempted without the cure of the whole. ~Plato

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