Noisy air velocity on AC unit.

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  #1  
Old 10-17-07, 06:16 PM
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Noisy air velocity on AC unit.

Okay I can't find my original post I am not sure how it disappeared.

When we moved in we had a 3 ton AC unit that was very unreliable but it was quiet. Then we decided to get another unit after more than enough days of it not working in the Florida heat. At the same time we thought in the near future we would be putting in an addition. At that point we got a 5 ton AC unit that was put into a 1900 square foot house in anticipation for another 900+ square foot addition as we were told a 5 ton would be good for that square footage of a house.

At the point of installation we noticed the air velocity was MUCH louder when cooling E.G. the change from a soft air breeze to a loud bus terminal. The noise is not mechanical it is pure air velocity noise. Any vent half closed gives a loud whistle. Any vent left open just get a very loud whoosh of air. most of my vents are about 12x12 some older original from the 70's and others new replacements (mainly for the vents that would not stay partially opened or closed).

I know when they put in the new A/C unit they ran new accordian style round ducting.

Now our 900 square foot addition is probably a couple of years off.... Do I have to live with this noise for 2 years? Will this noise go away with the added square footage and extra ducting that is in place?

Help because the first thing any guest mentions when they are over is how loud this is to try and talk over.

BTW the 2 parts are -
AEPT060-00C-1 for the air handler and CPLJ60-1A for the ? Heat pump ? (I thought this was actually an air conditioner not sure why goodman classifies it as a heat pump or what the difference is)
 
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  #2  
Old 10-18-07, 06:04 AM
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The CPLJ series are heat pumps. A heat pump can both heat and cool. The heating is more efficient than regular heat strips.

Your main problem, I believe, is trying to use a 5 ton air handler with a 3 ton duct system. Air velocities will increase and produce more noise. The solution is to add more ducts and/or increase the diameters of existing ducts. In short, the duct system needs to be upgraded to 5 tons.
 
  #3  
Old 10-18-07, 11:00 AM
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Most air handlers have 3 or 4 speed motors in them. Usually the AC is using the highest speed and the heat the lowest speed. You could probably use one of the other speed taps and slow the motor down for the AC until the room addition is finished. You may want your HVAC contractor to do this so they can make sure it is still getting enough air across the coils.
 
  #4  
Old 10-18-07, 06:05 PM
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jim-connor, I neglected to mention the ducting - Sorry that would help when telling you I have noise huh? They took up a bunch of accordian style ducting into the attic as well. I am sure this guy didn't reuse anything of the original system at all as he even relocated my air returns to the ceiling (they were near the ground) letting me know that this way I would have the warmest air returning out of the room and not the colder heavier air (which to me makes sense if its correct or not I don't know).

cjett so your saying they can lower the speed but they have to keep the speed just fast enough to put air across the coils? Is this something that is just trial and error? Is there a potential for damaging my A/C unit if i get an A/C technician that does not know what he is doing?
 
  #5  
Old 10-19-07, 11:45 AM
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Wink

Dont know the home or know what the AC load is there. But first down in FL 5 ton for a 2800 sq ft home is over kill for sure Id say. Also that heat pump dont pay down there. for the time you need heat just use the electric is all Put the rest of the $$$ in the bank for the added cost of the heat pump . Yes you can slow the blower down some . Play with it and see. All of the new V.S blowers have a humidistat control to slow the blower down . This way it will take out more humidity for you. Also tha big and over size unit will run to short of time and not get the humidity out of the home like it should.
 
  #6  
Old 10-19-07, 08:51 PM
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Well we have not had any humidity problems at all. I would have complained the second that happened because that is one part of florida I can't stand.

Are you guys saying this here -

http://www.acdirect.com/xcart/images...EPT_ss-365.pdf

On page 6 is thouse the dip switches for changing the blower speeds on dip switches 5-6 and 7-8? Is it really as simple as opening the unit and flipping the dip switches?
 
  #7  
Old 10-20-07, 11:39 AM
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If that is the unit that you have, it would appear so.
 
  #8  
Old 10-22-07, 06:21 AM
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Freezing

Don't you run into a problem with freezing coils if you turn the air speed down?
 
  #9  
Old 10-22-07, 10:53 PM
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OK, we have several problems here. You added a larger unit in anticipation of adding a room in the future. You also added a larger unit without doning alot of homework.

The first problem. You have a 5 ton system on a 3 ton house. As far as noise, your stuck now. You can not slow air down through your system. If your coil isn't an ice maker now, it will be it your slow the air across that coil. There is a fine balance from cold air to ice cubes. Leave your airflow alone and accept that until you add more registers, your stuck with sound.

Now, the second issue. When you oversize any AC system in a house, you lose humidity control. You need to have your system run for a minimum of 7 to 10 minutes every cycle on. This will allow your coil to lower air temp and bring your dew point down. A lower dewpoint means a less sticky house. If your unit turns on for 4 minutes and cools the house then turns off, your not "ringing" the water out of the air and your house will always feel sticky. You need to move enough of the air in your house across the coil to get the dehumidification you can. The larger the Deata T, the better you are.
 
  #10  
Old 10-23-07, 06:52 AM
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Yes if you have the dip switch there. open the blower door and set the lower . Read the paper work for the cfm you can set them for.

Read note #5 there on page#6 I like to use a humidistat on the V/S blower to slow it down . This helps with the humidity control in the home .
 
  #11  
Old 11-02-07, 09:28 AM
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The Goodman AEPT060 is a variable speed A/H with a TXV. We've sold and installed some. They have awesome air flow.
I'd say set your dip switches for the lowest amount of air flow and see what happens. That's probably about all you can do with it anyway. If it runs fine great, if the evaporator coil freezes up, change dip switch setting for more air flow and see what happens. You may have to live with the noise.
Keeping your filter(s) clean at all times will also reduce the chances of your coil freezing up.
 
  #12  
Old 11-22-07, 01:08 PM
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what happens with a over sized a/c. the system will not be effiant,will not remove moisture,will waist energy,will cycle so much that it will wear down the parts of the system quicker then norm,will have excessive airflow in house.
what did the load calculation call for or was it a guess.
lower the fan speed some, add a bypass damper,replace registers with ones that throw more air (less velocity).lower the fan to much will cause coil freeze and next comes the water.
 
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