- My Forums
- Tiger Rant
- LSU Recruiting
- SEC Rant
- Saints Talk
- Pelicans Talk
- More Sports Board
- Fantasy Sports
- Golf Board
- Soccer Board
- O-T Lounge
- Tech Board
- Home/Garden Board
- Outdoor Board
- Health/Fitness Board
- Movie/TV Board
- Book Board
- Music Board
- Political Talk
- Money Talk
- Fark Board
- Gaming Board
- Travel Board
- Food/Drink Board
- Ticket Exchange
- TD Help Board
Customize My Forums- View All Forums
- Show Left Links
- Topic Sort Options
- Trending Topics
- Recent Topics
- Active Topics
Started By
Message
Replaced AC- New one very loud
Posted on 8/21/22 at 10:48 am
Posted on 8/21/22 at 10:48 am
I had a large water oak removed at one of my rent houses. The two ton unit was barely keeping up and it was old. But, still working.
The salesman from a large company came out and suggested we put in a 2.5 ton to make up for the tree loss. Plus I'm having them blow in insulation. The house is 1200 sf with 8 foot ceilings. Replacement went fine, excellent installation.
Problem is that the new air handle is loud as a train/trane. It is in a closet in the den with the return air in the hallway. Not sure what can be done. Was I remiss for now asking about the noise level? Or did the salesman fail to consider this?
I discussed short cycling with a larger unit and he said that would not be a problem. I plan on calling tomorrow to see if they have suggestions.
Any thoughts?
The salesman from a large company came out and suggested we put in a 2.5 ton to make up for the tree loss. Plus I'm having them blow in insulation. The house is 1200 sf with 8 foot ceilings. Replacement went fine, excellent installation.
Problem is that the new air handle is loud as a train/trane. It is in a closet in the den with the return air in the hallway. Not sure what can be done. Was I remiss for now asking about the noise level? Or did the salesman fail to consider this?
I discussed short cycling with a larger unit and he said that would not be a problem. I plan on calling tomorrow to see if they have suggestions.
Any thoughts?
9
Posted on 8/21/22 at 11:43 am to ItzMe1972
Could be several thigs - blower motor or fan cage out of balance, loose motor mounts, loose fan/evap unit mounts, piece of ductwork not secured, etc.
Since this is a new installation, I'd get the installing company to fix whatever is wrong.
Since this is a new installation, I'd get the installing company to fix whatever is wrong.
Posted on 8/21/22 at 1:25 pm to ItzMe1972
Slow down the fan on control board
Posted on 8/21/22 at 1:30 pm to ItzMe1972
most airt handlers are for multiple ton units and you adjust the fan speeds for the size you need.
it sounds like yours is running 3 tons of air and needs to be set lower down to the medium speed.
its also that newer units are way more efficient and part of that is better airflow so the noise may not change all that much after adjusting the fan.
there are other things you can do such as staple sound deadening foam in the box area under the unit. that will help out a lot
it sounds like yours is running 3 tons of air and needs to be set lower down to the medium speed.
its also that newer units are way more efficient and part of that is better airflow so the noise may not change all that much after adjusting the fan.
there are other things you can do such as staple sound deadening foam in the box area under the unit. that will help out a lot
Posted on 8/21/22 at 6:26 pm to ItzMe1972
As stated/recommended start by reducing the air handler fan speed, they are by default set at factory at the highest setting - it’s the commissioning HVAC tech’s responsibility to adjust the speed as needed on site after install if appropriate.
A couple other things. If the duct work was sized for a 2 ton unit and 2.5 ton unit installed it’s still only going to deliver 2 tons of air capacity, and system may be loud b/c of high static pressure associated with trying to force 2.5 tons of air through 2 ton sized ducts. You can ask them to measure the static pressure to see if it is within manufacturer’s specs which will be provided in the installation manual (don’t be surprised if they look at you like you crazy).
Second thing, how large is the return duct/plenum? Is it significantly undersized for the 2.5 ton unit, if so higher noise can be the result.- a return side static pressure reading will indicate if it’s undersized.
Lastly, what MERV filter do you have in the unit? High MERV pleated 1 inch filter? If so, try a less restrictive fiberglass spun MERV 4 filter and see if that helps with noise reduction.
A couple other things. If the duct work was sized for a 2 ton unit and 2.5 ton unit installed it’s still only going to deliver 2 tons of air capacity, and system may be loud b/c of high static pressure associated with trying to force 2.5 tons of air through 2 ton sized ducts. You can ask them to measure the static pressure to see if it is within manufacturer’s specs which will be provided in the installation manual (don’t be surprised if they look at you like you crazy).
Second thing, how large is the return duct/plenum? Is it significantly undersized for the 2.5 ton unit, if so higher noise can be the result.- a return side static pressure reading will indicate if it’s undersized.
Lastly, what MERV filter do you have in the unit? High MERV pleated 1 inch filter? If so, try a less restrictive fiberglass spun MERV 4 filter and see if that helps with noise reduction.
Posted on 8/21/22 at 8:09 pm to CrawDude
I've tried a pleated filter and a fiber filter, didn't notice any difference. The filter size is 24X14.
I'll call the company tomorrow. The salesman is a former installer. I may see if they come up with fan speed and duct sizing on their own. Otherwise I will.
The company is a large operation and should have the resources to figure it out, we'll see.
Thanks for all the replies!
I'll call the company tomorrow. The salesman is a former installer. I may see if they come up with fan speed and duct sizing on their own. Otherwise I will.
The company is a large operation and should have the resources to figure it out, we'll see.
Thanks for all the replies!
This post was edited on 8/21/22 at 8:10 pm
Posted on 8/21/22 at 9:00 pm to ItzMe1972
Your return air duct(s) should be supplying about 400 cfm per ton to the air handler - or 1000 cfm for a 2.5 ton unit. This table might help
If a round flex duct is attached to the 14 x 24 return grill you’d need about an 18 in diameter duct to supply about 1000 cfm of return air. Anything considerably smaller would be “starving” the air handler of sufficient air and would increase noise. Anyway something to discuss with the installer if the problem is not strictly mechanical.
If a round flex duct is attached to the 14 x 24 return grill you’d need about an 18 in diameter duct to supply about 1000 cfm of return air. Anything considerably smaller would be “starving” the air handler of sufficient air and would increase noise. Anyway something to discuss with the installer if the problem is not strictly mechanical.
Posted on 8/21/22 at 9:04 pm to ItzMe1972
I’ve seen this before.
The newer air handlers with higher seer ratings push more air faster, as opposed to less air slower. I think this makes them louder. It sounds like a ‘big fan’?
The newer air handlers with higher seer ratings push more air faster, as opposed to less air slower. I think this makes them louder. It sounds like a ‘big fan’?
Posted on 8/22/22 at 8:04 am to baldona
It sounds like a ‘big fan’?
---
Yes
---
Yes
Posted on 8/22/22 at 8:32 am to ItzMe1972
Some units in areas like hallways that are set in "closets" can be pretty loud.
I had that issue with my first unit I installed in 92 and what I did to help with the noise was take pieces of common wall insulation and put it with the insulation facing out, stapled it to the floor and wall area of the return air to help muffle some of the sound. That area, before I added the insulation was all hard surfaces, so it did help.
I had that issue with my first unit I installed in 92 and what I did to help with the noise was take pieces of common wall insulation and put it with the insulation facing out, stapled it to the floor and wall area of the return air to help muffle some of the sound. That area, before I added the insulation was all hard surfaces, so it did help.
This post was edited on 8/22/22 at 8:34 am
Posted on 8/22/22 at 8:41 am to baldona
quote:
I’ve seen this before. The newer air handlers with higher seer ratings push more air faster, as opposed to less air slower. I think this makes them louder. It sounds like a ‘big fan’?
Newer HVAC air handlers/furnaces have EMC blower motors vs the PSC blower motors commonly found in units that are more than a few years old. EMC motors are more energy efficient and therefore increase SEER rating, but are also multitudes more expensive than PSC motors to replace if they fail.
OP’s new unit likely has a EMC constant torque blower motor. Those motors will ramp up to try to maintain a constant air CFM output, increasing in noise, if there is an increase static pressure due to some sort of air restriction in the system.
This 6 minute Y/T video demonstrates this including the noise increase. LINK
This post was edited on 8/22/22 at 5:22 pm
Posted on 8/22/22 at 9:17 am to ItzMe1972
Talked to salesman.
First thing he suggested was turning the fan down. He said those hall installed units have lots of air turbulance. He scheduled a service call.
First thing he suggested was turning the fan down. He said those hall installed units have lots of air turbulance. He scheduled a service call.
Posted on 8/22/22 at 9:37 am to ItzMe1972
bigger tonnage without larger duct work means it will be louder. Without larger ductwork the supply velocity will be 25% more.
You can check to see if the air handler is set to 400 or 450 cfm/ton and change it to 325-350 cfm/ton. that will help reduce the noise.
You can check to see if the air handler is set to 400 or 450 cfm/ton and change it to 325-350 cfm/ton. that will help reduce the noise.
Posted on 8/23/22 at 7:57 am to ItzMe1972
Followup:
The tech came out yesterday and agreed the unit was very loud. He called up the model number in his Ipad and adjusted the fan speed down to 1500+ CFM. Not sure, but think it was set to 1800+.
He said that should help with humidity. I'm sure he was referring to no short cycling.
Much quieter. I am having additional insulation blown in tomorrow.
Tech said to see how it does when the heat comes back in September or next summer. I have a one year warranty and they'll be back to tweek if necessary.
The tech came out yesterday and agreed the unit was very loud. He called up the model number in his Ipad and adjusted the fan speed down to 1500+ CFM. Not sure, but think it was set to 1800+.
He said that should help with humidity. I'm sure he was referring to no short cycling.
Much quieter. I am having additional insulation blown in tomorrow.
Tech said to see how it does when the heat comes back in September or next summer. I have a one year warranty and they'll be back to tweek if necessary.
This post was edited on 8/23/22 at 7:59 am
Posted on 8/23/22 at 9:03 am to ItzMe1972
quote:
The tech came out yesterday and agreed the unit was very loud. He called up the model number in his Ipad and adjusted the fan speed down to 1500+ CFM. Not sure, but think it was set to 1800+. He said that should help with humidity. I'm sure he was referring to no short cycling
Might have misheard him - criteria for air flow for most of the country is 400 cfm per ton (1000 cfm for a 2.5 ton system), 350 cfm per ton for humid areas (875 cfm for 2.5 ton) and in very hot, dry areas (450 cfm per ton, 1125 cfm for 2.5 tons).
Air flow for your model air handler for different blower motor speeds will be provided in air handler/furnace installation manual which they should have given you a copy of. I don’t think your air handler would be capable of producing 1500 to 1800 cfm - my 4 ton furnace can but not a 2.5 ton unit.
Slowing the air handler blower speed helps to decrease humidity by keeping the return air in longer contact time with the cold evaporator coil thereby increasing latent heat (=humidity) removal.
Glad to hear you got significant noise reduction.
Posted on 8/23/22 at 9:14 am to ItzMe1972
Do you have a high velocity system? If not, as the previous post says you should be between 800 and 1000cfm.
Page 1 of 1
Popular
Back to top
Follow TigerDroppings for LSU Football News