[tferrari]

We have a new Goodman 5 Tonne AC System.

Its really noisy. We removed the filter and it was nice and quiet. We noticed it was really pulling the paper filter into the ducting causing vibration, so we purchased a metal filter instead hoping it would cure it. It improved it but its still way noisier than our old system

Did a bit of research and it seems that the motor may be set too high ( I think there may be 3 speeds min, normal and max).

The installer was not the sharpest tool in the box, we asked him to install our wifi thermostat at the same time and he called him boss and said it was too 'fancy schmancy' for him to install. We ended up calling the helpline for him and they talked him through it. :smile:

The supplier is supposedly ill in hospital.

Anyone out there can tell me which wires to switch to adjust speed, I'd happily pay for the advice.

Handler model is ASPT61D14AC

Pictures of inside handler attached

thanks in advance

 

[user_12345a]

5 ton a/c systems pretty much need to be set to maximum speed for proper airflow.

Reduce the speed and the evap coil may freeze up.


Lower speeds are offered for strip heat as well as pairing 5 ton air handler with a smaller condenser - sometimes done for improved seer rating.

What size is your filter? It may be too small, resulting in air leakage around the frame and excessive noise.

The new air handler is probably moving more air than the old one due to having an ecm motor.

 

[tferrari]

thanks for the speedy response, my filter is 17 1/2 x 29 1/2

I did see the below in the install manual, but cannot find COM, M1 and M2 inside the handler. (wanted to check if he set it at max, the system really is noisy, but almost silent with filter removed)

12.6 Speed Tap Adjustment
ARUF**14** air handlers have multi-speed PSC motors. The color of the wire coming from the motor to the “COM”terminal on the control board defines at which speed the motor will operate. Black wire is high speed, blue wire is medium speed and red wire is low speed. To change speeds, remove the wire attached to the “COM” terminal on
the control board, and swap it with the wire (on terminal “M1” or “M2”) with the color that will give the desired speed.

 

[user_12345a]

If you're filter is one inch thick, it's too small.

The fact that the system is much quiet when the filter is removed confirms this.

I'm assuming you have the filter in the return grill - if my assumption is right, you'll need a larger return air grill or a 4/5" filter downstream.

I would leave it on high speed unless you have a way to verify proper airflow.

The two cheapest ways -> static pressure test (cheapest tools $80-$100) , temperature rise test if the air handler has strip heat in it.

 

[user_12345a]

Your unit has a powerful blower.

Unless your duct system is horrendous, you can probably get away with using tap 4.

For tap 3, static pressure or other airflow is test required for sure. (it's a good idea to test when making adjustments anyway)

You can go down to 350 cfm per ton safely, so 1750 CFM.

On tap 3, static pressure shouldn't exceed 0.4" and ideally should be a little lower. A manometer, tubing and tips are required to test.

After adjustments, check temperature drop across air handler and large insulated refrigerant line for frosting.

 

[SeniorSitizen]

Our 2.5 ton has 750 sq. inches of return filter and makes 0.0 noise. Your 5 ton unit has 516.25 sq. inches and sounds like a hurricane. We have a niece in a large 2 story new house that has the same situation as yours. Her return filter is about 8 ft. from the dining table so they just eat and don't visit much while dining. I'm glad you can see the problem and maybe you need to see another contractor.

 

[Brian085]

What’s the model of the outdoor unit?

 

[tferrari]

the outdoor unit is GSX140601KD

 

[tferrari]

Our 2.5 ton has 750 sq. inches of return filter and makes 0.0 noise. Your 5 ton unit has 516.25 sq. inches and sounds like a hurricane. We have a niece in a large 2 story new house that has the same situation as yours. Her return filter is about 8 ft. from the dining table so they just eat and don't visit much while dining. I'm glad you can see the problem and maybe you need to see another contractor.

Our filter is about 20 feet from our couch yet its still louder than the TV

 

[tferrari]

Your unit has a powerful blower.

Unless your duct system is horrendous, you can probably get away with using tap 4.

For tap 3, static pressure or other airflow is test required for sure. (it's a good idea to test when making adjustments anyway)

You can go down to 350 cfm per ton safely, so 1750 CFM.

On tap 3, static pressure shouldn't exceed 0.4" and ideally should be a little lower. A manometer, tubing and tips are required to test.

After adjustments, check temperature drop across air handler and large insulated refrigerant line for frosting.

Thnaks for the info, its very useful

I was wrong with my Min, normal and max setting. I had not read the manual properly.

You are correct, mine has 4 speed tap settings. From the picture mine is not even set on max (tap 5), its set on tap 4.

So am I correct in saying my options are to either increase the size of the filter installed at the return air filter (I guess by installing one with a larger footprint) or have the static iar pressure tested to see if it can be moved to tap 3 instead.

Thanks to everyone for the useful responses

 

[Missouri Bound]

How large was the old system? Did you have a similar noise problem with that unit?

 

[Brian085]

What kind of filter are you using? What’s the merv rating?

 

[user_12345a]

Thnaks for the info, its very useful

I was wrong with my Min, normal and max setting. I had not read the manual properly.

You are correct, mine has 4 speed tap settings. From the picture mine is not even set on max (tap 5), its set on tap 4.

So am I correct in saying my options are to either increase the size of the filter installed at the return air filter (I guess by installing one with a larger footprint) or have the static iar pressure tested to see if it can be moved to tap 3 instead.

Thanks to everyone for the useful responses

Having an undersized filter can make it more necessary to stay on tap 4.

The filter is too small and reducing the speed alone will not fix that.

Enlarging the filter reduces the pressure the fan has to work against so it moves more air, allowing the speed to be reduced.

Reducing the speed without verifying static/proper airflow is what's problematic.

Even if the the filter is enlarged, it may not move enough air on tap 3.

You'll get the best results if you enlarge the filter and after that am able to reduce the speed.

I would get the static pressure tested or do it yourself before doing anything else.

The testing is useful - not only can total pressure difference be checked, but pressure drop across components like the filter, return pressure alone.

There are lots of good videos showing how to do it on youtube.

 

[digitalplumber]

How big is the house? Is it one story? or even if 2 story, can you add additional return air in other rooms? in the ceilings to assist.

 

[roughneck]

Oversized unit, undersized duct, or a combination of both of those.
Your filter is already too small.
I’m assuming you did not receive any sort of commissioning report with the installation?

 

[user_12345a]

How large was the old system? Did you have a similar noise problem with that unit?

Just going from a psc to x-13 ecm motor and keeping the system size the same can increase noise.

the x-13 does compensate for static to an extent.

 

[sktn77a]

Rule of thumb (here we go again) is 200 sq in of filter per ton. You would need twice the size of filter for correct sizing of your 5 ton unit. Best way to accomplish this would be to add a second return the same size as your current return.

 

[user_12345a]

if i remember correctly 300 fpm is good for returns.

For filters, depends on the pressure drop - 4 or 5" media can go higher than 300 fpm and still be okay.

 

[Missouri Bound]

We have a new Goodman 5 Tonne AC System.

Perhaps I missed it....how large was the old system?
I'm guessing your filter is at the cold air return rather than at the air handler...is that correct?
It seems like a larger, thicker filter could help but if your setup has the filter at the return then it won't be as easy to facilitate.