Reducing airflow from HVAC unit

[Lonnie]

I am not very technical and probably will not be using the correct terms but I will give it my best shot. We just had a new home built and the HVAC guy put in a two zone system. Both are heat pump systems. So we have two units outside, a small 10 SEAR for upstairs and a larger 13 SEAR unit for downstairs and basement and two Goodman air handlers. One 4.0 ton AR48-1 in the basement and a smaller unit upstairs (not sure of the model #)The problem is that the air flow is too high and causes alot of noise upstairs as well as forcing half open doors to shut in some rooms. The system is more than adequate to keep the temperature at 72 degrees during the day. I would like to reduce the fan speed if possible. Any ideas or thoughts?

Thanks,

Lonnie

[Banister Stairwell]

Since this is a new home, your best bet is to discuss this with the homebuilder and/or the HVAC contractor who installed the system. Simply lowering blower speed and reducing the airflow through the indoor coil will cause other problems. More than likely, the solution will lie in modifying the ductwork and registers.

Get the HVAC pros back out there and let them deal with it.

[TURTLE]

This is Turtle.

Give the model number of the unit as to Heat Pump Condenser model number and serial numbers and then the model and serial number of both air handlers inside. Then you could maybe talk about speeds. Till then you in the dark here.

TURTLE

[bitzah]

Not being technical is difficult to answer what is a technical question. Big Picture? Sounds to me like you have a imbalance problem in that the area to be 'conditioned' is not balanced to the amount of air delivered. If as you say,, the system maintains inside conditions in the current ambient temperature (outside) and the air noise is audible, then I suspect you have larger problems than a simple lowering of fan speed. Contact your installer and explain the problem. Whatever you do, do not accept an action to 'fix' the problem that replicates your question in this post.

Cheers

BTZ

[m Ransley]

New home ? Get a second unbiased opinion, call the inspector and a different AC co to test things . Your original co finished the job and was paid they will say it is normal.

[Lonnie]

My father in law built the house for us and I would prefer not to have the contractor who did the work back out there. I will check tonight for the model number and serial numbers of the equipment. I took a look at the manual and wiring diagram for the Air handler in the basement, which is a 4.0 ton Goodman AR48-1, and the fan does have two speeds. The one in the basement is currently set on low. The one upstairs is what I am concerned about. I have 4 bedrooms and two bathrooms. The two larger bedrooms have two air ducts each and the others two. There are two air inputs, one in the hallway directly below the unit and another in the master bedroom. In the attic all ductwork is via the round flexible hosing. If the air handler has two speeds and cycles on infrequently would it really be a problem to change it to the low speed if it is set on high? I read somewhere that if the fan speed is too low you could have condensation or something. Where would I check for that? Also if I just added additional duct vents to the other two rooms, wouldnt that reduce the overall airflow, and accordingly the noise? ( the rooms with two vents are much cooler than the other two rooms.

Thanks,

Lonnie

[Banister Stairwell]

If that's the case, then at least get someone else to come by and check the system out before you start messing with things.

Inadaquate airflow over the indoor coil in air conditioning mode can result in the coil icing up. This is one of reasons I suggest you get a pro to check things out before you make any changes.

It sounds like the system's airflow isn't balanced correctly. You really should get a knowledgeable professional HVAC person out there to re-evaluate your installation and make suitable recommendations to correct your airflow problems.

[m Ransley]

Like Banister said get a pro out, you dont want Icing up.

[TURTLE]

This is Turtle.

The Condenser unit outside model number is what we need along with the serial number. We need both model and serial numbers or air handler and condenser unit[ S ] . Then we can see what you have to tell anything about speeds or seer rating.

TURTLE

[John Barry]

Hi there.

Sounds like you answered part of your initial question. You've discharges into rooms where you have no returns. No wonder the system acts as a door-closer. Good thing you won't be closing those doors!

A friend has similar system with the little discharge connections in the ceiling. On seeing layout, I pointed out that air entering room had to equal air leaving. Response to her by contractor was similar to "this is new technology as seen on This Old House (and we don't need no stinking laws of physics)". No door problem there, though.

Is this a trend, pros, to have mass-airflow from discharge -> suction through rooms?

Regards, John

[Rich]

I'm not a heating expert but the way the house that I just bought has two returns, one in the ceiling of the second floor and one in the downstairs great room. I have two inlets in my master bedroom and one each in the other 3 bedrooms and it works surprising well. I had returns in all my room in my previous house and I didn't expect this to work correctly but it does. One thing I notice is that the door gap at the carpet is larger than I would expect (3/4"X 32 = 24 cubic inches) so maybe this area is sized right for the two incoming registers and that is why it works?

Rich

[Dana]