New construction home.
Amana compressors, Goodman Furnaces. Digital thermsts.
(1 ac/funrace for downstairs, another ac/furnace for upstairs)
Just under 2 years old. Change filters every month. No problems until now.

Last night my wife heard one of the outside compressors make a "whooshing/buzzing" noise, one so odd she went outside to look at it. Noticed nothing unusual, but then neither of us probably would.

Three hours later, I come home to find the downstairs much warmer than it should be, the compressor runs fine, fan turns as normal, but little to no air coming out of vents downstairs. Upstairs zone is blowing cold and all seems normal up there.

Checked furnace in attic. Fan sounds like it comes on and cold air is evident from small holes around refrig. lines etc. on unit.

Any thoughts as to what might be going on? Thanks in advance for any help.

 

Did you blow a line ???low on freon???
you say the fan runs but no air??????? is inside coil iced up ??? so air dont get throught it ???? need more info here to help you. Dont try and run compressor if low on freon

 

Thanks Ed.
I can't see any eveidence of a blown line outside or in, but will check again when I get home. The weird thing is the fan/compressor runs fine with no noise at all now. The noise my wife heard was a one time thing. Again, I'll check to see if anything looks blown.

I don't know how to check the freon level, but will refrain from running the compressor until I can get it checked.

Any telltale signs the inside coil is iced up? Let me know and I'll check. I have looked along the refrig lines/other lines in and out of the compressor and furnace but see nothing visible, no frost or ice etc. The weird thing is the sound of the furnace turning on when the compressor does, yet little air comes through room vents, not cold and certainly not like it used to.

I've got a tech coming out on Tues. but was hoping to solve it before then. (We're in Texas) Upstairs zone working, so we can always hang up there until then. Thanks again.

 

If the evaporator coil is iced-up, the way to get it ice-free in a matter of just a couple of minutes is to turn the thermostat from COOLING to HEATING. Until when? only until you feel again plenty of air coming through the registers. Then flip t-stat back to cooling.

Ice build-up could be caused by quite a few reasons
* restricted airflow (dirty filter...return grilles closed...a new filter having a very high efficiency)
* a somewhat low refrigerant charge in the system
* too humid a day and you setting the t-stat to a very, very low setpoint (lower than 70F) after the unit having been OFF for quite a few hours
* a defective blower or its capacitor (motor hums but won't spin)
* a defective board (turns outdoor condensing unit ON but not the indoor blower)
* a malfunctioning (or partially plugged) expansion device
* a clogged filter dryer in the liquid line

to mention a few.