AC fan & airflow

Oct 20, 2004 20 Replies

After running for any length of time ( like overnight) air stops coming out of our vents. The condenser outside is running and I hear the fan in the attic running but there is very very little air movement. If I shut down the unit for awhile and restart it there is good/normal airflow. I had an AC man come out and he said our coils were clean and the unit seemed to be operating fine with good airflow, but this morning, we were back to no air movement.



Any ideas would be appreciated. JD


The evaporator is icing up. There could be several possible problems. Unless you have the experience and tools I suggest that you call your local HVAC professional to find and correct the problem.

find a new a/c man....preferably a *competent*, licensed, insured, professionally trained, HVAC technician...instead of the cheapest moonlighting hack you can find.

I see you did have someone come out. Clearly he was not a good one. While air flow and dirty coils are both possible issues, they are not the only ones. You need someone better. Like maybe average. :)

What's the over night temperatures?

And try to have the AC unit in the frozen no air state when he's coming.

You can have yours frozen when I get there and you can pay for me for the extra hour or so to defrost the damn thing so I can diagnose *ALL* the problems, not just a symptom.

What would be freezing in the "blower" unit? Why would that stop the air flow? What should I look at in the blower unit to try and give the or any AC man some direction and specific simptoms? The outside condenser unit is running fine, when there isn't any air coming out, wouldn't that be the part that freezes up? JD

The only thing *you* do is shitcan the hack that worked on it and left you with the same symptoms/problem. Then call the wholesale supply house that carries the brand of equipment you have and ask them "Who's the best technician you got?" (Who would they call to work on the system in their family's home??). Beyond this, there is nothing for the DIY to do unless they are licensed, hold an EPA card, have all the appropriate tools/instruments, and have the training, education and experience to be able to correctly use them without hurting themselves or the equipment.

Water from the air condensing on the coils then freezing builds up until it covers and blocks the air flow.

Just tell them what you told us. You don't need to tell them how to fix it, all you need to is tell them why you called. It does not cool because after running a while no air comes out. Any real tech will know what that means.

No it is the inside part that gets cold to cool your home. The outside part actually heats up during use.

YOU dont need to do a thing, but call someone that has a clue, since its obvious as hell the first guy didnt.

Sounds like probly ice is forming on the indoor coils--and means its time for a check up.

Suggest call in a pro, he will take temperature and perhaps some air velocity readings, and definately will check high and low side refrigerant pressures and also perhaps check for leaks........

A *real* pro will give you a copy of these readings upon asking--in fact, best when calling any outfit to let em know upfront you wish to get a hard copy of this info....so far as hack outfits go this will help in separating the wheat from the chaff at the get go.

Only if you want to pay for an extra hours work or more! (good chance the service person will need to defrost the unit)

gerry

That sounds fair. I'd rather pay for an extra hour of labor instead of having the repair guy not see the actual problem, misdiagnose it, charge me, and then have to pay a lot more for another service call later. That's what happened here.

Had another guy come over and he diagnosed it over the phone as icing up. We ran the fan with AC off and then turned the unit off two hours before he arrived. When he started examining the system he discovered the vents I had turned off in several unused rooms restricting air flow ( new information to me that you can't just close vents), as well as low outside temps, and a pound low on Freon. We will see if this has fixed it we will know in a couple of days. Thanks for the direction. JD

But did he find the leak and repair it? If not, you'll just go through the same thing later on. The leak doesn't fix itself and only gets worse.....

Leaks (to an AC guy) are like cavities to a dentist. They don't get smaller on thier own.

A leak is presumptive it was ever charged correctly and the change was not undercharged on installation and the difference merely airflow changes do to the stated restricted airflow.

gerry

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