Hello all, I am hopng someone can help. My central air system works fine for a few hours, but then after (approx 8 hours or so) it is no longer blowing air out of the vents in the ceiling. The system is running as it should, compressor fan outside is still spinning and it sounds like it should be working, but no air is coming out, although the vent does still seem cold, no air is coming out of it. The only way to get it to work again is to turn the system off for about 2 hours, then when I turn it back on it is working normally. Could something be freezing up? Has anyone heard or seen this before, anything I can look at?
Thanks in advance...
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U
udarrell
It might be that the evaporator coil is freezing over, or the fan motor, for various reasons, is getting too hot. Stop operating the unit when the blower is NOT delivering adequate airflow or you will ruin the compressor,.
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- udarrell
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Reality Is Not An Easy Thing To Be Confronted With, or to Accept!
M
mm
Yes, I think, but that would be an effect of the inside fan not blowing, not a cause of it. No amount of freezing would stop air from coming out of the vents if the fan were running. (although don't depend on me. You can and should verify this by going to the furance and listening to tell if the fan is running or not.)
Not me, but...
Anything can happen, and there is always something to look at. :)
How about turning your thermostat fan co;ntrol to On instead of Auto, and see if the fan runs then? If it does, then there's somewthing wrong with the auto part. If it doesn't, there's something wrong with the fan or the fan circuit.
How much are you willing to do in order to fix it?
If it's the auto part, you could scrape by by leaving the fan on On, not auto, but I would hate that because I hate the noise of the fan, and it wastes electricity imo.
Assuming it's the fan and not the auto, I guess a simple thing would be, when the fan isn't working during that two hour period you describe, especially the earliest part of it, since you don't know exactly when it starts working again, to find the two wires from teh control unit to the indoor fan and check for continuity through the fan and the wires to it. You probably have to disconnect one of the two wires to do this. Have we reached your limit or do you want more?
V
ValveJob
The inside coil is freezing over and caked with ice preventing any/much air from flowing thru it. It is caused by the slow leak of freon in the system. The cure is to add a small can or two of R-22 until the temperature of that large insulated suction line going to the outside unit is 'beer can cold'. Or about 50 to 55 degrees.
M
Meat Plow
You need to get an air tech out there and check it out. You're probably a little low on freon as it doesn't take much to freeze the inside coil when it's hot and humid.
M
mm
Or if the other two are right, I could be wrong!
M
Meat Plow
I've seen plenty of A coils freeze like a block of ice. A small amount of air does leak around the coil but that's it.
M
mm
There is no reason to bring gender into this.
Thanks. I guess I was wrong in those two lines of mine at the top, and I presume the OP is still reading.
:-)
M
Meat Plow
bwahahah
Yeh but you're right so many more times....
R
Richard J Kinch
Yes, paradoxically caused by a refrigerant leak and subsequent low refrigerant charge.
Another possibility is squirrel-cage fan blade out of balance, which slows the fan speed and overheats the motor. They get unbalanced from corrosion, especially if the fan is after the evaporator.
S
Stormin Mormon
Actually, yes, I've seen this happen. Freezing indoor coil will block air flow.
S
Stormin Mormon
Yes, it's possible. Or, the outdoor unit may be dirty, and overheating.
S
Stormin Mormon
Or, the outdoor unit is overheating. At which point the solution is to clean the outdoor unit's coils.
S
Stormin Mormon
Male coils don't blow unless there is something terribly wrong.
L
longshot
I just had my rental house's serviced for the same problem, seems the coils were covered in dog hair & air wasn't getting through thus allowing the coils to freeze over fairly quickly
M
Meat Plow
That's another possibility that I've seen back in my hvac days in the
70's-80's. Same for the condensing unit outside being dirty/obstructed and not being able to produce enough refrigerant.
J
jgiannone
Great thanks for all of the replies. I will definitely check out the inside coil and see if it si freezing over, this makes the most sense.
I did have a tech over, but when he came over it was working properly. he check ed the levels of freon and a couple of other things and said everything looked fine.
R
Ralph Mowery
I had one that did the same thin, almost no air as the coil froze. It was low on the refrigerant.
Funny how low refrigerant causes the coils to freeze but that is the way it works.
L
Lee
Exact same symptons that my daughter had with her A/C last year.I was there when the Tech arrived. He checked it out and the only thing he found was the system was low on Freon that was causing it to freeze up and blocking air flow. Added freon and it worked fine after. Still working 1 year later! Hope this helps!
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