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Central Air System Freezing

F

fbrdphreak

Lifer
Hey all,
We've got a problem with the central air in our condo.

There is a closet in the downstairs of our condo and in it is the central air system. I assume that this is the compressor. You can see the radiator fins and the "air handler" is in there blowing air out to the rest of the house.

Well, this morning we got up and it was humid as sh!t. Later that day my gf found that there was a lot of water leaking out of the bottom of it. Turns out it looked as though the condensation pan (which sat right above the air filter) had overflowed.

First we thought the drain tube was clogged so we cleaned it out, but there wasn't enough gunk to actually clog it. It also wasn't the hose going to the sewage system, 'cuz I poured a cup of water down that to make sure it wasn't clogged.

Well, upon closer inspection after running it again the bottom of the compressor(?) turns into a block of ice. The radiator fins get a nice ice build up on them, thus not allowing good airflow.

I did some googling and read that possible causes of this are too little/much freon, high humidity, and some other seemingly oddbal causes.

Does anyone have any suggestions for us? We do have a home warranty and are going to see if this problem would be covered under that, at least the professional diagnosis of it.

Anyone know how much a freon refill costs?

TIA!!
 
Could be low freon, plugged vent dryer, plugged evaporator.

Call the A/C man. Should be less than $100 for a service call + freon.
 
The A/C in my old apartment would do this every so often due to losing Freon. Recharging it is a short term solution, you would need to have the leak in your system found and fixed otherwise you will be in the same situation in a short ammount of time. You may even end up needing to replace the unit if the leak is bad enough.
 
I had the same problem... to de-ice the evaporator just run the central with the fan only... no AC on... you can run heat but that'll make things very uncomfortable.

The AC guy said that my system was low on refrigerant but it seems strange that it would be only 1 year after a brand new unit was installed. On automotive systems, low refrigerant usually doesn't cause icing. I'm not able to quite wrap my head around how low refrigerant can cause icing since I was under the impression that low refrigerant levels meant lack of cooling generally.
 
Originally posted by: KokomoGSTmp
I had the same problem... to de-ice the evaporator just run the central with the fan only... no AC on... you can run heat but that'll make things very uncomfortable.

The AC guy said that my system was low on refrigerant but it seems strange that it would be only 1 year after a brand new unit was installed. On automotive systems, low refrigerant usually doesn't cause icing. I'm not able to quite wrap my head around how low refrigerant can cause icing since I was under the impression that low refrigerant levels meant lack of cooling generally.
Click to expand...
Yeah, that is confusing me as well...... How would low refrigerant cause icing?

Not enough pressure, so it's not phase changing properly or something? Retaining too much cold?

Seems bizarre.
 
Don't see how low freon could make it freeze. Sounds like the compressor isn't cycling off soon enough. If it runs too long, it'll freeze up.
The drain being clogged could help this along, too.
 
This condo is very old (25+ years) and I have no idea how well the AC unit was serviced.

We had a new filter in it, but that thing got soaked so we tossed it for now; will get a new one tomorrow.

Will running the system without a filter cause any problems (in the short term)?

Any ideas/suggestions on how to clean the coils? Where do I find them? 😕
Thanks for all the help guys
 
Found this on Google Answers

"This is usually caused by a lack of refrigerant in the system due to a chronic
leak. The reason that the coils form ice is that when the system is short on
charge part of the coil runs very cold and ice starts to grow. Once the ice
starts to grow it is in insulator and keeps on growing until the coil and the
refrigerant lines are one block of ice.
Click to expand...
 
Originally posted by: Eli
Originally posted by: KokomoGSTmp
I had the same problem... to de-ice the evaporator just run the central with the fan only... no AC on... you can run heat but that'll make things very uncomfortable.

The AC guy said that my system was low on refrigerant but it seems strange that it would be only 1 year after a brand new unit was installed. On automotive systems, low refrigerant usually doesn't cause icing. I'm not able to quite wrap my head around how low refrigerant can cause icing since I was under the impression that low refrigerant levels meant lack of cooling generally.
Click to expand...
Yeah, that is confusing me as well...... How would low refrigerant cause icing?

Not enough pressure, so it's not phase changing properly or something? Retaining too much cold?

Seems bizarre.
Click to expand...

It doesn't(usually). Low air flow causes the suction line temperature to be reduced and you get ice.
 
That would be the evaporator. And yes, low refrigerant will cause this. Lower refrigerant volume will cause lower temperatures, usually below design temperatures, which means that there's not sufficient airflow across the evaporator to prevent icing up.

ZV
 
My house I moved from a couple of months ago did that about 10 years ago. I cleared the A/C drain, melted the ice with a water hose, and it never had another problem.
 
Huh.

I don't get it.

How does a refridgerator work then?

The air comming out of the duct in my fridge is -4ºF, so unless I've completely missed something and fridges work differently than air conditioners, I refuse to believe that an AC isn't supposed to be colder than 40-45ºF. 😛
 
Where are the evaporator coils so I might take a look at them to see if they are dirty?

From what I've seen reading, we have a "split system." We have the large block unit with the fan on it (is THIS the compressor?) outside and inside we have the actual air distribution and radiator fins.
 
Originally posted by: fbrdphreak
Where are the evaporator coils so I might take a look at them to see if they are dirty?

From what I've seen reading, we have a "split system." We have the large block unit with the fan on it (is THIS the compressor?) outside and inside we have the actual air distribution and radiator fins.
Click to expand...

Inside (air handler). Use a wire brush and some 409 to clean the fins..........
 
Also, for the past couple weeks we had some of our downstairs air vents closed to direct more air upstairs. The system never blew air very well (replaced filter when we moved in 2 months ago) and so we wanted more airflow upstairs. Would this have caused any problem? I thought I read something about blocked air outlets or something....
 
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