Ice on Coil? Shortcut to melt? Cause?

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Old 06-23-10, 09:01 PM
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Ice on Coil? Shortcut to melt? Cause?

This is just my second summer in this old house, which we bought a year ago, next week.

Up until a few days ago, the central air conditioning system was working great downstairs. In fact, I had to partially close some vents because those rooms would get too cold and I thought it might help get more air upstairs.

For a while, I've been saying that I needed to change the filter, which I thought was an every six month thing, but I now see that it should be closer to every three. And the reason that I actually went down to the basement to find my dirty old filter somewhat folded and being sucked was that suddenly the air conditioner wasn't doing so great.

After a midnight run to Walmart for a new filter, the next day the temperature didn't really improve, it was just better than nothing at all.

Today, I discovered that my outdoor unit wasn't operating. It didn't take me long to discover that it was a tripped breaker, possibly from a power outage that may actually coincide with my air conditioner under-performing. I know that the outdoor unit was working last week when I mowed, so I think maybe the breaker tripped when the power blinked.

Anyway, now the breaker is flipped, the outdoor unit is functioning and I have a new filter, but though things got a little better, they're still not right. So, I partially popped a cover in the basement and I see a radiator-looking thing (evaporative coil?) that has ice over the bottom portion.

1) It's wicked hot. I'm hoping it won't hurt if I use my wife's blow-dryer to speed the melting and 2) Is there a good chance that any of the above is the culprit and the ice combined with the fact that my big copper pipe isn't very cold doesn't necessarily say for certain that I'll need coolant?

Money's very tight right now and I'd rather not call somebody, if it can be avoided.


Thanks in Advance
 
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Old 06-23-10, 09:45 PM
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Lack of refrigerant or lack of airflow across the evaporator coil will cause ice.

I recommend opening your closed vents.
Clean the evaporator coil if it is dirty. (The coil that had ice)

If your suction line (large copper pipe between the outdoor and indoor unit) is not cold and sweating after the condenser outside has run for 15 minutes, you should probably have it serviced..
 
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Old 06-24-10, 12:33 AM
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The ice melted after running just the fan for about an hour, so I flipped it back to A/C and now, when I just checked it after a couple of hours, the ice is back.

I still haven't pulled the full cover off because one of the screws is inconvenient and there's another under a bunch of duct tape. I'm probably going to go down and pull it later because I can't see the backside and at least one photo that I've seen on this site says that there may be two coils.

The refrigerant line is definitely cool and there's a huge difference between it and the smaller "warm" line, but it's not what I would call cold, it's just really cool.

Hopefully cleaning the thing or lettng it melt again will do some good.


BTW: A couple of hours running made the house feel better, but I only got 1 degree.
 

Last edited by TryAgain; 06-24-10 at 12:51 AM.
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Old 06-24-10, 02:54 AM
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Just melting the ice isn't going to fix the problem. I'd say a dirty filter that has buckled so the air can get through is pretty solid evidence. Who knows how long that dirty air has been going straight through to the coil. Clean the coil, then check performance and line temp.
 
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Old 06-24-10, 05:36 AM
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Update

Thanks for the replies.

After my last posting, I pulled the full cover off and adapting some directions that I found in a previous thread, I unscrewed the triangular cover off of the far end and looked inside.

Because of the way the a-frame, coil tent is aligned, I really can only see the back or underside of one coil and though it appears to be slightly dusty and nowhere near as shiny as the front, other than four or five things (bugs?) the size of the ballpoint on a ballpoint pen, I don't know that I'd call it dirty.

Any opinions or recommendations, as to whether dust equals dirt?
And should I still put forth the effort to clean it (because it wouldn't be an easy job)?


Otherwise, I flipped the t-stat back to air, regained my one degree and after running it for about an hour, I took the cover back off and found that the ice was starting to reform on the lower quarter of both the visible front and the visible back. Though it was just starting to reform and has probably melted in the past five minutes.
 
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Old 06-24-10, 08:28 AM
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Any opinions or recommendations, as to whether dust equals dirt?
yes.

And should I still put forth the effort to clean it (because it wouldn't be an easy job)?
Cleaning coils is never fun, easy or cheap. That's why it's easier to change your filters every 3 or 4 weeks. In dusty environments you may need to change your filters every day (such as during construction, remodeling, painting or sanding).

You can do it yourself if you have a good coil cleaning solution and don't bend the aluminum fins.

The best way to clean a coil is to remove the refrigerant, cut the copper lines, remove the entire coil and take it outside.
However, if the coil has a refrigerant leak, this would be a waste of time. In such cases a new coil is in order.

Running the system without fixing the cause may lead to compressor failure.
 
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Old 06-24-10, 08:29 AM
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You went through all these trouble, may be your problem is just low on freon. You said the large pipe is cool, that is not enough, you want it cold and sweaty(condensing water around the pipe). How about your vent air come in to the room, are they blow strong ? and at least 16 degrees lower than your room temperature at that time ? (wish you have a gauge)
 
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Old 06-24-10, 08:45 AM
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Again, thanks for the replies.

I've been mentally prepared for the idea that I'd probably need freon and I'm glad that with the help of this forum (and its little search box), I've been able to eliminate the other possibilities.

Of course, it would've been great if it was something that I could do myself, but the big copper line hasn't gotten "cold" since I first started working on it and though I haven't measured, there's no way that there's a 16-17 degree difference between the return and the outflow. (It feels more like 5)

Now I have the cover loosened, so it'd be easy to show someone and theoretically a guy will be swinging by within the hour with some freon. Throughout the night, I kept cycling between "cool" and "fan" to keep the ice at bay and though I could only gain one degree with "cool", it appears that the wife and kids were able to sleep comfortably.

Of course now it's turned cloudy and there's a pre-rain breeze, so I could possibly open the windows, but that wouldn't have done any good during the night because it was warmer, it would've been a pain to open all of the storms and I would've been left with a humid house.

Hopefully all of this cycling hasn't damaged anything and once the guy gets here to shoot me with freon, I'll be able to take a nap.

Thanks again for all of the replies.
As always, I really appreciate the help.
 
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