HVAC folks--AC help

Last night I noticed that the AC wasn't really keeping the house cool. Or it was keeping it cool, but not cooling it anywhere near where it should have been.

Well, I open up the panel in the basement and there is ice on the coils(?). So, I turn off the AC, turn on the fan only, and let it (fan) run for about 10 hours. Then first thing this morning, I went out and bought and put in a new filter (old one was filthy). The house was about 79 when we left the house at 9:45; at 6 when I got home it was 80. I thought that was pretty good considering it's about 92 outside. But the ac is blowing cool, not cold

I opened up the panel again, and there was still ice. I'm not sure if this was new, or left over from last night and I didn't give it enough time to defrost.

So, in everyone's professional opinion, what should I do? I think I'm going to go and take a hair dryer to the coils tonight, and see if it improves it. Any other ideas? Obviously we need to have it serviced, but that may not be possible in the next 3 days--no one to be there with the service guys.

We're in a time crunch with this too. Thursday, we are gone for 4 days. The house needs to be cooled by Thursday, because the dogs will be there still (dog watchers are coming).

Sounds like you need to open up the air handler and clean the A coil?

TRoglodyte wrote: Sounds like you need to open up the air handler and clean the A coil?

How do I do that? Clean it I mean

If it's not an airflow issue (dirty evaporator coil, dirty filters, bad blower, etc.) the system being undercharged (i.e. some leaked out) will make the evaporator run too cold and ice up.

It's low on freon.

Get it recharged and see how long it lasts. If its a slow leak it might last a while otherwise it might be time for a new unit depending on how old it is.

A good rule of thumb is ~$1k/ton for a new unit.

Low refrigerant.

Why do we think it's low on freon and not bad air flow? Like I said, the filter I replaced was absolutely filthy, and I don't know that all the ice melted last night (now that I think of it, I only gave it about 7 hours instead of the 10 I originally stated)

With the compressor off, and the fan running, all the ice should melt in a couple of hours. 7 hours should be more than long enough.

99.5% of the time, freezing coils is low refrigerant.

See if the lines between the outside unit and the air handler are also freezing. That is a sure sign of low refrigerant.

Frozen coils = low on freon.

I learned that after living in Florida for 25 years.

Toyman01 wrote: With the compressor off, and the fan running, all the ice should melt in a couple of hours. 7 hours should be more than long enough. 99.5% of the time, freezing coils is low refrigerant. See if the lines between the outside unit and the air handler are also freezing. That is a sure sign of low refrigerant.

No frozen lines outside.

And no freezing lines that I can find other than the coils inside.

So I mentioned that "there was still ice". That was at 6pm. Now, at 8:30 I opened it again and the ice that I saw was melting! I had turned off the AC about 3 minutes prior to that.

So ice melts inside a 90 degree house?

(Almost every homeowner get to experience this at some point. Especially those who don't change filters)

Sorry you're going through this. Sounds like your refrigerant leaked out.

OHSCrifle wrote: So ice melts inside a 90 degree house? (Almost every homeowner get to experience this at some point. Especially those who don't change filters) Sorry you're going through this. Sounds like your refrigerant leaked out.

Looks like it did. Basement is only 73 though

Seems odd. No ice on any lines outside or any lines going outside. No ice has formed since my last post, but it's still blowing cool not cold.

Gotta get someone out tomorrow or else buy a couple window units for the dogs for the weekend.

I would clean the coils and check air flow before I pay someone to berk...err tell me I need a new system.

In reply to mtn:

Mine was dirty from pets, open up the unit and clean the crud off it.

mtn wrote: Why do we think it's low on freon and not bad air flow?

Because every single time mine has frozen up, it has been low refrigerant. Each time related to a leaking coil in the air handler.

mtn wrote: Why do we think it's low on freon and not bad air flow? Like I said, the filter I replaced was absolutely filthy, and I don't know that all the ice melted last night (now that I think of it, I only gave it about 7 hours instead of the 10 I originally stated)

Your thinking here is correct.

There is no reason to assume it is low on refrigerant when you have already identified a significant airflow problem. Either could be the problem.

Clean it up and see what happens.

It is NOT true that frozen lines= low refrigerant. That is, however what an AC repairman will say (because they can charge more for the service)

....however, since you have now cleaned it and see no difference, yeah, you might need a refrigerant recharge.

(I'm kind slow posting)

Yeah, I'm trying to get someone to come out today. We will see--if they can get here today or tomorrow, we will have it fixed. If not, I'm throwing a couple window units in and letting next-week-mtn deal with it.

In reply to SVreX:

For your reading pleasure. It happens more often than you think.

When the refrigerant in the system is low, the pressure; and therefore temperature, of the refrigerant will also be lower. In a normal system, the temperature of the refrigerant at the beginning of the evaporator will be right around the freezing temperature of water (32°F). As the indoor air moves over the cool coils, the moisture in the air will condense on the coils. This condensation will drip harmlessly off the coils, and into the condensate drain.

It should also be noted. Once the refrigerant level drops too low, the system stops working. So this problem only occurs in a "sweet spot", where the refrigerant is low, but not too low.

Mine was doing that, turned out to be low on freon. Tried a new filter and cleaning the coils before calling a professional. Depending on the age of the unit, just adding freon may be exspensive.

In reply to Toyman01:

I did t say it doesn't happen. It happens all the time.

I said the people that are saying it can't be the airflow are wrong.

SVreX wrote: In reply to Toyman01: I did t say it doesn't happen. It happens all the time. I said the people that are saying it can't be the airflow are wrong.

I don't think anyone said that it can't be the airflow ... most people said it was low on freon though ...

We freeze up units regularly. Like once every couple of weeks.

For us, it is almost always the airflow. Mostly because we are actually the ones making the dust.

Majority of times for most people, probably the refrigerant. But that doesn't change the fact that basic diagnostics say check the airflow first.