Home AC not cooling well...

[Anonymous]

My AC was struggling to stay at 78 degrees this weekend while the temperature outside was 88. In fact, it seemed to run all day without stopping because it could not get the house to 78. It was hanging around 79.

I noticed a few things. First, the air pressure coming out of the vents seemed low. I recall being able to hear the air at times in the past. Now I have to put my hand over the vent to see if the air is on. Second, the air coming out does not seem that cold. Third, the secondary drip pan, under the unit in the attic had a lot of water in it (not sure if that is meaningful). Fourth, I openened a vent in my crawl space and the air under the house felt very cold.

Everything I have read so far suggests that I need a coolant recharge. And that I probably have a leak. Does that sound right? If so, how do I go about finding the leak myself? I prefer to try to cut down on the cost of the repair.

The other thought is that I might have leaky duct work under the house, hence the cool air there.

Thoughts? Opinions? How much does a recharge cost these days? I live in the Raliegh NC area.

Thanks!

[louie]

Check the air handler filter first. Changing that may solve your problem, since it sounds like your fan isn't moving much air. If that doesn't help, then you're only out the cost of a filter (which is something you should be changing regularly anyway).

[Pete C.]

Not sure where you conclude you need a coolant recharge, everything you describe points to a damaged duct in your crawl space dumping the cooled air into that space. Suit up and go in and inspect the ductwork for damage. Could be as simple as a broken duct clamp.

Pete C.

[Anonymous]

OK, I assume avg Joe here. You don't meant the intake filters in my house that I replace every 3 months do you?

J

[Anonymous]

Is there something better to patch with than duct tape? That sounds stupid, even as I type it.

J

[Pete C.]

The proper duct tape is the metal foil variety. The "common" duct tape isn't for ducts.

Pete C.

[louie]

Yes, that's the one. If that's not your problem, I think PeteC may have a good suggestion in his reply below. Even if the filter does help it probably wouldn't be a bad idea to crawl under and look for leaks and to insulate the ducts. If cold air is getting under your house instead of inside where you want it, you're wasting money.

[hvactech2]

There are quite a few other problems that could cause the symptoms you have. The only way to find out what the actual problem is is to call a local company to look at it. as for finding leaks, there are electronic leak detectors for that and they are quite expensive.

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[Anonymous]

Update:

I have crawled around in my crawl space inspecting all of the AC duct work and I can't see a single problem. Some of my flooring insulation has fallen down (an easy enough repair and unrelated), but everything looks good so far.

I plan on calling a _local_ AC repair company eventually, I am jsut gathering recommendations now. Also, I just want to be prepared. If I can find a problem before I have them come, then that works better for me.

One other note. I had a national company check my system when this first happened (end of last summmer) and they said everything looked good. Mistake 1: I believed them. Mistake 2: I didn't call them on it when I discovered it.

Any suggestions on what to check next?

J

[Kathy]

the

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change you filter now

[Grumman-581]

Take a digitial thermometer with an external probe (like one of the indoor/outdoor thermometers), put the probe inside the vent and measure the temperature... Measure the temperature at the warm air exchange (where the filter is) also... There should be a minimum of 12-16 degreees F difference between the temperatures... The more difference, the quicker the house will cool... My current house has a 20 degree F difference and it is able to keep the temperature at 73F rather easily even here in Hot Ass Houston... If your temperature difference is sufficient, the problem is not with a freon issue and also probably not a compressor issue... From there, I would start looking at the possibility of it being an air handling issue... Maybe insufficient air being sent throught the system (filter clogged, fan bearings wearing out, etc)...

[Pete C.]

Did you have the fan running when you inspected? A duct leak could be hidden under duct insulation and not be apparent without the system in operation.

You indicate low air flow from the vents which tends to indicate either a leak, a restriction or a blower problem. You've not found a leak so you should check the condition of the blower in the air handler and look for any possible restrictions in the system. In the case of a restriction it would likely be near the air handler since it if was on a particular duct you would likely have high air flow to other ducts.

Since you indicated there was water in the secondary drip pan, that would tend to indicate the main condensate drain might be clogged though that is likely not the source of the problem unless perhaps the blower motor is straining trying to spin the blower in water.

The water in the pan also implies that the refrigeration is working and that an air supply is getting to the A coil in the air handler. If the refrigeration was not working the water would not be getting condensed and if there was an air restriction on the intake side there wouldn't be a supply of moist air to keep condensing water out of.

Best thing to do is to open the air handler (should just be a couple screws) and inspect. A squirrel cage blower trying to run partly submerged in condensate from a plugged drain certainly won't be able to move much air. A piece of internal duct insulation in the air handler could have come loose and clogged the output. Certainly should be relatively easy to inspect.

If the air handler has a belt for the blower it's possible it could have broken and the air handler is essentially moving no air. You might have felt a slight flow just from convection.

Pete C.

[MC]

A couple of things to check.

Filter as mentioned. Also if duct work is in crawl space, could have come loose if seemed cold, would also be pulling more mist air from outside instead of recyling and therfore could be the extra water in the drip pan ?

Also check promary pan for the A-coils, mine rusted out last year and had to fabricate another, got a lot of water in the secondary pan, noticed after blew out my fan motor with all the water leaking down through the furnace (furnace checked out fine)

also see if outside condensor coils and unit needs cleaning, may be dirty no allowing enough air flow to remove all the heat.

[Joey]

I stongly agree that you should open the air handler and physically look at the cage motor, belt, and make sure it's blowing properly. I don't think your freon level is low either. Maybe just down the line in your duct work possible a diverter has shut off ?? If the air is flowing properly at the unit then go down line past the first split and cut a small say four inch square opening that you can fold back. Check the air here. If it's OK bend the metal back and tape it up. Then keep checking down the line.

J

Grumman-581 wrote:

[CJT]

My guess is your ducts are leaking like crazy, probably near the evaporator where the pressure is highest.

[Ralph Mowery]

If the air flow is low, you can have several problems. Check the air filter to see how dirty it is. Look where the lines comming from the outside unit go into the air handler. If there is ice then you may need the unit recharged with the refrigerant (freon) . Seems strange, but low refrigerant will cause an ice condition for a while. Also see if it feels cold on the larger line. YOu may also have a leak in the duct work. Check to see if the fan in the air handler is turning up to speed.

[Bubba]

Suprising! Almost 12 posts and no one "hit" it yet. I think you need to be looking for ice and frost and you will find that it is where it should not be. Hint: You wont be able to fix it yourself and WHY you would call a national company is beyond me. Many locals that can do it. Check around, get references and DONT look for the cheapest chump to fix it. Bubba

[mm]

If the air pressure is low, your neighbor may have tapped into your AC. Look for air ducts between your house and his.

They may be buried, so look for signs of recently dug trenches. Such as damaged grass, unlevel soil.

Possibly your children are stockpiling cold air there, because they heard that the price of oil will be going up. This is a much talked about remedy on teen chat lines.

[udarrell]

Check to see if the evaporator coil is iced over. Check the blower to see if it is operating in condensate water, as stated! That will burn out the motor, so pull it and dump the water before operating the unit again. When operating with normal airflow and a clean blower wheel and evaporator and 400-cfm per ton (12,000-btuh) the temperature drop should be around 16 to 20-F. A heavy humidity load will cause a less or lower temp difference/drop. A graph on a couple of my web site pages illustrates the latent load effects.

Second Graph-Pages loading ultra slow, wait if problem with Server!

If the evaporator ices over after running it a while with normal airflow until then, it could be a refrigerant problem. Run the furnace for a short while and then shut everything down until the A/C tech comes.

Darrell

[ds549]

your cooling coil may be clogged with dirt... the blower gets dirt on em that cuts flow also..best to clean the outside and inside coils,,and fan blower...if it still wont cool after that, get a tech to look at it...