# HVAC not blowing out of vents



## JJboy (Oct 12, 2010)

1- Check if Blower Fan is running. If it running ok....turn off AC and leave only Fan on.....A-coil is frozen.
2- Check all return filters are clean.
3- Check for small leak.


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## autx790 (Aug 30, 2009)

Hey JJ boy, thaks for the tips. The filter is brand new. I've had the blower running for about an hour. How long should i let it sit before turning the AC back on? If i turn it on and it freezes again, does that mean it's probably low on refridgerant? I dont see a leak, but if it's low i'm guess there would have to be one, right?


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## JJboy (Oct 12, 2010)

Yes, leave fan on more time......Next time you turn on the AC check if is getting good air flow at the supply registers but warm air.....The refrigerant is low

The best way to check for small leak is pressurise with nitrogen at 150PSI and leave all night under pressure


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## beenthere (Oct 11, 2008)

I usually tell people 3 to 4 hours with just the fan running to thaw a coil.


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## bbo (Feb 28, 2010)

leave the fan on overnight.

there should also be a drain line for the AC unit, make sure this is not plugged. if it is, it'll just freeze right back up when you turn the AC on.

unless you have the means to check the refrigerant, ( ie pull it out and weigh it) you'll likely not be able to diagnose low refrigerant.


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## biggles (Jan 1, 2008)

did you leave it on all night and did it get a little cool outside overnight?the ice always starts at the air handler then works it way out into the condenser and covers the compressor.if have ice forming on that insulated line coming out of the air handler the coil is icing up and air is being retricted and gets as you feel nothing out of the vents...so the filter is good supply fan squirrel fin/rounds are clean


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## autx790 (Aug 30, 2009)

Thanks guys. I left the fan running for 3-4 hours and now i try it again. I get a tiny bit of cold air coming out of the vents closest to the unit, but at the front of the house where the return grill is, there is pretty much no air still. The return air doesn't appear to be sucking near what it used to. I hear/feal nothing. I guess i'll leave the fan running over night and then give the AC people a call in the morning.

On the unit outside there is a opening going out of the unit and it is not obstructed so water drains out.


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## beenthere (Oct 11, 2008)

Could be a dirty indoor coil, or bad/weak capacitor.


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## autx790 (Aug 30, 2009)

actually, in the time it took me to write that post, the unit is completely froze over again. Everything was covered in ice.


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## autx790 (Aug 30, 2009)

The AC tech just left and it turns out, i'm not low on coolant, and the evaporator coil is clean. So his guess is there is something stopping up the return duct, but I just dont see what could do that (it's a big trunk). They're going to have someone else come out to take a look at the duct work.


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## Doc Holliday (Mar 12, 2011)

Completely ridiculous they didn't take care of this right then and there, especially for something as easy as opening up a trunk line.

Insulation has been known to drop from the inside of air handlers and stick onto the coil or from the coil itself.


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## autx790 (Aug 30, 2009)

Hey Doc, what's ridiculous is him charging me $89 to tell me someone else will have to figure it out. On my unit it's all together outside and you have to take the top off to get to the evaporator coils. There wasn't insulation or anything blocking the coils, but it was hanging a little in the blower box and looked to be a little damp. he just pulled it out and through it out. He said it wouldn't hurt anything not replacing it. I'm guessing however that the insulation was there for a reason and had a foil facing for a reason too, and now there is a little insulation left but the foil is gone. 

I will say whatever the problem, it's completely blocking. If flow rate was a measured scale from 0-100, then before it freezes over (which takes 5 min or less) im at about 7.


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## Doc Holliday (Mar 12, 2011)

I was just going to say I hope you didn't pay him, but at the last second deleted it from my previous post. Too late now but you should've said you'll pay once the other guy comes out and at the very lest finds the problem.

You have a pckage unit? It could be a collapsed trunk somewhere or simply a hole in the trunk line as well as or either insulation stuck somewhere BUT if it was insulation than 99% sure it would have been sucked up and into the evaporator which all you need to do is remove a few panels to get to on a package unit.


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## autx790 (Aug 30, 2009)

Well that was the charge, but I'm not having to pay till they get it resolved. 

On my unit the whole top comes up and that's how you get to the evaporator. It's an old (2007) Goodman. Though it looks a lot older. I'm not sure how a truck would collapse cause it was working just fine saturday morning, and then just stopped. I'm hoping some part of the house didn't drop down on it. But hopefully i'd notice that  There is no air coming out of the registers, but if you open the side panel of the unit where the blower is, then you will get air flow. At least that's what he said...I hadn't tried that yesterday.


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## Doc Holliday (Mar 12, 2011)

I'm a bit confused. Can you take a pic of the system and post it here? And do have any toOls at all such as a drill with 1/4" and 5/16" drill bits or even simply nut drivers of those sizes?


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## autx790 (Aug 30, 2009)

I've attached an old picture that I have....I'm not able to take a new one right now. The unit you can barely see infront of the closer one is for upstairs. The handler is in the attic. On the unit for downstairs, the top comes off to give you access to the evaporator coils. On the other side of them, where the blower is, that front panel (the one facing the camera) comes off. You can access the blower and circuit boards there. Does that help?


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## Doc Holliday (Mar 12, 2011)

Do you have access to under the house and a flashlight? I'd crawl under there and take a look at your ducts. You may have a hole in either of the lines but I'm thinking the supply line, meaning you are losing air under the house. And a big hole at that, seals came apart. 


From here, with everything working and with the tech putting his gauges onto the system and verifying proper refrigerant levels with the unit running (which he did, right?) than that's all it can be at this point or at least from my viewpoint. If you had a restriction such as a blocked return the pressures would be noticeabely different, far off. And the evaporator coil would freeze. The system, if left off overnight, would blow regular and then within a few minutes to an hour it would begin to throttle back until you had no air flow at all. 

You are saying there is nothing from the get go.


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## Doc Holliday (Mar 12, 2011)

And be careful under there. Possums and squirrels and mice and even snakes will borrow into your duct work. Some of the bigger ones will rip it apart just to nest in there. 

I had three kittens in my wall, fell through from the attic. The mother cat had them up in there, tore through my soffit to get in.


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## autx790 (Aug 30, 2009)

yeah, that's a good point. The tech said everything looked good at the return under the house and as far back as he could see. I may crawl under there later after work. I've been redoing the whole house and spent maybe hours under there. but never noticed any issues with the duct work. The coolant levels were good and when he popped the cover off the top he did say the unit was starving for air. Something like that. He felt like it was more of an obstruction than a hole somewhere.


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## Doc Holliday (Mar 12, 2011)

If you don't find anything wrong with the duct work and this other tech can't either, than ask about checking amperage draw of the blower motor and the uf rating of the capacitor. It could be spinning but not was fast/hard as it should be but again, the refrigerant pressures would be off if that were the case and the coil would freeze up. 

And if you do find an animal in your duct work, could you take a few pics and post them here. If you make it out alive, that is. :thumbup:

NO PICTURES OF SNAKES, I HATE SNAKES!!


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## autx790 (Aug 30, 2009)

Gonna go take a look. I'll tell you, we've had plenty of animals in the attic/walls of this house but mostly just rats, squirrels and bats. I put hardware cloth up underneath the house and that's stopped most of the 4 legged animals getting in there.


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## beenthere (Oct 11, 2008)

Remove panel to blower motor. Either turn the system on, or turn the fan switch to on and see if air comes out your registers. If so, then its not a supply duct problem.


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## autx790 (Aug 30, 2009)

Hey beenthere, 

The tech did that. He left the panel cover pryed open and air would then come out of the registers. So we're thinking it's something with the return ducts. From what I could see under the house yesterday, i didn't see anything completely obvious...of course I wasn't able to inspect the full length of the return. Sorry doc, no animals.


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## beenthere (Oct 11, 2008)

Is your return flex duct?


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## autx790 (Aug 30, 2009)

yes. 14" i believe (or bigger). And it's sitting on the ground.


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## beenthere (Oct 11, 2008)

Inner lining may have separated, and be restricting air flow.


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## autx790 (Aug 30, 2009)

Indeed. The inner liner has come loose and was stopping air flow. They replaced a good length of the return duct and it's working fine now. There is one spot they couldn't really get to, so lets hope that section doesnt fail down the road. Thanks for the help guys!


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