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Central Air Conditioner VERY WEAK At Blowing

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  • Aug 6th, 2010 5:10 am
Sr. Member
Apr 29, 2010
677 posts

Central Air Conditioner VERY WEAK At Blowing

I am trying to figure out WHY my central air conditioner isn't blowing hard enough. It is blowing cold just the output is very weak; a very faint breeze.

From outside this is what the A/C unit looks like:

Image Image Image Image Image

From inside (the basement) here are shots of my Furnace and Duct. There is nothing else apart of the house I could imagine related to the A/C from outside:

Image Image Image Image

I pulled out the ONLY filter i could find and it seemed clean enough and even when the filter is removed running the A/C it still weak.

I'm not sure how the A/C unit relates to the inside Furnace. Perhaps it only uses the duct and completely ignores the the furnace (the wiring).

Any ideas why the A/C is running weak? Is there another filter somewhere that could be clogging things? For the record running the furnace is 100% ok. I recall the furnace being gas forced air.

8 replies
Deal Expert
User avatar
Jul 30, 2007
16009 posts
Wow. Your a/c must be really old. probably 20+ years ?

Maybe your duct needs to be cleaned ?
Sr. Member
Apr 29, 2010
677 posts
Well the house is like 1993 and so yes the A/C must be about that old.

The furnace worked fine during winter so if the A/C is using the same duct would that mean there is no clogging? I really no nothing about this stuff so...

If you can give me pointers I'll check things out. As far as i know i will look into the vent grates for any large foreign objects.
Deal Expert
User avatar
May 10, 2005
25010 posts
The air conditioner just cools a coil in the furnace duct.
The furnace blower motor is in fact what "blows" the air around.
Your filter looks filthy and plugged up so that could have accounted for poor airflow. The fact you pulled it out and it did not improve the airflow tells me something else is wrong.
You can try and clean the blower motor. Disconnect the electricity from the furnace before you start.
http://home.howstuffworks.com/home-impr ... urnace.htm
My personal suggestion is to get a service company to come in and do an inspection and cleaning of your furnace. There are many around so call around and get prices. Generally it would cost in the neighborhood of $150. There are a couple good furnace and air conditioner threads on this forum, have a look there.
Sep 28, 2009
333 posts
1 upvote
Maybe if you bought it flowers every once in a while it would get better at blowing.
Deal Addict
User avatar
Dec 17, 2008
1266 posts
There are few possibilities, but let’s start with the basics. Dirty filter causes low airflow and low airflow causes coil freeze up. Turn the A/C off for a few hrs and replace that dirty filter, then turn it back on and see if the air flow is back to normal.
Nov 14, 2006
454 posts
Looks like an incredibly well maintained machine, I can't imagine that it doesn't work!
Deal Addict
Mar 21, 2006
4164 posts
Burlington, Ontario
That appears to be a washable filter.. Have you ever ever cleaned it? It doesn't look like it. I'd suggest just replace the filter. I'd also suggest having someone come out and service the entire thing because it doesn't look like it has been maintained or cleaned at all.
Audio - Video - Data - Security - This is what I do
User avatar
Dec 6, 2009
232 posts
here's some possible causes why your getting poor airflow..

- your A/C is very old.. looks like it hasn't been looked at in years
- your not cleaning your filter often enough - washable filters are junk.. if your gonna cheap out on the furnace filters go with disposables.. change 'em every 3 months, you want to find a good balance between low air flow restriction & filter strength.
- your furnace is just as old as the A/C, has a weak fan motor
- it's extremely hot outside - your A/C will run allday and probably won't reach the set temperature.. this is normal
- the refrigerant pressures are low.. it's quite normal for older A/C's to develop leaks in the lines connecting the condensing fan outside to the indoor unit - would need to be checked by a certified HVAC mechanic

what it really comes down to is proper maintenance, it's like your car they need to be cleaned and maintained if you want them to last.

the essentials when in comes to maintaining your HVAC system are
Air Ducts - Sears is the best.. by far.. they are expensive.. but hey,you think Mike Holmes is cheap! you get what you pay for.. especially in duct cleaning.
Furnace - Tons of contractors who offer this service.. usually ranging from $150.00 - 200.00 for quality services
A-Coil - sits directly above the furnace.. if you have A/C

These 3 are the essentials when it comes to maintenance.. everything else you have down there is an upgrade.
HRV, HEPA filter, Air Cleaners, Humidifiers.. ect

They are all connected.. when your fan motor starts.. it pushes air upwards through the furnace.. then through the coil..then through the airducts which bring it ot the registers in your bedroom.. which gets sucked back into the system...via that big wide vent on the wall.. AKA cold air returns.

Clean equipment runs more efficiently.. saves in energy costs.. has less chance of breaking down.. and gives you a cleaner indoor enviroment.

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