It's ALWAYS something at my house... my cheapo builder should be shot...

Anyways...

My AC isn't keeping up with the warmth whereas my neighbor, two houses down who has the exact same unit/floor plan/square footage/etc, is able to keep their house at a cool 68. Mine is struggling to make it back to 75 overnight when the external ambient is 70 (maximum that it's been IN the house was 86... yes, 86).

I've had the AC folks out. They gave it a squirt of freon (yes, I know this means I likely have a small leak) and gave it a clean bill of health. They checked the temperature at the external unit, freon pressures, and a few other things but, one thing they haven't done is go into the attic and really give the internal unit a good frisking...

My thought is that the internal unit - despite having a strong blower - isn't able to cool properly because the unit is likely very dirty. I know for a fact that when the green-carded crew came in and did the dry wall, the AC was running full-tilt and I'm nearly positive that NO cleaning was ever done to the duct work or the unit. Additionally, the install a$$clowns didn't even secure one of the return air ducts so, the blown in insulation from the house got sucked up in to the unit the first winter we were in causing an AWFUL motor noise. The HVAC guy that came out that trip (a warranty trip) pulled out SEVERAL handfuls of blown in insulation that had been sucked up. My hunch is that the unit (which is sealed with lots of metallic temperature tape) is full of goop (blown-in insulation, dust from drywall, etc) and is choking out the efficiency. After mentioning this to the AC guy, he said that he didn't think so because of the pressures that he was seeing on his gages and the fact that it was blowing adequate air...

Okay... what do you guys think?

I'm entrepreneurial enough to cut the tape, remove the sheet metal screws and pop the thing off of there in an effort to 'see' if it's gunked up but, I want to make sure I'm not going to screw something up. I know these things are pretty darn simplistic and I know it'll cost me a fortune to have someone come over and do this - even though I'm told it's not needed by at least one AC guy (who may have been lazy and didn't want to do it because it does look like it'll be a PITA)...

Should I rip in and attempt to clean it up? Can one buy that special tape at my local Lowes or HD?

Also, for the record, the AC guy put in about a half-pound of R-22. The filters for the house are changed REGULARLY. Return-air duct work is free and clear of obstructions.

 

i sent you a pm

 

check those filters. i work on boilers/ furnaces and every once in awhile i run into a unit that isnt sized right for the building.. but you said your neighbor has the same unit right?? is a belt driven fan?? check the tension. just like a vehicle loose belt causes problems.

 

Use thermometers like we use in ductwork on cars. Hang it in the individual vents. The outcoming temp should be in the 50's' Check the velocity of the individual vents. If there is any flex duct check all the joints. Check the the condensate line out side just to see if it is draining. Alsck of moister would mean either no humidity in the house or a frozen evaperator coil.
Does you neighbor have more shade trees than you do. Also the direction your windows face make a big difference.
If there are obstructions in the ducts get the shop vac out and clean them out.

If the inside fan hasn't been inspected, check it out. A couple of good size leaves in that fan can cause major slowdown of airflow.

 

That is something I'll check on... it is fan driven.

More specifically, should I crack the tape on the unit, unscrew the sheet metal and get in the unit in the attic (the main air handling unit/condensor). I really think that it's dirty but, I don't want to crack that booger open and get stuck holding the pot on something that I can't remedy...

I'm willing to pay to have someone do this (or, at least, check on it) but, I think it's probably something that I can do (save the coin and go ahead and get it done because the HVAC backup is over a week around here right now)

 

Thanks, Tumba.

Actually, the neighbor's house gets MORE direct sunlight than mine and we're both on nearly an identical angle with the sun - which makes it even more problematic for me.

I got up there yesterday and fished around all of the flex duct work. From the looks of things, everything is zip-tied in and isn't leaking air - or, at a minimum, VERY little. Additionally, all of the ducts were pretty well buried in the blown-in insulation.

I'm going to cut the tape, unscrew the sheet metal screws, and see what I can see around the evaporator coils. I'm getting condensate falling out of the unit so, I don't think it's freezing up - I just think it's dirty as all hell in there (insulation & drywall dust) - or, at least I hope it is.

Thanks again for the help, guys.

-RP-

 

ive had to go back and fix the installers mistakes. they just throw it in flip the switch and run out the door. you can buy a condenser brush at home depot etc... i just use a old paint brush and one of those small car vacs. my knowledge is limited on the a/c side of things.

 

They do sell coil cleaner at Lowes and Home Depot, at least here in Florida. If you find the coil is dirty, the BEST way is to have a pro come in and disconnect the coil from the unit and remove it. This is the ONLY way you can fully clean the front and back side of the coil. The coil cleaner you can buy is like a foam, you spray it on the coil while it is inside the unit, and while it foams it brings the dirt and gunk out to the front side. Then, i usually take a stiff brush and water bottle and scrub the coil up and down, starting at the top, then rinse with water. Make sure the disconnect is thrown before starting work. I had to do this to my g/f's air handler in her apartment. Also, if you are feeling really frisky, you can pull the fan out. Willing to bet you have a ton of build-up of dirt on the fan which can lower the amount of airflow from the unit.

Do you know what your leaving air temp. is from the unit?

 

Hey Rock, I'll trade your slightly working system for my no system. Deal?

 

Thanks, Luke. I'll check for the cleaner stuff tonight when I buy the tape to reseal it. I bet it's gunked up too.

Not sure on temperatures at the ducts versus from the system. I'll attempt to collect some measurements.

TPC11 - no deal, bud. LOL! Sorry.

-RP-

 

RockPick - you can pick up the foil back duct tape at Lowes or Home Depot. I bought a roll recently at Lowes to seal a dryer vent connection. Stuff is STICKY.

 

Hey RP,

Can't help with the AC (how's that for an opener), but I thought I'd toss my 2 cents in. Make sure that what ever insulation you step on when you're in the attic is either "fluffed" back up or you put more over it. As I'm sure you probably already know, compacting the blown in insulation can affect the insulation's effectiveness and this could cause condensation or problems on the roof with snow in the winter. Not sure how much you guys get down there, but I thought I'd just bring it up as a CYA.

Duke

 

I cleaned out the coils as best as I could this evening. I accessed them by going in through the main 'output' duct hole and then resealing it after entry. I utlized a spray bottle with DI water and flushed everything toward the drain. To be 100% honest, I didn't really notice much 'goop' coming out of there so, I'm worried that it may have all be a waste of time...

I wish I knew what was wrong with this damn system...

It's 67 outside and I bet the unit will run ALL NIGHT to get to 71 by morning. It just doesn't make sense that a unit of like in kind two doors down can accomplish SOOO much more than mine with the same age, floor plan and square footage. NO sense...

 

RP,

I just read some FAQs and help tips on central air units on at least 10 different sites. The commone suggestions for issues similar to yours were

1. Is the air coming out of the unit around 20* (+/- 2*) cooler than the air going in? If not, the unit is not balanced properly.

2. Capacitor needs replacement.

3. Condensor needs replacement.


No idea if your problem is any of the above, but just thought I'd rattle off the common trends I saw. Hope you find the fix. I know it's easy to say when you're not in the thick of the problem, and sometimes I should take my own advice; BUT walk yourself through the process of the air cooling through both the outdoor and indoor units and make sure that each "step" can be accounted for and the parts have either been inspected or you can validate they are in working order.

Best of luck!

Duke

 

After doing a bit of reading myself, I still think it has something to do with the evaporator on my unit...

After watching the repair guy at the condensor unit reading pressures and temps and me reading a reference chart that was provided by TRANE or one of the major manufacturers (which referenced temps, pressures, etc) and seeing that everything was showing to be within spec, I'm almost convinced that it's the evaporator.

Unfortunately, I'm not going to have time to look at it until Sunday at the earliest -- Happy first fathers day to me.

I didn't remove the plenum tonight but rather went in through the cold air output duct and sprayed downward. I don't think that much of the pressure from the spray bottle of DI water actually made it down through the evaporator fins but rather just ran out the bottom and out the drain line.

I guess I'm going to have to figure out how to remove that plenum (it's siliconed in there and is pretty damn secure) so that I can get to the underside of the evaporator.

Here's a good link... I've really learned a lot about systems, in general, during this process...
http://home.howstuffworks.com/how-to...nditioners.htm

-RP-