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A/c is weak!

rmousir

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Jan 31, 2009
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116
Hey all,

I have a ranch house with a basement. My a/c has been barely able to keep the house at 77 this summer with this crazy heat. House is 10 years old. insulation is good but not great. When the a/c is running and with no filter in the system I can put my hand over the vent and barely feel a breeze. My mother in law has a wind storm in comparison.

Now I have my a/c serviced every 2 years. Last time the guy was out, I asked about having the blower turned up to a higher speed. He told me it was up as fast as it can go.

So my thought is, I do get nice cold air but I have very little cfm push. Can I swap out the blower to make more cfm?

I guess I am stuck here. Thoughts and suggestions are most welcome. I don't want to replace the system just yet. At least for a couple of more years.

Thanks.
Richard.
 
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Falcon67

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You should have someone check the A coil on the inside unit for debris clogging. The blowe has to move the air across the cooling coils and if they have been allowed to accumulate dirt over the years, it will really kill the flow.

If the blower has a defect, it can be replaced but they don't sell "faster" anything for a specific system. It is what it is and upgrades require replacement of the air handler and usually the condenser since they are a matched set.
 
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rmousir

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I can check those. can't be to hard to get at them and give them a good cleaning with the vacuum or a a air hose.

So even if I got a replacement blower it won't be more cfms?
 

ElectroLight

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There's a lot here but: Check to see if the unit is iced up, or as noted, evaporator coil clogged with dirt. You should always run a filter. The fan speed may be adjusted with a pulley change if so equipped. The system could also be low on gas...
 
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rmousir

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I've never cleaned the internal coil in the unit before. After some reading I am going to start there first when I get home tonight.

For the record, I do run a filter. Only took it out to do a test and see how the cfm was with out it.

I will keep you posted.
 

Bronson

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You can get a special coil cleaner at a Rerigeration supply house, or the Chain stores. Follow the directions! Chances are , You air handler is a direct drive ,as in ,no belt or pulleys. Often the blower (squirrell cage) is dirty itself and impedes air flow. Carefully remove the blower wheel and take it to the car wash and clean it thoroughly. If the motor has oil ports, put a few drops of 30 wt oil in them. Clean the A-coil with the coil cleaner, then re-assemble. DO NOT FORGET TO KILL ALL POWER TO THE UNIT BEFORE YOU START. If You still have a problem, You are probbly low on freon. If You ever see ice on any of the copper lines, inside or outside, there is either a air restriction, or low freon. The suction line at the outside condensing unit, should be cold to the touch,even sweating when the unit is running, dependiong on the humidity in Your area. You should also go into the attic and check all the ducts, to make sure You are not cooling the attic! I have seen that many times. Often, the helpers that install the air ducts are novices, and in the heat of an attic, rush their work and make sloppy connections. Good luck.
 
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Bronson

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BTW, get a good washable filter, the Green mesh type, at lowes,etc. Do not waste Your time or money on the paper framed cheapo filters. They are useless. You get what you pay for.
 

HVAC Phil

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In addition to the other responses, the ductwork could be inadequate for the job. This is more common than dirty coils.
 

Falcon67

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Read the label on the cleaner - I used industrial strength stuff that is basically phosphoric acid. Your skin will not like it, it'll eat you up.

Also good call on the icing - if the system is low, it may freeze up and that will kill air flow quick.
 

rickairmedic

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Ok lets start at the beginning . What type of system do you have ? Do you have an airconditioner and a gas furnace or do you have a heatpump and electric furnace ? This WILL make a differance on cleaning your evaporator coil. You need to get to the bottom of the evap coil in order to clean it properly . On a heat pump system this is fairly easy simply remove the panels on the front of the unit and the coil should be slanted from one side to the other which means you can get to the top and bottom of the coil fairly easy. With gas heat you will have an evap coil sitting ontop of the furnace ( possible inside a seperate case but not always ). This coil is a bit more of a pain in the backside to clean . You will have 2 options 1 pull the coil out of the case ( carefully so you dont kink the lineset ) :D . The other option is to ( again very carefully ) remove the upside down triangle shaped inner cover off of the front of the coil ( did I mention be extremely carefull if you choose this option ) there are TINY refrigerant lines on the front of the coil that you can break by pushing on them with the traingle cover .


Ok now that we have access to the coil we will need a decent 1 or so gallon garden sprayer and a gallon of " evaporator coil cleaner ) you can get the cleaner from most HVAC supply houses while you are there grab a set of coil combs . You will also need a pair of safety glasses " you dont want this **** in your eyes it will fuch them up " . Once you have gained access to the bottom side of the coil get your flashlight and have a look up in there and see what it looks like . Is there a blanket of pet hair on the coil ? Well then remember those combs we got :D your gonna need one and a plastic grocery bag . Take one of the combs and " lightly " did I mention " lightly start combing the blanket off the coil " hint once you get it pulling up you can usually pull large sgeets off with your hands " . Ok now that we have the blanket removed mix up a half gallon of coil cleaner per instructions " this half gallon includes the water you will be mixing in not a complete half gallon of cleaner " . Ok now start spraying the top of the coil with the cleaner get a decent coat on the top . Now start spraying the bottom side of the coil. You should use up what you mixed up on the coil . :D Ok now while we let that sit 10-15 minutes lest go rinse out the sprayer and refill it with 1-2 gallons of fresh water " depending on how big a sprayer you got " . After the cleaner has sat for 10-15 minutes per instructions on the coil cleaner label :D start on the top of the coil with the fresh water and spray the topside off . Then start spraying the bottomside starting at the top and working down . Depending on how many years it has been since this was done it may take more than one application to get all the **** out of the coil . You will see little black dots of stuff running down the coil as you spray it once you stop seeing the black stuff comming out of the coil you are done .



I went to a house on sunday where several " techs " had been recently and couldnt tell the woman why her AC system wasnt cooling her house . "
One of the techs even cleaned the evap coil 2 differant times " . I got there and freon levels looked good but the temperature drop across the air handler was only 10* . I told her we have a problem and asked when the last time her coil had been cleaned . She told me it had been done twice recently . I at this point pulled the front panels off of the unit and looked at the bottom of the coil . EWWWW yuck nasty :D. I gave her my flashlight and asked her to take a look . I asked her if it looked clean needless to say she agreed it didnt it was **** nasty .


I spent the next hour using a gallon of coil cleaner and so many gallons of clear water " I lost count " to actually clean her evap coil. I told her when I was done that I wanted to come back in a month " didnt want to empty her purse then " and clean it again as I was sure there was still more gunk in the coil. She agreed to call me in a month for another mass cleaning . I talked to her today to see how it was doing and she was happy to say it hadnt gone over 80* in the house since sunday . I told her one more good cleaning and we should be able to keep the house even cooler .



Oh yeah air filters " I but the pleated filters from Lowes that come 3 in a pack for around $7.50 " not the 3M ones they **** and are expensive " . I do not recomend washable filters as you will not get them completely clean and lets face it $2.50 a month for air filters really isnt that expensive anyways and yes this means change it one=ce a month I dont care if the package says " good for 90 days " .


Oh yeah I agree to check the blower for dirt as long as you are in there however "DO NOT TAKE IT TO A CARWASH " . Blower wheels have little weights on them just like the wheels on your car and if you remove one with high pressure water and dont notice it missing then your blower wheel will now be off balance and piss your furnace off :D . I take the whole squirel cage outside and use a water hose on it with a decent nozzle on it . i then let it bake in the sun while I go back inside and finish cleaning the rest of the system " turn it upside down so that all the water runs out of it and the motor " while you are inside cleaning :D.


Rick
 
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ishiboo

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There's a lot here but: Check to see if the unit is iced up, or as noted, evaporator coil clogged with dirt. You should always run a filter. The fan speed may be adjusted with a pulley change if so equipped. The system could also be low on gas...

Agreed re: icing. My moms house occasionally ices over. The ice impedes airflow, so while the air is cold little air gets through.

If there's an easy place to remove to see the evaporator (look at where the AC lines enter the plenum), remove it and see if it's iced.

Otherwise, either shut it off for several hours and watch the condensate, and run it fan-only and see if the airflow is higher, or do what I do; turn the heat on full blast until the ice melts, then turn the AC back on :)
 

rickairmedic

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Agreed re: icing. My moms house occasionally ices over. The ice impedes airflow, so while the air is cold little air gets through.

If there's an easy place to remove to see the evaporator (look at where the AC lines enter the plenum), remove it and see if it's iced.

Otherwise, either shut it off for several hours and watch the condensate, and run it fan-only and see if the airflow is higher, or do what I do; turn the heat on full blast until the ice melts, then turn the AC back on :)


Then call a service tech as there is a reason the coil is icing up :D.


Rick
 
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Bronson

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I have cleaned lots of blowers at the car wash, never blown a weight off yet, but, good point, You dont want it out of balance. The cleaning job described is best left to a professional. And even them , about half will do a half-assed job.....Seems like most Techs want to just add Freon and go. My old Boss was the worst....:(
 

rickairmedic

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I have cleaned lots of blowers at the car wash, never blown a weight off yet, but, good point, You dont want it out of balance. The cleaning job described is best left to a professional. And even them , about half will do a half-assed job.....Seems like most Techs want to just add Freon and go. My old Boss was the worst....:(


Thus why I work for myself and dont have any " techs " working for me . Decent techs are darn near impossible to find here and licensed techs are even less likely to be found .


Rick
 

Jay41

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Grundy co. IL
I have cleaned lots of blowers at the car wash, never blown a weight off yet, but, good point, You dont want it out of balance. The cleaning job described is best left to a professional. And even them , about half will do a half-assed job.....Seems like most Techs want to just add Freon and go. My old Boss was the worst....:(

Never add refrigerant to a system without verifying cfm.:D

On every call.
 

Ocho

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DFW, Texas
Just throwing stuff out there...

Is it possible he has a hole in one of the ducts in the attic? I would think that would only affect one room, though.
 

mpire

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Just throwing stuff out there...

Is it possible he has a hole in one of the ducts in the attic? I would think that would only affect one room, though.
I found a hole had been chewed into my duct in my attic at my condo.

I foamed it up, and then found little bits of foam had been chewed away a month later.

I think the rats/squirrels had been enjoying my A/C
 
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rmousir

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OK guys! Thanks for all the good suggestions.

I live in a ranch and my ducting goes through the basement. I checked all my flaps and all my vents are right open but one, which is under a dresser.

I checked and changed my air filter. It wasn't very dirty at all but they are cheap so I did it anyway. It didn't make a difference.

I think took off the front cover of the area where the cooling filter is after leaving the a/c off for about 3 hours.
It was pretty clean. Now that was just the top part. It is shaped like a triangle with the underneath access covered. I think turned on the a/c and the blower and could feel decent push of air through the fins so it felt OK I guess.

Now that the weather isn't 105 out things are OK but I still feel like my a/c is week and that it doesn't push enough CFMs through the vents to do any real cooling when the house is super hot. We have a programmable tstat and use that but don't leave the a/c off. On super hot days it just can't cut the mustard.

Thoughts? Its a Lennox and my guess is it is the cheapest builders grade that they had in '99 when the house was built. I don't remember it ever doing a super job but then I've never had central a/c before.

Thanks.
 

rickairmedic

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Mousir I would be willing to bet that thqat A coil hasnt been cleaned since it was put in in 99 and that the underside of it is nasty and it is full of mold that is blocking your airflow. A house that new should be decently insulated as we were starting to " go green " at that time :D.

Rick
 
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rmousir

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Is there a way to get underneath that triangle coil set up and clean it out? I didn't see anything pop out at me. I'm willing to take the whole dame thing apart if need be but I don't want to get into breaking the lines or messing with freon. Can I just pull the side off or something like that?
 

rickairmedic

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There should be a panel attatched to the front of the triangle with 1/4" or 5/16" screws that you can remove ( carefully ) to gain access to the underside of the coil. The other option is to slide the entire coil out enough to gain acess to the bottom of the coil. A picture would help us to help you :D.

Rick
 

Coyote Red

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I'm sure the coil could use a cleaning. Can't they always?

But at 105 ambient many systems struggle cause they are typically sized for about a 100.

Hey, just turn your thermostat down. ;)
 
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rmousir

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thanks for that awesome info!

Well I took the back panel off my a/c set up. It rally wasn't to come off but I convinced it. I got a good look at the underside of the coils and they aren't all that dirty. I also checked the wind flow both below and above the coil (with a hand test :>) ) and it seems to be pretty strong on both sides. There was some dirty and I did what I could to clean it up gently but there wasn't much room to do a good job.

Should I get some of that coil cleaner spray? I read that will do the trick. Then I read that it will cause badness. Thoughts?

I also took a pile of pictures. Just need to transfer them to my computer. More to come.
 
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