1. Welcome Hearth.com Guests and Visitors - Please enjoy our forums!
    Hearth.com GOLD Sponsors who help bring the site content to you:
    Hearthstone Soapstone and Cast-Iron stoves( Wood, Gas or Pellet Stoves and Inserts)
    Caluwe - Passion for Fire and Water ( Pellet and Wood Hydronic and Space Heating)

Central AC evaporator A coil cleaning and orientation question?

Post in 'DIY and General non-hearth advice' started by Don2222, Aug 14, 2012.

  1. Don2222

    Don2222 Minister of Fire

    Joined:
    Feb 1, 2010
    Messages:
    6,840
    Loc:
    Salem NH
    Hello

    I cleaned the Condeser Coils with the foam cleaner and hosed it off.
    Also replaced starting capacitor and 30 amp panel breaker in main breaker panel inside house.
    See detail and pics in link below.
    http://www.hearth.com/talk/threads/...r-buzzing-after-the-coil-cleaning-help.88931/

    Now, I picked up a can of the old evapakleen!
    See pic 1

    This old Lenox seems different. It is located in the attic.
    The return air comes into the right side into the top of the A part of the A Coil which is lying on it's side!
    So the base of the A coil is where the Evaporator Fan is located!
    See pic 2-5

    1st Question
    Is this the normal configuration? Is it the best configuration?

    So I ran the shop vac over everything gently and then sprayed the evapakleen all over it.
    See pic 6
    Then put it back together and used foil tape to fix a few leaks in ducting around the attic.

    2nd Question
    How can I tell if the evaporator fan is weak and not blowing enough air?
    The motor shaft is real rusty looking!

    The air does feel a little cooler coming out now. It still takes time to cool the house down but everything is running and working.

    Attached Files:

    Helpful Sponsor Ads!





  2. woodgeek

    woodgeek Minister of Fire

    Joined:
    Jan 27, 2008
    Messages:
    2,526
    Loc:
    SE PA
    Buy a cheap anemometer (<$30), and measure the face velocity on the return. Multiply the velocity in feet per minute by the area in ft2 to get cfm. Ideally, should be over 300 cfm/ton. Less than 200 cfm per ton is pretty weak.
  3. blujacket

    blujacket Minister of Fire

    Joined:
    Oct 2, 2008
    Messages:
    616
    Loc:
    West Carrollton,Ohio
    Never heard of a motor getting weak,it either works or it doesn't. That coil looks clean. I assume they do have a filter located in the conditioned space return? A properly sized system will take awhile to cool down a house when it's been off for awhile. Need to remove the humidity before temp will reach set point.
  4. Defiant

    Defiant Vermont Castings Geek

    Joined:
    Dec 5, 2007
    Messages:
    2,112
    Loc:
    Old Lyme CT
    [​IMG]
    MasterMech and seige101 like this.
  5. Don2222

    Don2222 Minister of Fire

    Joined:
    Feb 1, 2010
    Messages:
    6,840
    Loc:
    Salem NH
    Thanks, It was not cooling the house down last night after I cleaned the condensor even though the line was cold and there seemed to be enough R22 freon. The Humidity was wicked high last night. Anyway, I vacuumed out the evaporator and used the foam cleaner like the instructions said.
    I did vacuum the return air filter last night so it looked like brand new!

    Still seems like the old rust evap fan could be doing better.

    Any links to a good cheap anemometer?
  6. blujacket

    blujacket Minister of Fire

    Joined:
    Oct 2, 2008
    Messages:
    616
    Loc:
    West Carrollton,Ohio
    Those motors scream when they are bad. You can check to see what speed the motor is set at and go to a higher one.
  7. heat seeker

    heat seeker Minister of Fire

    Joined:
    Feb 25, 2011
    Messages:
    1,928
    Loc:
    Northern CT
    What is the discharge air temp at the vents? Mine seems to be about 10 to 15 degrees below the room temp, on a fairly new system after it's been running a few minutes. That doesn't seem like much, but with a large volume of air moving, it cools the house pretty darn well.
  8. Don2222

    Don2222 Minister of Fire

    Joined:
    Feb 1, 2010
    Messages:
    6,840
    Loc:
    Salem NH

    So if I get one like this for $13.15 and it measures in Meters Per Second.
    http://www.ebay.com/itm/Digital-LCD...ther_Meters&hash=item48451b964d#ht_4657wt_974

    1 meter per second = 196.850394 feet per minute

    So if I measure 0.254 Meters per second

    Then 196.8*0.254

    That is 49.9 or 50 feet per minute

    The area of the return plenum is 24" x 24"
    or 2' x 2 ' = 4 Ft2

    So 4x50 = 200 CFM

    Is that correct?
  9. woodgeek

    woodgeek Minister of Fire

    Joined:
    Jan 27, 2008
    Messages:
    2,526
    Loc:
    SE PA
  10. Don2222

    Don2222 Minister of Fire

    Joined:
    Feb 1, 2010
    Messages:
    6,840
    Loc:
    Salem NH
  11. blujacket

    blujacket Minister of Fire

    Joined:
    Oct 2, 2008
    Messages:
    616
    Loc:
    West Carrollton,Ohio
    Time to ohm compressor for short. To trip that 30amp breaker, I would guess your compressor is shot.
  12. Don2222

    Don2222 Minister of Fire

    Joined:
    Feb 1, 2010
    Messages:
    6,840
    Loc:
    Salem NH
    I think you are correct. I tried the contactor first, because if the contacts were pitted and high resistance it might be a problem. So if it still quits and it may have, then you are right it is the compressor!
  13. DexterDay

    DexterDay Guest

    I just had my system serviced and after checking pressures in the lines. He went outside and cleaned the coils (with just water) and told me to stay away from the detergents and foam cleaners. They can do more harm than good (oxidation, etches the metal, making dirt and other particles stick easier) and it also voids my warranty (2 yrs left on my 10 yr)..

    This is where Heat seeker is on to something above. . . . . . .

    Then he checked the return and discharge air. A 15° difference is industry standard, they shoot for 17° and above (mine was at 21°) But by checking the temps, you will know if your system needs charged or not. And if you really do have an underlying problem. With a slowing fan motor, your air temps should be cooler? (Return/Discharge).

    (Oh and it was only $65 for a service call that lasted over an hour and the guy let me follow him and he explained everything in detail. It was a very good learning experience)
  14. Don2222

    Don2222 Minister of Fire

    Joined:
    Feb 1, 2010
    Messages:
    6,840
    Loc:
    Salem NH
    Very good, you got a good deal and great info. Thanks
    The outside unit usually just has the condeser coils, the fan and the compressor, Did he clean the Evaporator A Coil and fan that circulates the air inside? The evaporator is usually located in the Attic.

    I talked to my neighbor and the AC ran all last night after changing the Contactor but her son today said the breaker still trips when it gets real hot outside! So before I ohm out the Compressor we should try a "Hard Start Kit" :)
    http://www.grainger.com/Grainger/SUPCO-Hard-Start-Kit-4E240
  15. boosted3g

    boosted3g Feeling the Heat

    Joined:
    Aug 3, 2012
    Messages:
    270
    Loc:
    Central PA
    When you are talking about temperature it is much better to use the superheat and sub cooling temperatures and compare them with ambient air temp and pressures with your installation manual chart. If it was far off it would be more of a refrigerant issue and although the compressor may shut down due to high or low head pressure it wouldn't blow the breaker. I have seen a tight condenser fan pop a break but the compressor is usually where the problem lies. Try replacing the breaker first since its cheap and easy. It the AC is more than 10 years old it would most likely pay you to replace it especially since this is the last year for the tax rebates. If you find your compressor is bad don't even bother fixing it. Just replace the system and move to r410 assuming your still on r22 since you said old Lennox.

    This is a configuration call horizontal left side. I personally like the coil where the incoming air goes through the coil the opposite end but it may not have been able to be configures like that due to condensate and refrigerant line locations. I am not familiar with Lennox at all but there is honestly not much difference in design from all the manufactures. Some just use better materials than others.

Share This Page