Lennox A/C condensor fan motor

Discussion in 'HVAC' started by GWS, Nov 15, 2007.

  1. Nov 15, 2007 #1

    GWS

    GWS

    GWS

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    I am new to forum. I have a Lennox model # HS26-036-2P whole house A/C unit. The fan motor in the outside condensor,
    (Emerson motor Part # 65G6001) will only run if I give the fan blade a little push than it seems to run OK. Does this sound like the motor is going bad or is there a starter type relay or something else that could cause this. thanks in advance

    GWS
     
  2. Nov 15, 2007 #2

    glennjanie

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    Welcome GWS:
    The problem may be the capicitor on the motor. It would be a 1' X 3"~ piece on the motor housing or off to the side. It changes the wave pattern and boosts the power for the start.
    To test it, you need to remove it from the circut; turn the power off at the outdoor disconnect and seperate the two wires that are connected to the capicitor. Use an audible signal OHMmeter to contact the two leads to the capicitor; it should come in with a loud, high whistle and taper off quickly to nothing. High to low in 1 to 3 seconds means the capicitor is good. No whistle means it is bad and needs to be replaced.
    If the capacitor tests 'good' then the motor is failing and should be replaced; the capicitor should be replaced along with the motor just to keep from having to go through all that again in another year.
    Glenn
     
  3. Nov 21, 2007 #3

    GWS

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    Thank you Glenn I will try that
     
  4. Nov 29, 2007 #4

    GWS

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    Hi Glenn, I put in new condensor fan motor and new capacitor the fan came on, but it only ran for about an hour and shut off again. The inside fan blows cold air through the hous but the outside condensor fan won't start again.
    ANy suggestions as to what to try next?

    Thanks
    GWS
     
  5. Nov 29, 2007 #5

    GWS

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    Sorry Glenn I am new at forums and may have asked you new question more than once. > I put in new condensor fan and capacitor, fan came on but only ran about an hour and shut off. The inside fan blows cold air through registers but the outside condensor fan doesn't come on. Any suggestions?

    Thanks
    GWS
     
  6. Nov 29, 2007 #6

    glennjanie

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    Hello GWS:
    Evidently you have power to the unit and with the new fan and motor, you have only to look at the control wiring. Does the compressor come on without the condenser fan? If not, check the transformer which is fed by larger wires of 240v and on the output side where the small wires are should measure 24v. Once you eliminate the transformer, check to see if the 24v is getting to the outside unit. Then, finally, it is possible the thermostat is bad.
    Glenn
     
  7. Nov 29, 2007 #7

    Kashka

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    GWS

    It may also be a good idea to verify the VA or load voltage rating on the transformer. If it is too low, this could be the cause of your woes.
     
  8. Nov 30, 2007 #8

    GWS

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    I checkrd transformer it seems to be OK. I was looking at outside unit this am. I used a wooden dowl rod and pushed the contact points together and the compressor and fan came on and ran until I released pressure on points. I pushed what appeared to be a reset button and the unit ran for about 15 minutes. Could this contact be bad? Should I cut power, take the contact off and try to clean it's points or assume it's bad and replace it.

    Thanks again for any help

    GWS
     
  9. Nov 30, 2007 #9

    Kashka

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    -Lower the set point on the t'stat so the unit will call for cooling.
    -Measure the voltage on the coil of the contactor to be sure you are getting 24VAC.
    -Then puch the contactor and release it and see if it stays in. If it does thne there may be a VA porblem, where the current is not enough to pull in the contactor. I doubt verymuch that this is the issue because this normally happens on long wire runs.
    -If the contactor does not not stay in then it is bad and needs to be changed.
     
  10. Dec 1, 2007 #10

    GWS

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    Thanks for all the help. So far today it's been working OK. Keeping my fingers crossed.
    Thanks again
    GWS
     
  11. Dec 1, 2007 #11

    glennjanie

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    YYEEAAAAaaa! YabaDabaDo! Way to go. The reset may have been the problem all along. It is embarassing to replace a part and find the problem somewhere else. Yes, I have done it a few times too.
    Glenn
     
  12. Dec 3, 2007 #12

    inspectorD

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    I just love it when a plan comes together.:D
     
  13. Jan 30, 2008 #13

    jimtxas

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    I also have a lennox condensor and have noticed on occassion a rather loud buzzing/humming noise from the unit and when i go check on it i notice the fan isn't turning but it sure is buzzing. This morning and during some snowy days i've notcied the outside fins kind of frosted up. Other times the fan is turning fine. Inside everything heats and cools just fine -- so far. Is the fan always supposed to turn? If so what might be the problem? You mention a 'reset' what is this and where is it?

    Thanks so much for your help.
     
  14. Jan 31, 2008 #14

    glennjanie

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    Hello JimTxas:
    No, the fan doesn't have to turn all the time. When the unit frosts up the compressor pumps up a good head pressure (which creates hot gasses) and the reversing valve releases the hot gasses quickly to de-frost the outdoor unit. The loud buzzind is probably a contactor that has pitted contact points on it; it makes a loud chatter of a buzz.
    Glenn
     
  15. Jan 31, 2008 #15

    kok328

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    I'm not clear on what reset button was pushed but, some icing on the lines is OK. If the evaporator coils are iced, then your system is low on charge. Also, if your contactor is worn and chattering, it could cost you a new compressor. I suspect that the compressor tripped out on hi-pressure (due to not having a fan to prevent overheating) and was reset (red, rubber covered button)? Which would explain a lot and put other items of concern into focus.
     
  16. Feb 1, 2008 #16

    jimtxas

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    Thanks much for your response. I went ahead and took the motor and capicitor down to the AC shop today. They tested the cap and said it was good and hooked them both up to power and confirmed a dead motor. The buzz was from the motor... when it would kick on it would make about a quarter turn and just hang... i could try and turn it with my hand it would kick around a little and hang again.

    Any way, took home a new motor for $90, put it all back together only to find out i had a really powerful vaccum cleaner. It sucked the box to the top! Anyway, this motor had the ability to spin either way, so i swapped the wires that control the direction and was back in business.

    I suspected the frost on the coils was due to no air being sucked through them. Since it's been going again, no frost.

    Im a bit disappointed that motor didn't last longer. It's only a 4 year old unit. Anything i can do to prolong its life? Should i gutter the eave on my house above it to keep run off from going in it? Does it matter?

    Im curious though, for heating, why does the outside compressor and unit run? What's its advantage? Also, whats the difference btwn heat and emergency heat? Emer heat comes on when thers a 2 degree or more difference...

    This site is really great -- save me over $200 today. Thanks for your help!

    J
     
  17. Feb 1, 2008 #17

    guyod

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    If your roof water pours right into the unit then thats defiantily why it only lasted 4 year.

    Gutters will work or if you dont want to go through all that trouble some type of roof over the unit will work too just make sure you keep it 18'' above the unit. Gutter will also protect your foundation too so that is your best option.
     
  18. Feb 1, 2008 #18

    glennjanie

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    Hello JimTxas:
    The function of the heat pump is to move heat around for you comfort and convenience. In the summer it pumps the heat to the outside. When you switch to heat a reversing valve changes places with the evaporator coil and the condenser coil, so to speak. The outside fan must run either way to help with the exchange of heat. For heat use the heat pump becomes inefficient as the temperature drops; when you hit 17* it can't extract any more heat from the outside air so it goes into 'supplemental' heat mode or 'emergency' heat mode. Emergency means the compressor shuts down and the house is heated with resistant electric heat coils (there went all the efficiency).
    If you should decide to build a roof over the outdoor unit, please check with the manufacturer first. Some of them say they don't want any roof and some have distance allowances. Anything that impedes the exhaust of the fan will knock the efficiency.
    Glenn
     
  19. Jan 2, 2009 #19

    rseeley3

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    I just read the question on the Lennox whole house air conditioning fan motor not turning unless he gives it a push. You said it may be the capacitor, I do not own a AUDIBLE signal OHMmeter. I do have a regular Ohmeter could you tell me if I can chek with that and how do I go about it.
     
  20. Jan 3, 2009 #20

    glennjanie

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    Hello RSEeley:
    The regular ohm meter will check the capicitor also. Disconnect the wires to the capicitor and watch the dial on the ohmmeter, when you touch the terminals on the capicitor the needle should go all the way to the right very quickly and return a little slower. This all happens in about 3 seconds so it is very improtant to be watching.
    Glenn
     

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