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  1. #1

    High fan speed! condenser ?

    I just had a York affinity czf 16 seer 3 ton single stage unit installed,everything works fine but the fan speed seems very strange.
    when the unit (condenser) kicks on it vibrates the unit very loud then drops to normal speed this all happens in about 5 secs.the spec sheet says its an 850 rpm single speed fan,this does'nt seem like a big deal but when the fan races the whole unit vibrates loud until the fan slows,this unit is near my bedroom window and near the patio,The unit itself it pretty quiet and I cant hear it from the bedroom until it kicks on (sometimes wakes me up from the fast vibration),my questions are why is the fan doing this?
    can I make it turn on at a normal 1 speed so there is no vibration ? or stop it from raising to a higher speed? If not, do you have a idea
    how to stop the vibrations from the motor against the grill? Thanks for the info in advance!

  2. #2
    Join Date
    Jan 2004
    Location
    Lancaster PA
    Posts
    68,331
    Call the contractor back. Its under warranty.
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    How many times must one fix something before it is fixed?

  3. #3
    Join Date
    Oct 2010
    Location
    Anderson, South Carolina, United States
    Posts
    7,480
    Sounds like a problem, the motor shouldn't change speeds at all.

  4. #4
    Ok guys thanx! I will give my ac guy a call and let's see what he says

  5. #5
    Hi ,Ok I had my AC guys check out the the motor and he agrees thats the problem,BTW the motor wasnt speeding up just sounded that way sorry thats my bad.The problem is the motor starts very slow with a slight whining sound then right before it hits max speed it vibrates then smoothens out,It sound like the motor is struggling to turn the fan blade,anyway my ac guy changed to a new motor and still have the same problem,The motor is a 1/4 hp 850 rpm Emerson (US) motor ,we did test the cap and it does seem fine,and the fan blade seems straight ,I was thinking to change the motor to a AO smith motor is my next guess,Any suggestions will be appreciated Thanx!

  6. #6
    Join Date
    Aug 2003
    Location
    Fort Worth, TX
    Posts
    11,358
    I have to wonder if it's the compressor instead of the fan, if it is pumping liquid upon startup, which sounds horrible until the liquid clears the compressor. This problem can be caused by overcharge, or liquid forming in the compressor sump during the off cycle. If you learn to distinguish the pitch of the compressor sound from the fan sound, the humming (pitch) of the compressor will turn into a loud, gutteral roar in the same pitch if it indeed is pumping liquid. Kind of like a: hhmmmmRAAAHHHHmmmmmm sound.

    If the unit gets loud and stays that way, we're then talking about a different possibility.
    • Electricity makes refrigeration happen.
    • Refrigeration makes the HVAC psychrometric process happen.
    • HVAC pyschrometrics is what makes indoor human comfort happen...IF the ducts AND the building envelope cooperate.


    A building is NOT beautiful unless it is also comfortable.

  7. #7
    Join Date
    Jan 2004
    Location
    Lancaster PA
    Posts
    68,331
    Slipping hub.
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    How-to-apply-for-Professional

    How many times must one fix something before it is fixed?

  8. #8
    Join Date
    Aug 2013
    Location
    Pennsylvania
    Posts
    50
    not sure if that unit would have it or not but i know some york 10 ton units R 410a have an ambient air head pressure control which takes single speed motors and pulses them giving the illusion they are variable speed. these units start up and makes a lot of vibration then the motors calm down and it goes away. for a couple of nuisance grills i had to take some calking and place a bead on the grill where it vibrated nonstop.

  9. #9
    Join Date
    Aug 2013
    Location
    Pennsylvania
    Posts
    50
    however shophound could be right that it could be the compressor.

  10. #10
    Thanks for the quick replys , I'm 99.9% sure it's the fan motor just not sure of the reason why it vibrates before max speed , I will unplug the fan motor for a couple of seconds just to make sure it's not the compressor ,I really think its just a cheap motor/noisy , or something is up with the capacitor ,my plan is to change the cap first , if that doesn't work change the motor to an AO smith compatible .
    Thanx

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