Slow ceiling fan...

Discussion in 'Electrical Forum discussion & Blog' started by Donavan, Feb 7, 2021.

  1. Donavan

    Donavan New Member

    Joined:
    Feb 7, 2021
    Location:
    Texas
    Hello all-

    We are new owners of an existing property. I'm unsure of the age of the fan in the living room, which doesn't run as fast as it should at it's highest setting.

    The pull switch is on "high". It's light kit is on a separate wall switch (lights are bright), & the fan speed is controlled by a dial type wall switch marked "off, low, med, high, off".

    Where should I start to diagnose? I have a meter and I'm handy.

    Thank you in advance!
     
  2. Reach4

    Reach4 Well-Known Member

    Joined:
    Sep 25, 2013
    Location:
    IL
    Unless it is fun for you, it's going to be easier, and maybe cheaper, to buy a new ceiling fan. This assumes you are not talking about a really expensive fan.
     
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  4. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Joined:
    Sep 2, 2004
    Occupation:
    Retired Systems engineer for defense industry.
    Location:
    New England
    The switch may be bad. When on high, you should see the full 120vac going into the fan, and less at each other setting (at least for most fans).

    A more definitive answer may be easier if we knew the make/model of the fan.
     
  5. wwhitney

    wwhitney Well-Known Member

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    Mar 17, 2019
    Location:
    Berkeley, CA
    Step one for trouble shooting, assuming the ability to do the work safely, would be to bypass the wall speed switch to see if the fan behaves properly. That will tell you if the problem is the fan or the wall speed switch.

    Cheers, Wayne
     
  6. Reach4

    Reach4 Well-Known Member

    Joined:
    Sep 25, 2013
    Location:
    IL
    I think you are saying that the fan on high doesn't run faster than on other settings.

    I worked to fix a ceiling fan. Troubleshooting to determine if the problem was the multi-wire switch or the multi-wire capacitor, and trying to find the right replacement part. At some point I just wanted it to , and got a new one for under $100. Works well. I should have done that sooner.

    This is not to say that there are not fancy ceiling fans worth fixing.
     
  7. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Joined:
    Sep 2, 2004
    Occupation:
    Retired Systems engineer for defense industry.
    Location:
    New England
    There are various ways you can control the speed of a fan. Some have different windings, some do it with a DC motor (not that common), and you could do it with PWM. So, without knowing what fan you have, it's really hard to say. The two ceiling fans I have, always have 120vac going in, and the switch sends a digital message on top of the ac that the fan interprets on what speed to run, and it can reverse it, plus turn the lights on/off and dim them with only two wires (power) going into it. There's a big variation on how it's done.

    I'd measure the voltage going into the fan and see what I had. Now, interpreting that may be the harder part, but something has to change as you put the switch in a different position...see if it does, and what levels come out.
     
  8. WorthFlorida

    WorthFlorida The wife is still training me.

    Joined:
    Oct 28, 2009
    Occupation:
    Retired
    Location:
    Orlando, Florida
    Inside the housing of all AC motor fans is a multiwire capacitor that is used for fan speed control. Over the years I only had to change two capacitors. You need to open the bottom part where the fan light wiring is and you see it. There are several different ratings made so you must look at the one to get the numbers off of it. You can buy these on line for a few dollars and if you're handy with electric wiring, it's doable. You need to cut off the crimp wire nuts and get yourself the small gray color wire nuts. It is a tight fit and PITA sometimes to get it all back together.
    I had one fan that ran kinda ran slow and I replaced the capacitor. For this one fan the new cap only made a slight difference in speed so I chalked it up the fan design itself. It came with the house when we bought it and it was only a few years old then and nice looking.

    This is where I bought my caps. It has a nice chart on the dozens of different ratings
    https://eceilingfans.com/capacitors_-_ceiling_fans.html

    The fan motor switch is a push in connector and next to the wire is a slot for a small screwdriver to push the tab in to realise the wire. The replacement should have a soldered end so it can be pushed into the switch. Do note that if you get a replacement switch, get one for a fan motor. The light switch looks identical but it is internally different.

    A typical capacitor.
    [​IMG]

    Basic wiring to the fan motor switch.
    [​IMG]


    [​IMG]
     
  9. Reach4

    Reach4 Well-Known Member

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    Sep 25, 2013
    Location:
    IL
    How does that compare to the number of multi-wire fan switches?
     
  10. WorthFlorida

    WorthFlorida The wife is still training me.

    Joined:
    Oct 28, 2009
    Occupation:
    Retired
    Location:
    Orlando, Florida
    I've had a few break. Florida homes have fan in almost every room has a fan. My last home had five and my current home has six. All but one are controlled by the speed switch on the other is a DC motor controlled with a remote.
    Another cause of slow fan speeds is when a wall variable fan speed switch is used. The problem is the fan switch gets changed to the slow speed then the wall control won't work as well or the fan. If a wall control is used the ceiling fan must be left on Hi.
     
    Last edited: Feb 9, 2021
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