1. Welcome to Hvacproforums, an interactive community exclusively for HVAC professionals. The collective years of HVAC experience and the knowledge our forum members share make this an invaluable resource for those in the HVAC industry. We have a lot of fun, but make no mistake, we are pros. Hvacproforums is self supporting ...there are NO advertisers here. Do-it-yourselfers and Homeowners are encouraged to seek information elsewhere. Those involved in the HVAC industry are urged to register. its 100% free and easy, Once registered you will have access to the technical forums, Be sure to click over to the new members forum and introduce yourself after registering!

Blower Motor

Discussion in 'Residential' started by kena, Jan 22, 2018.

  1. kena

    kena New Member

    Messages:
    783
    Do some older furnaces have the blower motor turn on before ignition. I have a couple of techs who can’t figure out what is wrong with an old furnace. I had them jump C & W and the inducer starts, but nothing else happens. I had them check the pressure switch and all of the safeties. Everything seems ok. So I had them jump C & G and they got 120 volts at the board, but motor wouldn’t start. I had them ohm the capacitor out and it’ no good. I don’t recall ever having a blower moter prevent ignition. Any ideas?
     
  2. heavyevans

    heavyevans FNG

    Messages:
    1,316
    Location:
    Indy
    Never jump out C with any other terminal.
     
  3. kena

    kena New Member

    Messages:
    783
    Why? It’s a good way to tell if the issue is within the equipment or out. I have had tech support from several equipment companies have me jump out C & W. And the board is protected with a fuse.
     
  4. HMD

    HMD does it matter?

    Messages:
    94,298
    Location:
    here
    :popcorn:
     
    VTP99 and LemonWizard like this.
  5. Texas-Tech

    Texas-Tech Official Geezer*

    Messages:
    18,131
    Location:
    duhh
    I have never heard of doing that, ever.
     
  6. knave

    knave Undeterred

    Messages:
    8,391
    Location:
    NWWI
    Are you 100% sure that you don’t mean “R” & “W”?
     
  7. Joeysmith

    Joeysmith New Member

    Messages:
    386
    Jumping C to anything shouldn't bring anything on. C to R will get you sparks or smoke.
     
  8. knave

    knave Undeterred

    Messages:
    8,391
    Location:
    NWWI
    Unless it’s C as in common 24v on a novar EIM
     
    mike1020 likes this.
  9. Joeysmith

    Joeysmith New Member

    Messages:
    386
    C to W might fool the board into a fault and bring on inducer I suppose but never tried it.
     
  10. kena

    kena New Member

    Messages:
    783
    Ok... any ideas about the blower motor capacitor being the reason it wont fire? Usually blower comes on after ignition.
     
  11. knave

    knave Undeterred

    Messages:
    8,391
    Location:
    NWWI
    You should have more experience in this stuff before running a business just my opinion.
     
    VTP99, HMD, mike1020 and 1 other person like this.
  12. heavyevans

    heavyevans FNG

    Messages:
    1,316
    Location:
    Indy
    Capacitors are rated at Farads not Ohms.
     
    HMD and Zman like this.
  13. kena

    kena New Member

    Messages:
    783
    Ugh... I fix furnaces all the time. The capacitor is 10 Farads.

    My techs get 24 volts from the thermostat but nothing happens. Inducer dorsn’t start. So entire sequence doesn’t run. No auto draft inducer... high efficiency. All safeties ohm out fine. Only thing they can find is the blower capacitor is kaputz!!
     
  14. kena

    kena New Member

    Messages:
    783
    I’m just asking for suggestions, not opinions of my skills. But thanks for the enlightenment!
     
  15. Joeysmith

    Joeysmith New Member

    Messages:
    386
    Ok this is going to sound prickish but not meant that way. I have seen it twice in real life and this is reminding me of it.
    You stroking out or got something medical going on or just a really bad day? This is some pretty simple stuff your are getting confused on.
     
    Zman likes this.
  16. doc havoc

    doc havoc A cunning linguist

    Messages:
    9,777
    Location:
    45.780245, -91.731582
    If you have 24 volts between W and C, and the ignition sequence isn't starting, my immediate guess would be the board or the inducer motor. Provided no safeties are open and all wires are electrically sound and connected. And if you're using a jumper wire, put it on R and W to initiate a call for heat, not W and C.
     
  17. knave

    knave Undeterred

    Messages:
    8,391
    Location:
    NWWI
  18. kena

    kena New Member

    Messages:
    783
    Board is brand new!
     
  19. knave

    knave Undeterred

    Messages:
    8,391
    Location:
    NWWI
    Blower broken could cause high limit to trip and possibly lockout the furnace, some Trane/Amstd ones lock out after several high limit trips.
     
  20. kena

    kena New Member

    Messages:
    783
    Yes, it actually does sound prickish. Songlad you didn’t mean it that way. All safeties ohm out. If they jump out C & W the inducer comes on. Regardless of who agrees not to do that. Red and White wired to the board is calling for heat.