Results 1 to 5 of 5
  1. #1

    miller oil furnace cmf60-po

    I am having a issue with the oil primary control going into lockout when the fan limit control reaches fan on setting. Fan control relay settings 90 off 110 on high limit 165 Using a honeywell l4064b fan limit and a honey well r4184g oil control. Fires up great. t-stat will shut off burner at temp But if it needs to run up to fan control temp goes into lock out.

  2. #2
    Join Date
    May 2006
    Posts
    404

    Talking

    i own the CMF80PO the bigger version of youre furance.
    sounds like the heat exchanger might have a crack in it.
    as it works fine untill the blower turns on.
    have it checked


    Quote Originally Posted by jedwardson66 View Post
    I am having a issue with the oil primary control going into lockout when the fan limit control reaches fan on setting. Fan control relay settings 90 off 110 on high limit 165 Using a honeywell l4064b fan limit and a honey well r4184g oil control. Fires up great. t-stat will shut off burner at temp But if it needs to run up to fan control temp goes into lock out.

  3. #3
    Join Date
    Feb 2008
    Location
    Altmar, New York, United States
    Posts
    4,991
    ditto. you might want to get it checked as soon as possable.

  4. #4
    Join Date
    Sep 2002
    Location
    Northeast Ohio
    Posts
    4,855
    Quote Originally Posted by snupytcb View Post
    ditto. you might want to get it checked as soon as possable.
    Good advise. Those two controls have absolutely nothing to do with each other from an operational standpoint that would cause the primary to lock out. When the fan comes on, it is causing a lean out condition of the flame which in turn is causing the lock out. Breached HX is the most likely cause, it needs to be checked.
    A good HVAC tech knows how, an educated HVAC tech knows why!

    DEM


  5. #5
    Thanks for the info
    Will check the heat exchanger furnace is down until repaired

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  
Comfortech Show Promo Image

Related Forums

Plumbing Talks | Contractor Magazine
Forums | Electrical Construction & Maintenance (EC&M) Magazine
Comfortech365 Virtual Event