Ask Me Help Desk

Ask Me Help Desk (https://www.askmehelpdesk.com/forum.php)
-   Heating & Air Conditioning (https://www.askmehelpdesk.com/forumdisplay.php?f=150)
-   -   Lennox Oil Burner Troubleshooting (https://www.askmehelpdesk.com/showthread.php?t=417260)

  • Nov 18, 2009, 03:29 PM
    rdkenney
    Lennox Oil Burner Troubleshooting
    HELP.

    I have a Lennox OF23Q3 oil burner. It is tripping out the safety button on the primary control erratically during operation. Sometimes it runs 20 minutes before tripping and sometimes only a few minutes. When it does trip the blower just constantly runs until the power is cut.

    I have changed filter, nozzle, cad cell, adjusted the electrodes. With no help. I have also jumped the cad cell terminals as described in the service manual. It did not trip off which is supposed to eliminate the primary control as a problem.

    Any idea what I should be looking at to repair it? Perhaps the blower control board?
  • Nov 18, 2009, 03:58 PM
    Joshdta

    Could be a weak transformer, or a air leak in the line. Or even a bad pump, did you bleed some oil in a cup and look to see how much air there was, or any water?
  • Nov 18, 2009, 04:04 PM
    KC13

    Was the burner firing (flame present) at the time you observed the primary control lockout? Does the CAD cell have a clear line-of-sight toward the firing assembly? I doubt the blower control is contributing to the problem in any fashion.
  • Nov 18, 2009, 04:13 PM
    rdkenney
    Quote:

    Originally Posted by KC13 View Post
    Was the burner firing (flame present) at the time you observed the primary control lockout? Does the CAD cell have a clear line-of-sight toward the firing assembly? I doubt the blower control is contributing to the problem in any fashion.

    The burner was firing and I believe the new cad cell is aimed right at the flame/electrodes

    I wonder why it would fire for 20 minutes before tripping the safety button? The safety button trips based on flame failure correct?
  • Nov 18, 2009, 04:14 PM
    rdkenney
    The pump was bled and is air free...
  • Nov 18, 2009, 04:16 PM
    KC13
    The CAD cell is very similar to a photocell. Its resistance varies with the level of exposure to light. The primary control is seeking an acceptable resistance value to prove successful ignition & sustained firing.
  • Nov 18, 2009, 04:17 PM
    KC13
    Check for pinched/damaged CAD cell leads.
  • Nov 18, 2009, 04:24 PM
    rdkenney
    OK I'll check the leads, perhaps replace them.

    The old cad cell was dirty so not to take a chance we just replaced it.

    Even though the furnace is 8 yrs old it is used in our 3 season 'camp' and has probably seen only a year's worth of use.

    Thanks for your help.
  • Nov 18, 2009, 04:27 PM
    KC13
    With fuel oil units, more problems arise as a result of sitting idle than from running. Think of it as a diesel that is parked for months...
  • Nov 18, 2009, 04:34 PM
    rdkenney
    Yes I have found that out ! I have an outside tank full of 50/50 fuel oil.

    Usually use the LP gas logs for heat but the women use the camp and have trouble getting it lit.
  • Mar 17, 2013, 11:55 AM
    puzzles1
    The furnace comes on and runs tills blower comes on , runs about 10 min. when blower stops, furance stops and furance will not come on again until you hit the reset bottom. This is when the house is cold.

  • All times are GMT -7. The time now is 03:18 AM.