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Tjernlund oil vent

RLuck Member Posts: 24
Went to leave a job today, oil furnace, Becket burner with a tjernlund power vent when I ended the call for heat the burner fan and the tjernlund vent continued to run, the burner circuit was no longer firing. The only way to stop it was to pull the wire from the time delay. Obviously it appears that the relay in the time delay is sticking or welded. There was no diagram and a rats nest of wires. When you kill all power, turn on, make a call for heat and then reset the primary it fires up. I'm not familiar with the order of operation on these as I never see them, and am not sure if there are multiple ways to wire it all in. So am I over thinking it? Is the time delay in the SSr1 just stuck closed locking out the burner? Thanks


  • captainco
    captainco Member Posts: 768
    That is called post-purge. It makes sure all the fumes are removed from the heat exchanger and flue. Without it you will get condensation and odors in the house and delayed afterdrip from the burner. Trial and error over the years has shown that oil needs about 8 minutes of post-purge to minimize problems.
  • RLuck
    RLuck Member Posts: 24
    So your saying that it has an 8 min post purge delay? So my lack of patience is the issue? I never see these on oil in my area so it could be that simple
  • RLuck
    RLuck Member Posts: 24
    And when I pulled the load wire off( the middle one) yes it killed the power but the time delay was still powered so I was causing the lock out? If I turned the emergency switch off and back on it would still be running. But it is possible that the venter is wired hot so the time delay off is still closed. What would the actual cause of lock out be?
  • RLuck
    RLuck Member Posts: 24
    So the lock out would be the pressure switch failure. Duh
  • Solid_Fuel_Man
    Solid_Fuel_Man Member Posts: 2,644
    I think you got it!
    Serving Northern Maine HVAC & Controls. I burn wood, it smells good!