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Lochinvar KBN 080 fan speed high lockout

trudg01 Member Posts: 1
Hello I am a refrigeration tech but sometimes do heat calls too... My Lochinvar Knight boiler keeps locking out with the error message "Fan HIgh"... It will try to ignite 3 times and then lock out. I came home yesterday after being up North for the weekend and house was 41 degrees. Boiler will start right up on first reset but then was out this morning again. This has been happening a lot the last week. Just wondering if anyone has advice. Seems like it starts right up on first try if it has been off a while but when it trips and I try to reset right away thats when it tries 3 times and then locks out.


  • bmwpowere36m3
    bmwpowere36m3 Member Posts: 512
    Make sure there's no blockages in the intake, exhaust or condensate lines.

    I don't have the manual in front of me, but unless there's an obstruction, could be a bad blower/fan. Call Lochinvar tech, there's always super helpful.
  • HeatingQc
    HeatingQc Member Posts: 10
    I know I'm late on this one, but check the number of cycles on the unit. If there's no blockage, it's possibly that the blower is tired, and can't modulate down fast enough for the control board setpoint. It will cause a "High Fan Speed", but if you change the fan without finding what cause the issue first, you'll change it again soon or later! I normally see this on boiler with 100 000+ cycles, and we can't blame the manufacturer for as much over cycling!