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Lockinvar boiler KBN105

ButchG Member Posts: 1
I have a Lockinvar KBN105 boiler about 14 years old. Started getting lockout fan hi speed notices told I need a new fan assembly. I have had a tech out and checked several things like water trap. air inflow and connections bad fan is his decision. Any ideas what to look far, the problem is not consistent that's what bothers me. Is this common?


  • tim smith
    tim smith Member Posts: 2,743
    get some contact cleaner, turn power off and clean the plug terminals for the comm cable to the blower and to the board connection of same cable. Make sure all evaporated and dry before powering back up. Some times some tarnish can form on connections which will give bad signal. The board or blower connection can also have cracked or loose solder connections which will cause it also. Or just a bad blower motor. Bad wire harness possible too. Intermittent issues with blower speed can be any one of these or combination there of.
  • HomerJSmith
    HomerJSmith Member Posts: 2,406
    Removing the four wire connector the fan should run at full speed. Check that. Yes, fans need to be replaced. Check your venting to make sure that exhaust gases are not being pulled back into the boiler. Called gas reversion. Make sure the contact cleaner is electronic grade.